(90 days)
Not Found
No
The device uses quantitative measurements of biomarkers and applies fixed cutoff values determined through statistical analysis of a training set. There is no indication of adaptive learning or complex pattern recognition characteristic of AI/ML.
No
This device is an in vitro diagnostic (IVD) test used to aid in the evaluation of patients with suspected mild traumatic brain injury by measuring biomarkers in plasma and serum. Its purpose is to assist in determining the need for a CT scan, not to treat a condition.
Yes
The text explicitly states: "The TBI test is a panel of in vitro diagnostic chemiluminescent microparticle immunoassays..." and "The interpretation of test results is used, in conjunction with other clinical information, to aid in the evaluation of patients... to assist in determining the need for a CT... scan." This indicates its purpose is to provide diagnostic information.
No
The device is an in vitro diagnostic (IVD) test that measures biomarkers in plasma and serum using chemiluminescent microparticle immunoassay (CMIA) technology on a specific hardware system (Alinity i). While it includes a software component for interpreting results, it is fundamentally a hardware-based IVD system that requires physical reagents and instrumentation.
Yes, this device is an IVD (In Vitro Diagnostic).
Here's why:
- Intended Use/Indications for Use: The very first sentence explicitly states, "The TBI test is a panel of in vitro diagnostic chemiluminescent microparticle immunoassays (CMIA)..." It also describes the test's use for quantitative measurements of biomarkers in human plasma and serum, which are biological samples taken in vitro (outside the body).
- Device Description: The description reiterates that the TBI test is a panel of "in vitro diagnostic quantitative measurements..."
- Nature of the Test: The test measures specific biomarkers (GFAP and UCH-L1) in biological fluids (plasma and serum) to provide information about a patient's condition (suspected mild traumatic brain injury). This is the core function of an in vitro diagnostic device.
- Intended User/Care Setting: The test is intended for use in "clinical laboratory settings by healthcare professionals," which is a typical environment for IVD testing.
The information provided clearly aligns with the definition and purpose of an In Vitro Diagnostic device.
N/A
Intended Use / Indications for Use
The TBI test is a panel of in vitro diagnostic chemiluminescent microparticle immunoassays (CMIA) used for the quantitative measurements of glial fibrillary acidic protein (GFAP) and ubiquitin carboxyl-terminal hydrolase L1 (UCH-L1) in human plasma and serum and provides a semi-quantitative interpretation of test results derived from these measurements using the Alinity i system.
The interpretation of test results is used, in conjunction with other clinical information, to aid in the evaluation of patients, 18 years of age or older, presenting with suspected mild traumatic brain injury (Glasgow Coma Scale score 13-15) within 12 hours of injury, to assist in determining the need for a CT (computed tomography) scan of the head. A negative test result is associated with the absence of acute intracranial lesions visualized on a head CT scan.
The TBI test is intended for use in clinical laboratory settings by healthcare professionals.
Product codes (comma separated list FDA assigned to the subject device)
QAT
Device Description
The TBI test is a panel of in vitro diagnostic quantitative measurements of GFAP and UCH-L1 and provides a semi-quantitative interpretation of GFAP and UCH-L1 in human plasma and serum.
GFAP: This assay is an automated, two-step immunoassay for the quantitative measurement of GFAP in human plasma and serum using chemiluminescent microparticle immunoassay (CMIA) technology. Sample, anti-GFAP coated paramagnetic microparticles, and assay specific diluent are combined and incubated. The GFAP present in the sample binds to the anti-GFAP coated microparticles. The mixture is washed. Anti-GFAP acridinium-labeled conjugate is added to create a reaction mixture and incubated. Following a wash cycle, Pre-Trigger and Trigger Solutions are added. The resulting chemiluminescent reaction is measured as a relative light unit (RLU). There is a direct relationship between the amount of GFAP in the sample and the RLU detected by the system optics.
UCH-L1: This assay is an automated, two-step immunoassay for the quantitative measurement of UCH-L1 in human plasma and serum using CMIA technology. Sample, anti-UCH-L1 coated paramagnetic microparticles, and assay specific diluent are combined and incubated. The UCH-L1 present in the sample binds to the anti-UCH-L1 coated microparticles. The mixture is washed. Anti-UCH-L1 acridinium-labeled conjugate is added to create a reaction mixture and incubated. Following a wash cycle, Pre-Trigger and Trigger Solutions are added. The resulting chemiluminescent reaction is measured as an RLU. There is a direct relationship between the amount of UCH-L1 in the sample and the RLU detected by the system optics.
Interpretation of Results: The assay cutoffs were established to be 35.0 pg/mL (35.0 ng/L) for GFAP and 400.0 pg/mL (400.0 ng/L) for UCH-L1. The GFAP and UCH-L1 results are reported separately, and the software provides a TBI interpretation relative to the respective cutoff values. If GFAP and UCH-L1 are both below cutoff, the interpretation is Negative. If GFAP and/or UCH-L1 are above or equal to cutoff, the interpretation is Positive. An automated TBI interpretation will not be reported for specimens without a result for GFAP and/or UCH-L1.
Mentions image processing
Not Found
Mentions AI, DNN, or ML
Not Found
Input Imaging Modality
Not Found
Anatomical Site
Not Found
Indicated Patient Age Range
18 years of age or older
Intended User / Care Setting
Clinical laboratory settings by healthcare professionals.
Description of the training set, sample size, data source, and annotation protocol
The assay cutoffs were determined by analyzing a training set with GFAP and UCH-L1 results from a total of 354 with 132 CT positive subjects with suspected mild traumatic brain injury (TBI; Glasgow Coma Scale score of 13-15). Subjects who had blood drawn within 12 hours of injury, a head CT scan determination, and were 18 years or older at the time of injury were included in the analysis.
Description of the test set, sample size, data source, and annotation protocol
Pivotal Study:
Sample Size: 1899 subjects.
Data Source: Specimens were originally collected in a prospective, multi-center clinical study that enrolled consenting men and women 18 years of age or older who presented to a health care facility (HCF) or emergency department (ED) with suspected TBI with initial Glasgow Coma Scale (GCS) scores of 9-15 and who had a CT scan performed per the clinical site's standard of care. Subjects were enrolled at 22 clinical sites in three countries: United States, Germany and Hungary. Whole blood was collected into dipotassium EDTA blood collection tubes from each subject using venipuncture and centrifuged to obtain plasma. Specimens were collected within 12 hours of head injury. The plasma specimens were divided into aliquots and frozen in cryovials before being provided to testing sites.
Annotation Protocol: CT scans were performed in accordance with the clinical site's standard of care. Images were transmitted to a central neuroimaging processing center. Images were interpreted by at least two neuroradiologists who were masked to other clinical and laboratory data; procedures for scoring images were established before conducting image review. The clinical outcome was based on the consensus interpretation between two neuroradiologists with adjudication by a third neuroradiologist if necessary. Outcomes were positive or negative as defined by the presence or absence of acute traumatic intracranial lesions, respectively. Acute intracranial lesion was defined as any trauma induced or related finding visualized upon head CT scan.
Fresh Specimen Study (Supplemental):
Sample Size: 97 subjects.
Data Source: Freshly collected plasma specimens from consenting men and women 18 years of age or older who presented to a HCF or ED with suspected mild TBI, with initial GCS scores of 13-15, and who had a CT scan of the head performed per the clinical site's standard of care. A total of 97 subjects were enrolled across 5 clinical sites in the United States. Whole blood was collected into dipotassium EDTA blood collection tubes from each subject using venipuncture and centrifuged to obtain plasma. Specimens were collected within 12 hours of head injury.
Annotation Protocol: Similar to the pivotal study, CT scans were performed in accordance with the clinical site's standard of care. Images were transmitted to a central neuroimaging processing center. Images were interpreted by at least two radiologists who were masked to other clinical and laboratory data; procedures for scoring images were established before conducting image review. The clinical outcome was based on the consensus interpretation between two radiologists, with adjudication by a third radiologist if necessary. Outcomes were positive, negative, or inconclusive as defined by the presence or absence of acute traumatic intracranial lesions, respectively. Acute intracranial lesion was defined as any trauma induced or related finding visualized upon head CT scan.
Summary of Performance Studies (study type, sample size, AUC, MRMC, standalone performance, key results)
Pivotal Clinical Performance Study
- Study Type: Clinical study using prospectively collected and archived (frozen) plasma specimens.
- Sample Size: 1899 subjects.
- Key Results:
- 120 subjects had positive CT scan results.
- 116 subjects had a positive TBI interpretation.
- 4 subjects associated with CT scan positive results had a negative TBI interpretation.
- The False Negative (FN) rate was 3.3% (4/120).
- 5 subjects in the study were identified with lesions requiring surgical intervention; none of these 5 subjects had a FN result.
- 1779 subjects with negative CT scan results, 713 had a negative TBI interpretation.
- The False Positive (FP) rate was 59.9% (1066/1779).
Fresh Specimen Study (Supplemental)
- Study Type: Clinical study using freshly collected plasma specimens.
- Sample Size: 97 subjects.
- Key Results:
- 14 subjects had positive head CT scan results.
- 14 subjects had a positive TBI test interpretation.
- The False Negatives (FN) rate was 0.0% (0 / 14).
- 83 subjects associated with negative CT scan results, 23 had a negative TBI test interpretation.
- The False Positive (FP) results rate was 72.3% (60 / 83).
System Reproducibility (GFAP)
- Study Type: Precision study per CLSI EP05-A3.
- Sample Size: 360 replicates per sample type (controls and panels).
- Key Results: Overall Reproducibility (SD, %CV) was calculated for controls and plasma panels. For example, Low Control (24.9 pg/mL) had an overall reproducibility of SD 0.97, %CV 3.9. Panel 2 (Native) (37.4 pg/mL) had an overall reproducibility of SD 1.54, %CV 4.1. Qualitative precision relative to cutoff (35.0 pg/mL) generally showed 100% correct calls for controls and panels.
System Reproducibility (UCH-L1)
- Study Type: Precision study per CLSI EP05-A3.
- Sample Size: 360 replicates per sample type (controls and panels).
- Key Results: Overall Reproducibility (SD, %CV) was calculated for controls and plasma panels. For example, Low Control (249.9 pg/mL) had an overall reproducibility of SD 9.01, %CV 3.6. Panel 2 (Native) (402.4 pg/mL) had an overall reproducibility of SD 18.93, %CV 4.7. Qualitative precision relative to cutoff (400.0 pg/mL) generally showed 100% correct calls for controls and panels.
Key Metrics (Sensitivity, Specificity, PPV, NPV, etc.)
Pivotal Clinical Performance Study (N=1899)
- Sensitivity (%): 96.7 (116 / 120); 95% CI: 91.7, 98.7
- Specificity (%): 40.1 (713 / 1779); 95% CI: 37.8, 42.4
- NPV (%): 99.4 (713 / 717); 95% CI: 98.6, 99.8
- PPV (%): 9.8 (116 / 1182); 95% CI: 8.2, 11.6
- Likelihood Ratio Negative (LR-): 0.08; 95% CI: 0.03, 0.22
- Likelihood Ratio Positive (LR+): 1.61; 95% CI: 1.53, 1.70
- Adjusted NPV (%) for 6% CT scan positive prevalence: 99.5; 95% CI: 98.6, 99.8
- Adjusted PPV (%) for 6% CT scan positive prevalence: 9.3; 95% CI: 8.9, 9.8
Fresh Specimen Study (Supplemental, N=97)
- Sensitivity (%): 100.0 (14 / 14); 95% CI: 78.5, 100.0
- Specificity (%): 27.7 (23 / 83); 95% CI: 19.2, 38.2
- NPV (%): 100.0 (23 / 23); 95% CI: 85.7, 100.0
- PPV (%): 18.9 (14 / 74); 95% CI: 11.6, 29.3
- Likelihood Ratio Negative (LR-): 0.12; 95% CI: 0.01, 1.91
- Likelihood Ratio Positive (LR+): 1.38; 95% CI: 1.21, 1.58
- Adjusted NPV for 6% prevalence rate: 99.2% (95% CI: 89.1, 99.9)
- Adjusted PPV for 6% prevalence rate: 8.1 (95% CI: 7.2, 9.1)
Predicate Device(s): If the device was cleared using the 510(k) pathway, identify the Predicate Device(s) K/DEN number used to claim substantial equivalence and list them here in a comma separated list exactly as they appear in the text. List the primary predicate first in the list.
Banyan Brain Trauma Indicator (BTI) (DEN170045)
Reference Device(s): Identify the Reference Device(s) K/DEN number and list them here in a comma separated list exactly as they appear in the text.
Not Found
Predetermined Change Control Plan (PCCP) - All Relevant Information for the subject device only (e.g. presence / absence, what scope was granted / cleared under the PCCP, any restrictions, etc).
Not Found
§ 866.5830 Brain trauma assessment test.
(a)
Identification. A brain trauma assessment test is a device that consists of reagents used to detect and measure brain injury biomarkers in human specimens. The measurements aid in the evaluation of patients with suspected mild traumatic brain injury in conjunction with other clinical information to assist in determining the need for head imaging per current standard of care.(b)
Classification. Class II (special controls). The special controls for this device are:(1) The 21 CFR 809.10(b) compliant labeling must include detailed descriptions of and results from performance testing conducted to evaluate precision, accuracy, linearity, analytical sensitivity, interference, and cross-reactivity. This information must include the following:
(i) Performance testing of device precision must, at minimum, use one unmodified clinical specimen from the intended use population with concentration of the brain injury biomarker(s) near the medical decision point. Contrived specimens that have been generated from pooling of multiple samples or spiking of purified analyte to cover the measuring range may be used, but the contrived samples must be prepared to mimic clinical specimens as closely as possible. This testing must evaluate repeatability and reproducibility using a protocol from an FDA-recognized standard.
(ii) Device performance data must be demonstrated through a clinical study and must include the following:
(A) Data demonstrating clinical validity including the clinical sensitivity and specificity, and positive and negative predictive value of the test in the intended use population of patients with suspected mild traumatic brain injury (
i.e., Glasgow Coma Score (GCS) of 13-15), or equivalent standard of care for determination of severity of traumatic brain injury (TBI).(B) Study must be performed using the operators and in settings that are representative of the types of operators and settings for which the device is intended to be used.
(C) All eligible subjects must meet the well-defined study inclusion and exclusion criteria that define the intended use population. The prevalence of diseased or injured subjects in the study population must reflect the prevalence of the device's intended use population, or alternatively, statistical measures must be used to account for any bias due to enrichment of subpopulations of the intended use population.
(D) All eligible subjects must have undergone a head computerized tomography (CT) scan or other appropriate clinical diagnostic standard used to determine the presence of an intracranial lesion as part of standard of care and must also be evaluated by the subject device. All clinical diagnostic standards used in the clinical study must follow standard clinical practice in the United States.
(E) Relevant demographic variables and baseline characteristics including medical history and neurological history. In addition, head injury characteristics, neurological assessments, and physical evidence of trauma must be provided for each subject. This information includes but is not limited to the following: Time since head injury, time from head injury to CT scan, time from head injury to blood draw, GCS score or equivalent, experience of loss of consciousness, presence of confusion, episodes of vomiting, post-traumatic amnesia characteristics, presence of post-traumatic seizures, drug or alcohol intoxication, mechanism of injury, acute intracranial lesion type, neurosurgical lesion, and cranial fracture.
(F) Each CT scan or other imaging result must be independently evaluated in a blinded manner by at least two board-certified radiologists to determine whether it is positive or negative as defined by the presence or absence of acute intracranial lesions. This independent review must be conducted without access to test results of the device. Prior to conducting the review, the criteria and procedures to be followed for scoring the images must be established, including the mechanism for determining consensus.
(G) All the clinical samples must be tested with the subject device blinded to the TBI status and the neurological-lesion-status of the subject.
(H) Details on how missing values in data are handled must be provided.
(I) For banked clinical samples, details on storage conditions and storage period must be provided. In addition, a specimen stability study must be conducted for the duration of storage to demonstrate integrity of archived clinical samples. The samples evaluated in the assay test development must not be used to establish the clinical validity of the assays.
(iii) Performance testing of device analytical specificity must include the most commonly reported concomitant medications present in specimens from the intended use population. Additionally, potential cross-reacting endogenous analytes must be evaluated at the highest concentration reported in specimens from the intended use population.
(iv) Expected/reference values generated by testing a statistically appropriate number of samples from apparently healthy normal individuals.
(2) The 21 CFR 809.10(a) and (b) compliant labeling must include the following limitations:
(i) A limiting statement that this device is not intended to be used a stand-alone device but as an adjunct to other clinical information to aid in the evaluation of patients who are being considered for standard of care neuroimaging.
(ii) A limiting statement that reads “A negative result is generally associated with the absence of acute intracranial lesions. An appropriate neuroimaging method is required for diagnosis of acute intracranial lesions.”
(iii) As applicable, a limiting statement that reads “This device is for use by laboratory professionals in a clinical laboratory setting.”
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Image /page/0/Picture/0 description: The image contains the logo of the U.S. Food and Drug Administration (FDA). The logo consists of two parts: the Department of Health & Human Services logo on the left and the FDA logo on the right. The FDA logo is in blue and includes the letters "FDA" followed by the words "U.S. FOOD & DRUG ADMINISTRATION" stacked on top of each other.
March 2, 2023
Abbott Laboratories Lisa Kelly Regulatory Affairs Associate Director 100 Abbott Park Road Abbott Park, Illinois 60064
Re: K223602
Trade/Device Name: TBI Regulation Number: 21 CFR 866.5830 Regulation Name: Brain trauma assessment test Regulatory Class: Class II Product Code: QAT Dated: November 30, 2022 Received: December 2, 2022
Dear Lisa Kelly:
We have reviewed your Section 510(k) premarket notification of intent to market the device referenced above and have determined the device is substantially equivalent (for the indications for use stated in the enclosure) to legally marketed predicate devices marketed in interstate commerce prior to May 28, 1976, the enactment date of the Medical Device Amendments, or to devices that have been reclassified in accordance with the provisions of the Federal Food, Drug, and Cosmetic Act (Act) that do not require approval of a premarket approval application (PMA). You may, therefore, market the device, subject to the general controls provisions of the Act. Although this letter refers to your product as a device, please be aware that some cleared products may instead be combination products. The 510(k) Premarket Notification Database located at https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfpmn/pmn.cfm identifies combination product submissions. The general controls provisions of the Act include requirements for annual registration, listing of devices, good manufacturing practice, labeling, and prohibitions against misbranding and adulteration. Please note: CDRH does not evaluate information related to contract liability warranties. We remind you, however, that device labeling must be truthful and not misleading.
If your device is classified (see above) into either class II (Special Controls) or class III (PMA), it may be subject to additional controls. Existing major regulations affecting your device can be found in the Code of Federal Regulations, Title 21, Parts 800 to 898. In addition, FDA may publish further announcements concerning your device in the Federal Register.
Please be advised that FDA's issuance of a substantial equivalence determination does not mean that FDA has made a determination that your device complies with other requirements of the Act or any Federal statutes and regulations administered by other Federal agencies. You must comply with all the Act's
1
requirements, including, but not limited to: registration and listing (21 CFR Part 807); labeling (21 CFR Part 801 and Part 809); medical device reporting of medical device-related adverse events) (21 CFR 803) for devices or postmarketing safety reporting (21 CFR 4, Subpart B) for combination products (see https://www.fda.gov/combination-products/guidance-regulatory-information/postmarketing-safety-reportingcombination-products); good manufacturing practice requirements as set forth in the quality systems (OS) regulation (21 CFR Part 820) for devices or current good manufacturing practices (21 CFR 4, Subpart A) for combination products; and, if applicable, the electronic product radiation control provisions (Sections 531-542 of the Act); 21 CFR 1000-1050.
Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21 CFR Part 807.97). For questions regarding the reporting of adverse events under the MDR regulation (21 CFR Part 803), please go to https://www.fda.gov/medical-device-safety/medical-device-reportingmdr-how-report-medical-device-problems.
For comprehensive regulatory information about mediation-emitting products, including information about labeling regulations, please see Device Advice (https://www.fda.gov/medicaldevices/device-advice-comprehensive-regulatory-assistance) and CDRH Learn (https://www.fda.gov/training-and-continuing-education/cdrh-learn). Additionally, you may contact the Division of Industry and Consumer Education (DICE) to ask a question about a specific regulatory topic. See the DICE website (https://www.fda.gov/medical-device-advice-comprehensive-regulatoryassistance/contact-us-division-industry-and-consumer-education-dice) for more information or contact DICE by email (DICE@fda.hhs.gov) or phone (1-800-638-2041 or 301-796-7100).
Sincerely,
Ying Mao -S
Ying Mao, Ph.D. Branch Chief Division of Immunology and Hematology Devices OHT7: Office of In Vitro Diagnostics Office of Product Evaluation and Quality Center for Devices and Radiological Health
Enclosure
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Indications for Use
510(k) Number (if known) K223602
Device Name TBI
Indications for Use (Describe)
The TBI test is a panel of in vitro diagnostic chemiluminescent microparticle immunoassays (CMIA) used for the quantitative measurements of glial fibrillary acidic protein (GFAP) and ubiquitin carboxyl-terminal hydrolase L1 (UCH-L1) in human plasma and serum and provides a semi-quantitative interpretation of test results derived from these measurements using the Alinity i system.
The interpretation of test results is used, in cominction, to aid in the evaluation of patients, 18 years of age or older, presenting with suspected mild traumatic brain injury (Glasgow Coma Scale score 13-15) within 12 hours of injury, to assist in determining the need for a CT (computed tomography) scan of the head. A negative test result is associated with the absence of acute intracranial lesions visualized on a head CT scan.
The TBI test is intended for use in clinical laboratory settings by healthcare professionals.
| Type of Use (Select one or both, as applicable) | |
|---|---|
| ☑ Prescription Use (Part 21 CFR 801 Subpart D) | ☐ Over-The-Counter Use (21 CFR 801 Subpart C) |
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510(k) Summary (Summary of Safety and Effectiveness)
This summary of the 510(k) safety and effectiveness information is being submitted in accordance with the requirements of SMDA 1990 and 21 CFR § 807.92.
I. Applicant Name
Abbott Diagnostics Department 09AA, Building CP01 100 Abbott Park Road Abbott Park, IL 60064
Primary contact person for all communications:
Lisa Kelly, Associate Director of Regulatory Affairs Abbott Core Diagnostics lisa.lukowski@abbott.com Phone (224) 668-8849 Fax (224) 280-2358
Secondary contact person for all communications:
Noah Lermer PhD, Director of Regulatory Affairs Abbott Core Diagnostics noah.lermer@abbott.com Phone (224) 668-7613 Fax (224) 667-1221
Date Summary Prepared: November 30, 2022
II. Device Name
TBI
Reagents
Trade Name: Glial fibrillary acidic protein (GFAP) Ubiquitin carboxyl-terminal hydrolase L1 (UCH-L1) Device Classification: Class II (Special controls) Classification Name: Brain trauma assessment test Governing Regulation: 21 CFR § 866.5830 Product Code: QAT
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III. Predicate Device
Banyan Brain Trauma Indicator (BTI) (DEN170045)
IV. Description of Device
A. Reagents
The kit configurations of the GFAP and UCH-L1 reagent kits are described below.
| List Number | ||
|---|---|---|
| GFAP 04W1722 | UCH-L1 04W1922 | |
| Tests per cartridge | 100 | 100 |
| Number of cartridges per kit | 2 | 2 |
| Tests per kit | 200 | 200 |
| Microparticles | 7.1 mL | 7.1 mL |
| Conjugate | 6.4 mL | 12.5 mL |
| Assay Specific Diluent | 6.4 mL | 10.5 mL |
GFAP Reagent Kit
| Microparticles: | Anti-GFAP (rabbit, monoclonal) coated microparticles in
TRIS buffer with protein (bovine) stabilizer. Minimum
concentration: 0.05% solids. Preservative: ProClin 300. |
|----------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| Conjugate: | Anti-GFAP (mouse, monoclonal) acridinium-labeled
conjugate in MES buffer with protein (bovine) stabilizer.
Minimum concentration: 0.2 mg/L. Preservative:
ProClin 300. |
| Assay Specific
Diluent: | TRIS buffer with protein (bovine) stabilizer. Preservative:
ProClin 300. |
UCH-L1 Reagent Kit
| Microparticles: | Anti-UCH-L1 (mouse, monoclonal) coated microparticles
in TRIS buffer with protein (bovine) stabilizer. Minimum
concentration: 0.05% solids. Preservative: sodium azide. |
|----------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| Conjugate: | Anti-UCH-L1 (mouse, monoclonal) acridinium-labeled
conjugate in MES buffer with protein (bovine) stabilizer.
Minimum concentration: 0.2 mg/L. Preservative:
ProClin 300. |
| Assay Specific
Diluent: | TRIS buffer with protein (bovine) stabilizer. Preservative:
sodium azide. |
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B. Biological Principles of the Procedure
The TBI test is a panel of in vitro diagnostic quantitative measurements of GFAP and UCH-L1 and provides a semi-quantitative interpretation of GFAP and UCH-L1 in human plasma and serum.
GFAP
This assay is an automated, two-step immunoassay for the quantitative measurement of GFAP in human plasma and serum using chemiluminescent microparticle immunoassay (CMIA) technology.
Sample, anti-GFAP coated paramagnetic microparticles, and assay specific diluent are combined and incubated. The GFAP present in the sample binds to the anti-GFAP coated microparticles. The mixture is washed. Anti-GFAP acridinium-labeled conjugate is added to create a reaction mixture and incubated. Following a wash cycle, Pre-Trigger and Trigger Solutions are added.
The resulting chemiluminescent reaction is measured as a relative light unit (RLU). There is a direct relationship between the amount of GFAP in the sample and the RLU detected by the system optics.
UCH-L1
This assay is an automated, two-step immunoassay for the quantitative measurement of UCH-L1 in human plasma and serum using CMIA technology.
Sample, anti-UCH-L1 coated paramagnetic microparticles, and assay specific diluent are combined and incubated. The UCH-L1 present in the sample binds to the anti-UCH-L1 coated microparticles. The mixture is washed. Anti-UCH-L1 acridinium-labeled conjugate is added to create a reaction mixture and incubated. Following a wash cycle, Pre-Trigger and Trigger Solutions are added.
The resulting chemiluminescent reaction is measured as an RLU. There is a direct relationship between the amount of UCH-L1 in the sample and the RLU detected by the system optics.
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C. Interpretation of Results
The assay cutoffs were established to be 35.0 pg/mL (35.0 ng/L) for GFAP and 400.0 pg/mL (400.0 ng/L) for UCH-L1.
The GFAP and UCH-L1 results are reported separately and the software provides a TBI interpretation relative to the respective cutoff values as shown in the following table.
| Specification for Constituent Assay Results | TBI Result | TBI Interpretation |
|---|---|---|
| GFAP and UCH-L1 below (" or "" should be considered above the cutoff and a result flagged "in vitro | ||
| diagnostic chemiluminescent | ||
| microparticle immunoassays | ||
| (CMIA) used for the quantitative | ||
| measurements of glial fibrillary | ||
| acidic protein (GFAP) and ubiquitin | ||
| carboxyl-terminal hydrolase L1 | ||
| (UCH-L1) in human plasma and | ||
| serum and provides a semi- | ||
| quantitative interpretation of test | ||
| results derived from these | ||
| measurements using the Alinity i | ||
| system. | ||
| The interpretation of test results is | ||
| used, in conjunction with other | ||
| clinical information, to aid in the | ||
| evaluation of patients, 18 years of | ||
| age or older, presenting with | ||
| suspected mild traumatic brain | ||
| injury (Glasgow Coma Scale score | ||
| 13-15) within 12 hours of injury, to | ||
| assist in determining the need for a | ||
| CT (computed tomography) scan of | ||
| the head. A negative test result is | ||
| associated with the absence of acute | ||
| intracranial lesions visualized on a | ||
| head CT scan. | ||
| The TBI test is intended for use in | ||
| clinical laboratory settings by | ||
| healthcare professionals. | The Banyan BTI is an in vitro | |
| diagnostic chemiluminescent enzyme- | ||
| linked immunosorbent assay (ELISA). | ||
| The assay provides a semi-quantitative | ||
| measurement of the concentrations of | ||
| ubiquitin C-terminal hydrolase-L1 | ||
| (UCH-L1) and glial fibrillary acidic | ||
| protein (GFAP) in human serum and | ||
| is used with the Synergy 2 | ||
| Multi-mode Reader. | ||
| The assay results obtained from serum | ||
| collected within 12 hours of suspected | ||
| head injury are used, along with other | ||
| available clinical information, to aid in | ||
| the evaluation of patients 18 years of | ||
| age and older with suspected traumatic | ||
| brain injury (Glasgow Coma Scale | ||
| score 13-15). A negative assay result | ||
| is associated with the absence of acute | ||
| intracranial lesions visualized on a | ||
| head CT (computed tomography) | ||
| scan. | ||
| Intended Use | ||
| Setting | Clinical Laboratory | Same |
| Measurands | GFAP and UCH-L1 | Same |
| Assay | ||
| Technology | Chemiluminescent microparticle | |
| immunoassays (CMIA) | Enzyme-linked immunosorbent assay | |
| Similarities and Differences Between Subject & Predicate Device | ||
| Subject Device: | ||
| TBI | Predicate Device: | |
| Banyan BTI (DEN170045) | ||
| Reportable Result | Quantitative results for GFAP and | |
| UCH--L1 and semi-quantitative | ||
| interpretation for TBI | Same | |
| Assay Format | Two separate test kits – one for | |
| GFAP and one for UCH-L1 | Two test kits on separate 96-well | |
| microtiter plates – one for GFAP and | ||
| one for UCH-L1 | ||
| Detection | ||
| Technology | Chemiluminescence | Same |
| General Device Characteristic Differences | ||
| Platform | Alinity i | Synergy 2 Multi-mode Reader |
| (BioTek Instruments, Inc.) | ||
| Specimen Type | Serum and Plasma | Serum |
| Sample Volume | GFAP kit: 200 µL | |
| UCH-L1 kit: 150 µL | GFAP kit: 150 µL | |
| UCH-L1 kit: 100 µL | ||
| Time to Result | Approximately 18 minutes | Approximately 4 hours |
| Reportable | ||
| Interval | Analytical Measuring Interval: | |
| GFAP: 6.1 - 42,000.0 pg/mL | ||
| UCH-L1: 26.3 – 25,000.0 pg/mL |
Reportable Interval:
GFAP: 3.2 - 42,000.0 pg/mL
UCH-L1: 18.3 - 25,000.0 pg/mL | GFAP: 10 - 320 pg/mL
UCH-L1: 80 - 2560 pg/mL |
| GFAP Cutoff | 35.0 pg/mL | 22 pg/mL |
| UCH-L1 Cutoff | 400.0 pg/mL | 327 pg/mL |
Comparison of Subject Device (TBI for Alinity i) to Predicate Device (Banyan BTI)
9
10
VII. Summary of Nonclinical Performance
A. Reportable Interval
Based on representative data, the ranges over which results can be reported are provided below according to the definitions from CLSI EP34, 1st ed.
| | GFAP
(pg/mL, ng/L) | UCH-L1
(pg/mL, ng/L) |
|--------------------------------------|-----------------------|-------------------------|
| Analytical Measuring Interval (AMI)a | 6.1 - 42,000.0 | 26.3 - 25,000.0 |
| Reportable Intervalb | 3.2 - 42,000.0 | 18.3 - 25,000.0 |
a AMI: The AMI extends from the limit of quantitation (LoQ) to the upper limit of quantitation (ULoQ). This is determined by the range of values in pg/mL (ng/L) that demonstrated acceptable performance for linearity, imprecision, and bias.
b The reportable interval extends from the limit of detection (LoD) to the upper limit of the AMI.
NOTE: The default Low Linearity value of the assay file corresponds to the lower limit of the reportable interval.
B. Within-Laboratory Precision
GFAP
A study was performed based on guidance from CLSI EP05-A3. T Testing was conducted using 2 lots of the GFAP reagents, 2 lots of the GFAP Calibrators, 1 lot of the GFAP Controls, and 2 instruments. Three controls and eight human plasma panels (one native panel and seven panels supplemented with GFAP analyte) were tested in a minimum of 2 replicates at 2 separate times per day on 20 days on 4 reagent lot/calibrator lot/instrument combinations, where a unique reagent lot and a unique calibrator lot are paired with both instruments. The performance is shown in the following table.
^ Clinical and Laboratory Standards Institute (CLSI). Establishing and Verifying an Extended Measuring Interval Through Specimen Dilution and Spiking. 1st ed. CLSI Guideline EP34. Wayne, PA: CLSI; 2018.
- Clinical and Laboratory Standards Institute (CLSI). Evaluation of Quantitative Measurement Procedures: Approved Guideline-Third Edition. CLSI Document EP05-A3. Wayne, PA: CLSI; 2014.
11
| | | Mean | Within-Run | | Between-Run | | Between-Day | | Between-Lot | | Between-
Instrument | | Overall
Within-
Laboratoryª | |
|------------------|-----|------------------|------------|-----|-------------|-----|-------------|-----|-------------|-----|------------------------|-----|-----------------------------------|-----|
| Sample | N | (pg/mL,
ng/L) | SD | %CV | SD | %CV | SD | %CV | SD | %CV | SD | %CV | SD | %CV |
| Low Control | 479 | 25.4 | 0.76 | 3.0 | 0.70 | 2.7 | 0.12 | 0.5 | 0.43 | 1.7 | 0.53 | 2.1 | 1.24 | 4.9 |
| Medium Control | 480 | 504.8 | 12.89 | 2.6 | 11.67 | 2.3 | 0.00 | 0.0 | 1.40 | 0.3 | 6.38 | 1.3 | 18.58 | 3.7 |
| High Control | 479 | 31608.5 | 758.80 | 2.4 | 846.98 | 2.7 | 288.19 | 0.9 | 968.97 | 3.1 | 423.35 | 1.3 | 1579.35 | 5.0 |
| Panel 1 | 479 | 20.4 | 0.69 | 3.4 | 0.64 | 3.1 | 0.36 | 1.8 | 0.02 | 0.1 | 0.19 | 0.9 | 1.03 | 5.0 |
| Panel 2 (Native) | 474 | 37.7 | 1.11 | 2.9 | 0.80 | 2.1 | 0.37 | 1.0 | 0.15 | 0.4 | 0.20 | 0.5 | 1.43 | 3.8 |
| Panel 3 | 479 | 40.2 | 1.20 | 3.0 | 1.03 | 2.6 | 0.42 | 1.0 | 0.19 | 0.5 | 0.00 | 0.0 | 1.65 | 4.1 |
| Panel 4 | 480 | 95.6 | 2.41 | 2.5 | 2.34 | 2.4 | 0.00 | 0.0 | 0.36 | 0.4 | 1.29 | 1.3 | 3.62 | 3.8 |
| Panel 5 | 480 | 3097.2 | 72.89 | 2.4 | 63.34 | 2.0 | 55.85 | 1.8 | 55.24 | 1.8 | 36.55 | 1.2 | 129.74 | 4.2 |
| Panel 6 | 478 | 7586.3 | 168.16 | 2.2 | 187.23 | 2.5 | 84.73 | 1.1 | 177.85 | 2.3 | 48.77 | 0.6 | 323.30 | 4.3 |
| Panel 7 | 480 | 15462.7 | 346.62 | 2.2 | 389.78 | 2.5 | 289.53 | 1.9 | 441.47 | 2.9 | 92.99 | 0.6 | 747.96 | 4.8 |
| Panel 8 | 478 | 36874.7 | 969.22 | 2.6 | 1233.45 | 3.3 | 0.00 | 0.0 | 1435.60 | 3.9 | 509.41 | 1.4 | 2186.60 | 5.9 |
ª Overall within-laboratory variability contains within-run, between-lot, and between-instrument variance components.
12
Qualitative Precision: Results Relative to Cutoff
The qualitative analysis of precision results relative to the cutoff (35.0 pg/mL) was performed using the precision data generated for all instruments and reagent lots.
The GFAP mean (pg/mL), number of results greater than or equal to the cutoff, and % correct call for each GFAP panel and GFAP control levels for all instruments and reagent lots are presented in the table below.
| Sample | N | Mean
(pg/mL) | # of Results
≥ 35.0 (pg/mL) / N | % of Correct
Calla |
|-------------------|-----|-----------------|------------------------------------|-----------------------|
| Low Controlb | 479 | 25.4 | 0 / 479 | 100.0 |
| Medium Controld | 480 | 504.8 | 480 / 480 | 100.0 |
| High Controld | 479 | 31,608.5 | 479 / 479 | 100.0 |
| Panel 1b | 479 | 20.4 | 0 / 479 | 100.0 |
| Panel 2 (Native)c | 474 | 37.7 | 462 / 474 | 100.0 |
| Panel 3 c | 479 | 40.2 | 479 / 479 | 100.0 |
| Panel 4d | 480 | 95.6 | 480 / 480 | 100.0 |
| Panel 5d | 480 | 3097.2 | 480 / 480 | 100.0 |
| Panel 6d | 478 | 7586.3 | 478 / 478 | 100.0 |
| Panel 7d | 480 | 15,462.7 | 480 / 480 | 100.0 |
| Panel 8d | 478 | 36,874.7 | 478 / 478 | 100.0 |
a Replicates for positive samples should always be > cutoff, replicates for negative samples should always be * Clinical and Laboratory Standards Institute (CLSI). Evaluation of Quantitative Measurement Procedures: Approved Guideline-Third Edition. CLSI Document EP05-A3. Wayne, PA: CLSI; 2014.
13
lot/calibrator lot/instrument combinations, where a unique reagent lot and a unique calibrator lot are paired with both instruments. The performance is shown in the following table.
14
| | | Mean | Within-Run | | Between-Run | | Between-Day | | Between-Lot | | Between-Instrument | | Overall
Within-
Laboratorya | |
|------------------|-----|------------------|------------|-----|-------------|-----|-------------|-----|-------------|-----|--------------------|-----|-----------------------------------|-----|
| Sample | N | (pg/mL,
ng/L) | SD | %CV | SD | %CV | SD | %CV | SD | %CV | SD | %CV | SD | %CV |
| Low Control | 479 | 247.5 | 9.16 | 3.7 | 4.99 | 2.0 | 3.13 | 1.3 | 1.62 | 0.7 | 1.07 | 0.4 | 11.06 | 4.5 |
| Medium Control | 479 | 2019.6 | 47.72 | 2.4 | 28.81 | 1.4 | 19.81 | 1.0 | 17.23 | 0.9 | 0.00 | 0.0 | 61.62 | 3.1 |
| High Control | 477 | 15179.4 | 367.43 | 2.4 | 219.00 | 1.4 | 120.20 | 0.8 | 0.00 | 0.0 | 59.99 | 0.4 | 448.35 | 3.0 |
| Panel 1 | 480 | 177.6 | 7.20 | 4.1 | 5.15 | 2.9 | 1.68 | 0.9 | 0.00 | 0.0 | 5.59 | 3.1 | 10.60 | 6.0 |
| Panel 2 (Native) | 471 | 391.8 | 15.53 | 4.0 | 4.50 | 1.1 | 7.18 | 1.8 | 1.27 | 0.3 | 14.89 | 3.8 | 23.15 | 5.9 |
| Panel 3 | 479 | 419.8 | 14.47 | 3.4 | 8.81 | 2.1 | 6.95 | 1.7 | 0.00 | 0.0 | 14.86 | 3.5 | 23.58 | 5.6 |
| Panel 4 | 477 | 823.8 | 27.42 | 3.3 | 21.32 | 2.6 | 8.46 | 1.0 | 0.00 | 0.0 | 25.33 | 3.1 | 43.81 | 5.3 |
| Panel 5 | 476 | 1553.8 | 53.15 | 3.4 | 28.09 | 1.8 | 25.67 | 1.7 | 9.83 | 0.6 | 21.27 | 1.4 | 69.44 | 4.5 |
| Panel 6 | 479 | 4793.5 | 164.54 | 3.4 | 138.24 | 2.9 | 0.00 | 0.0 | 0.00 | 0.0 | 115.93 | 2.4 | 244.18 | 5.1 |
| Panel 7 | 480 | 7974.6 | 269.27 | 3.4 | 161.73 | 2.0 | 72.92 | 0.9 | 21.25 | 0.3 | 145.84 | 1.8 | 354.54 | 4.4 |
| Panel 8 | 472 | 19165.5 | 619.10 | 3.2 | 428.85 | 2.2 | 162.96 | 0.9 | 0.00 | 0.0 | 290.87 | 1.5 | 823.62 | 4.3 |
ª Overall within-laboratory variability contains within-run, between-lot, and between-instrument variance components.
15
Qualitative Precision: Results Relative to Cutoff
The qualitative analysis of precision results relative to the cutoff (400.0 pg/mL) was performed using the precision data generated for all instruments and reagent lots.
The UCH-L1 mean (pg/mL), number of results greater than or equal to the cutoff, and % correct call for each UCH-L1 panel and UCH-L1 control levels for all instruments and reagent lots are presented in the table below.
| Sample | N | Mean
(pg/mL) | # of Results
≥ 400.0 (pg/mL) / N | % of Correct
Calla |
|-------------------|-----|-----------------|-------------------------------------|-----------------------|
| Low Controlb | 479 | 247.5 | 0 / 479 | 100.0 |
| Medium Controld | 479 | 2019.6 | 479 / 479 | 100.0 |
| High Controld | 477 | 15,179.4 | 477 / 477 | 100.0 |
| Panel 1b | 480 | 177.6 | 0 / 480 | 100.0 |
| Panel 2 (Native)c | 471 | 391.8 | 164 / 471 | 100.0 |
| Panel 3c | 479 | 419.8 | 391 / 479 | 100.0 |
| Panel 4d | 477 | 823.8 | 477 / 477 | 100.0 |
| Panel 5d | 476 | 1553.8 | 476 / 476 | 100.0 |
| Panel 6d | 479 | 4793.5 | 479 / 479 | 100.0 |
| Panel 7d | 480 | 7974.6 | 480 / 480 | 100.0 |
| Panel 8d | 472 | 19,165.5 | 472 / 472 | 100.0 |
a Replicates for positive samples should always be ≥ cutoff, replicates for negative samples should always be 60 replicates of zero-analyte samples. The observed GFAP LoB was 1.6 pg/mL (1.6 ng/L). The observed UCH-L1 LoB was 6.1 pg/mL (6.1 ng/L).
- . The LoD represents the lowest concentration at which the analyte can be detected with 95% probability based on n ≥ 60 replicates of low-analyte level samples. The observed GFAP LoD was 2.2 pg/mL (2.2 ng/L). The observed UCH-L1 LoD was 16.1 pg/mL (16.1 ng/L).
- . The LoQ is defined as the lowest concentration at which a maximum allowable precision of 20.0 %CV was met and was determined from n ≥ 60 replicates of low-analyte level samples. The observed GFAP LoQ was 2.4 pg/mL (2.4 ng/L). The observed UCH-L1 LoQ was 16.1 pg/mL (16.1 ng/L).
D. Linearity
GFAP
A study was performed based on guidance from CLSI EP06, 2nd ed.1
This assay is linear across the analytical measuring interval of 6.1 to 42,000.0 pg/mL
(6.1 to 42,000.0 ng/L).
UCH-LI
A study was performed based on guidance from CLSI EP06, 2nd ed.+
This assay is linear across the analytical measuring interval of 26.3 to 25.000.0 pg/mL
(26.3 to 25,000.0 ng/L).
Clinical and Laboratory Standards Institute (CLSI). Evaluation of Detection Capability for Clinical Laboratory Measurement Procedures; Approved Guideline-Second Edition. CLSI Document EP17-A2. Wayne, PA: CLSI; 2012.
് Clinical and Laboratory Standards Institute (CLSI). Evaluation of the Linearity of Quantitative Measurement Procedures. 2nd ed. CLSI Guideline EP06. Wayne, PA: CLSI: 2020.
- Clinical and Laboratory Standards Institute (CLSI). Evaluation of the Linearity of Quantitative Measurement Procedures. 2nd ed. CLSI Guideline EP06. Wayne, PA: CLSI; 2020.
17
E. Analytical Specificity
Interference
Potentially Interfering Endogenous Substances
A study was performed based on guidance from CLSI EP07, 3rd ed.* Each substance was tested at 2 levels of the GFAP analyte (approximately 25 pg/mL and 10,000 pg/mL) and at 2 levels of the UCH-L1 analyte (approximately 280 pg/mL and 5000 pg/mL).
No significant interference (interference within ± 10.0%) was observed at the following concentrations.
| No Significant Interference (Interference within ± 10.0%) | ||
|---|---|---|
| Interferent Level | ||
| Potentially Interfering Substance | GFAP | UCH-L1 |
| Conjugated Bilirubin | 40 mg/dL | 40 mg/dL |
| Unconjugated Bilirubin | 40 mg/dL | 20 mg/dL |
| Hemoglobin | 1000 mg/dL | 1000 mg/dL |
| Intralipid | 1500 mg/dL | 2000 mg/dL |
| Total Protein | 10 g/dL | 9 g/dL |
| Glucose | 1000 mg/dL | 1000 mg/dL |
| Heterophilic Antibodies (HAMA) | 80x activity | 80x activity |
| Rheumatoid Factor (RF) | 500 IU/mL | 500 IU/mL |
- Clinical and Laboratory Standards Institute (CLSI). Interference Testing in Clinical Chemistry. 3rd ed. CLSI Guideline EP07. Wayne, PA: CLSI; 2018.
18
Interference beyond ± 10.0% (based on 95% Confidence Interval [CI]) was
observed at the concentrations shown below for the following substances.
| Interference beyond ± 10.0% (based on 95% CI) | ||||
|---|---|---|---|---|
| Assay | Potentially Interfering | |||
| Substance | Interferent | |||
| Level | Analyte | |||
| Level | % Interference | |||
| (95% CI) | ||||
| GFAP | Intralipid | 2000 mg/dL | 10,000 pg/mL | -10.3% |
| (-11.3%, -9.3%) | ||||
| GFAP | Total Protein | 15 g/dL | 10,000 pg/mL | -15.6% |
| (-16.7%, -14.6%) | ||||
| UCH-L1 | Unconjugated Bilirubin | 40 mg/dL | 280 pg/mL | 9.2% |
| (7.7%, 10.7%) | ||||
| UCH-L1 | Total Protein | 15 g/dL | 280 pg/mL | -19.0% |
| (-21.5%, -16.5%) | ||||
| UCH-L1 | Total Protein | 15 g/dL | 5000 pg/mL | -16.9% |
| (-18.5%, -15.4%) |
19
Potentially Interfering Drugs
A study was performed based on guidance from CLSI EP07, 3rd ed. * Each substance was tested at 2 levels of the GFAP analyte (approximately 25 pg/mL and 10,000 pg/mL) and at 2 levels of the UCH-L1 analyte (approximately 280 pg/mL and 5000 pg/mL).
No significant interference (interference within ± 10.0%) was observed at the
following concentrations.
| No Significant Interference (Interference within ± 10.0%) | ||
|---|---|---|
| Potentially Interfering Substance | Interferent Level | |
| GFAP | UCH-L1 | |
| Acetaminophen | 20 mg/dL | 20 mg/dL |
| Acetylcysteine | 15 mg/dL | 9 mg/dL |
| Acetylsalicylic Acid | 65 mg/dL | 65 mg/dL |
| Amphetamine | 33 µg/dL | 33 µg/dL |
| Ampicillin-Na | 7.5 mg/dL | 7.5 mg/dL |
| Ascorbic Acid | 5.25 mg/dL | 5.25 mg/dL |
| Benzoylecgonine | 200 µg/dL | 200 µg/dL |
| Biotin | 4250 ng/mL | 4250 ng/mL |
| Brivaracetam | 1.05 mg/dL | 1.05 mg/dL |
| Calcium dobesilate | 6 mg/dL | 2 mg/dL |
| Cannabinoids | 50 ng/mL | 50 ng/mL |
| Carbamazepine | 4.5 mg/dL | 4.5 mg/dL |
| Cefoxitin | 660 mg/dL | 660 mg/dL |
| Celecoxib | 879 µg/dL | 879 µg/dL |
| Clopidogrel (Plavix) | 9 µg/mL | 9 µg/mL |
| Codeine | 141 µg/dL | 141 µg/dL |
| Cyclobenzaprine | 10.2 µg/dL | 10.2 µg/dL |
| Cyclosporine | 0.18 mg/dL | 0.18 mg/dL |
| No Significant Interference (Interference within ± 10.0%) | ||
| Potentially Interfering Substance | Interferent Level | |
| GFAP | UCH-L1 | |
| Diazepam | 3 mg/dL | 3 mg/dL |
| Doxycycline | 1.8 mg/dL | 1.8 mg/dL |
| EDDP | 318 µg/dL | 318 µg/dL |
| Ethanol | 3000 mg/dL | 1000 mg/dL |
| Fentanyl | 0.03 mg/dL | 0.03 mg/dL |
| Heparin | 330 U/dL | 330 U/dL |
| Ibuprofen | 50 mg/dL | 50 mg/dL |
| Imipramine | 0.0315 mg/dL | 0.0315 mg/dL |
| Levodopa | 0.75 mg/dL | 0.75 mg/dL |
| Methadone | 318 µg/dL | 318 µg/dL |
| d-Methamphetamine | 400 µg/dL | 400 µg/dL |
| Methaqualone | 200 µg/dL | 200 µg/dL |
| Methyldopa | 2.25 mg/dL | 2.25 mg/dL |
| Methylenedioxy methamphetamine (MDMA) | 500 ng/mL | 500 ng/mL |
| Metoprolol | 0.5 mg/dL | 0.5 mg/dL |
| Metronidazole | 12.3 mg/dL | 12.3 mg/dL |
| Morphine | 780 µg/dL | 780 µg/dL |
| Naproxen | 36 mg/dL | 36 mg/dL |
| Nicardipine | 46.5 µg/dL | 46.5 µg/dL |
| Ondansetron | 34.2 µg/dL | 34.2 µg/dL |
| Oxazepam | 425 µg/dL | 432 µg/dL |
| Phencyclidine | 20 µg/dL | 20 µg/dL |
| Propoxyphene | 321 µg/dL | 321 µg/dL |
| Rifampicin | 4.8 mg/dL | 4.8 mg/dL |
| Secobarbital | 1.59 mg/dL | 1.59 mg/dL |
| Theophylline | 6 mg/dL | 6 mg/dL |
| Warfarin (Coumadin) | 7.5 mg/dL | 7.5 mg/dL |
- Clinical and Laboratory Standards Institute (CLSI). Interference Testing in Clinical Chemistry. 3rd ed. CLSI Guideline EP07. Wayne, PA: CLSI; 2018.
20
21
Interference beyond ± 10.0% (based on 95% CI) was observed at the concentrations shown below for the following substances.
| Interference beyond ± 10.0% (based on 95% CI) | ||||
|---|---|---|---|---|
| Assay | Potentially Interfering | |||
| Substance | Interferent | |||
| Level | Analyte | |||
| Level | % Interference | |||
| (95% CI) | ||||
| GFAP | Ethanol | 5000 mg/dL | 25 pg/mL | -9.3% |
| (-10.2%, -8.4%) | ||||
| GFAP | Ethanol | 5000 mg/dL | 10,000 pg/mL | -13.0% |
| (-13.9%, -12.2%) | ||||
| UCH-L1 | Acetylcysteine | 13 mg/dL | 280 pg/mL | 10.7% |
| (9.4%, 12.1%) | ||||
| UCH-L1 | Acetylcysteine | 15 mg/dL | 5000 pg/mL | 8.4% |
| (6.1%, 10.8%) | ||||
| UCH-L1 | Calcium dobesilate | 6 mg/dL | 280 pg/mL | 13.0% |
| (11.8%, 14.2%) | ||||
| UCH-L1 | Calcium dobesilate | 6 mg/dL | 5000 pg/mL | 11.9% |
| (10.2%, 13.5%) | ||||
| UCH-L1 | Ethanol | 5000 mg/dL | 280 pg/mL | 14.9% |
| (12.9%, 17.0%) | ||||
| UCH-L1 | Ethanol | 5000 mg/dL | 5000 pg/mL | 10.9% |
| (8.6%, 13.2%) |
Cross-Reactants
GFAP
A study was performed based on guidance from CLSI EP07, 3rd ed. * Samples containing the cross-reactants listed below were prepared in GFAP depleted plasma and tested with the GFAP assay on the Alinity i system. The % cross-reactivity results are shown below.
- Clinical and Laboratory Standards Institute (CLSI). Interference Testing in Clinical Chemistry. 3rd ed. CLSI Guideline EP07. Wayne, PA: CLSI; 2018.
22
| Cross-Reactant | Cross-Reactant Concentration | % Cross-Reactivity (95% CI) |
|---|---|---|
| Desmin | 130,000 pg/mL | 0.0% |
| (0.0%, 0.0%) | ||
| Internexin | 80,000 pg/mL | 0.0% |
| (0.0%, 0.0%) | ||
| Keratin type II | 12,000 pg/mL | 0.0% |
| (0.0%, 0.0%) | ||
| Neurofilament light | 70 pg/mL | -0.4% |
| (-0.5%, -0.2%) | ||
| Neurofilament medium | 9000 pg/mL | 0.0% |
| (0.0%, 0.0%) | ||
| Neurofilament heavy | 80,000 pg/mL | 0.0% |
| (0.0%, 0.0%) | ||
| Peripherin | 6000 pg/mL | 0.0% |
| (0.0%, 0.0%) | ||
| Vimentin | 360,000 pg/mL | 0.0% |
| (0.0%, 0.0%) |
UCH-L1
A study was performed based on guidance from CLSI EP07, 3rd ed.* A sample containing the cross-reactant listed below was prepared in UCH-L1 depleted plasma and tested with the UCH-L1 assay on the Alinity i system. The % cross-reactivity results are shown below.
| Cross-Reactant | Cross-Reactant Concentration | % Cross-Reactivity (95% CI) |
|---|---|---|
| Ubiquitin carboxyl-terminal | ||
| hydrolase L3 (UCH-L3) | 360,000 pg/mL | 0.0% |
| (0.0%, 0.0%) |
- Clinical and Laboratory Standards Institute (CLSI). Interference Testing in Clinical Chemistry. 3rd ed. CLSI Guideline EP07. Wayne, PA: CLSI; 2018.
23
F. Tube Type
A study was performed to evaluate the suitability of specific blood collection tube types for use with the GFAP and UCH-L1 assays. Samples were collected/obtained from a minimum of 70 donors and evaluated across tube types. The following blood collection tube types were determined to be acceptable for use with the GFAP and UCH-L1 assays:
| Specimen Types | Collection Tubes |
|---|---|
| Serum | Serum |
| Serum separator | |
| Plasma | Dipotassium EDTA |
| Tripotassium EDTA | |
| Lithium heparin | |
| Lithium heparin separator |
G. Expected Values (Reference Intervals) (GFAP, UCH-L1, TBI)
Representative performance data are provided in this section. Results obtained in individual laboratories may vary.
A reference interval study was performed based on guidance from CLSI C28-A3c* with a US-based general population from apparently healthy individuals (≥ 18 years old). The specimens were tested with both the GFAP and UCH-L1 assays on the Alinity i system. Based on the results, a 95% reference interval of an apparently healthy population of each assay was determined to be as follows:
| Assay | n | Mean
(pg/mL, ng/L) | SD | Median
(pg/mL, ng/L) | Reference Interval
(2.5th to 97.5th Percentile)
(pg/mL, ng/L) |
|--------|-----|-----------------------|-------|-------------------------|---------------------------------------------------------------------|
| GFAP | 160 | 23.5 | 13.79 | 20.5 | 6.6, 70.9 |
| UCH-L1 | 160 | 108.1 | 45.28 | 98.0 | 44.7, 226.8 |
Clinical and Laboratory Standards Institute (CLSI). Defining, Establishing, and Verifying Reference Intervals in the Clinical Laboratory; Approved Guideline—Third Edition. CLSI Document C28-A3c. Wayne, PA: CLSI; 2008.
24
The TBI interpretation based on the GFAP and UCH-L1 results shown above for apparently healthy individuals (≥ 18 years old) are summarized below.
| GFAP Result
(Relative to Cutoff of
35.0 pg/mL)a | UCH-L1 Result
(Relative to Cutoff
of 400.0 pg/mL)a | TBI
Interpretation | N (Percentage) |
|-------------------------------------------------------|----------------------------------------------------------|-----------------------|-----------------------|
| Above | Above | Positive | 0 (0/160 = 0.0%) |
| Below | Above | Positive | 0 (0/160 = 0.0%) |
| Above | Below | Positive | 21 (21/160 = 13.1%)b |
| Below | Below | Negative | 139 (139/160 = 86.9%) |
a Above means greater than or equal to the cutoff. Below means less than the cutoff.
b Although 13.1% of an apparently healthy population was found to have a positive TBI interpretation, it is important to note GFAP and UCH-L1 cutoffs were optimized in a population of patients with head injury.
H. Specimen Storage
A study was performed to evaluate serum and plasma specimens when subjected to various conditions (2 to 8°C storage, room temperature [15 to 25°C], -20°C or colder) and tested with GFAP and UCH-L1 assays.
The results support the use of serum and plasma specimens that have been stored at the following conditions:
- Room temperature (15 to 25°C) for up to 8 hours on or off the clot, red blood cells, . or separator gel.
- 2 to 8°C for up to 8 hours on the clot, red blood cells, or separator gel and up to . 7 days off the clot, red blood cells, or separator gel. Note: Recentrifuge after 8 hours of storage.
- . -20°C or colder for up to 1 month off the clot, red blood cells, or separator gel with up to 1 freeze/thaw.
I. Assay Cutoff
The assay cutoffs were determined by analyzing a training set with GFAP and UCH-L1 results from a total of 354 with 132 CT positive subjects with suspected mild traumatic brain injury (TBI; Glasgow Coma Scale score of 13-15). Subjects who had blood drawn within 12 hours of injury, a head CT scan determination, and were 18 years or older at
25
the time of injury were included in the analysis. Using a 10-fold cross validation and bootstrapping method, the cutoff values of 35.0 pg/mL (GFAP assay) and 400.0 pg/mL (UCH-L1 assay) were selected for the Alinity i using the selection criteria with an adjusted Negative Predictive Value (NPV) (prevalence 6%) ≥ 99%, sensitivity ≥ 96% and specificity > 37%.
VIII. Summary of Clinical Performance
A. System Reproducibility
GFAP
A study was performed based on guidance from CLSI EP05-A3. Testing was conducted using 3 lots of the GFAP reagents, 3 lots of the GFAP Calibrators, 3 lots of the GFAP Controls, and 1 instrument at each of the 3 testing sites. Three controls and seven human plasma panels (one native panel and six panels supplemented with GFAP analyte) were tested in 4 replicates at 2 separate times per day on 5 different days.
- Clinical and Laboratory Standards Institute (CLSI). Evaluation of Quantitative Measurement Procedures: Approved Guideline—Third Edition. CLSI Document EP05-A3. Wayne, PA: CLSI; 2014.
26
| Sample | N | Mean
(pg/mL,
ng/L) | Within-Run | | Between-Run | | Between-Day | | Between-Lot | | Between-Site | | Overall
Reproducibility* | |
|------------------|-----|--------------------------|------------|-----|-------------|-----|-------------|-----|-------------|-----|--------------|-----|-----------------------------|-----|
| | | | SD | %CV | SD | %CV | SD | %CV | SD | %CV | SD | %CV | SD | %CV |
| Low Control | 360 | 24.9 | 0.61 | 2.4 | 0.18 | 0.7 | 0.57 | 2.3 | 0.26 | 1.1 | 0.37 | 1.5 | 0.97 | 3.9 |
| Medium Control | 360 | 494.6 | 8.33 | 1.7 | 4.46 | 0.9 | 8.06 | 1.6 | 3.46 | 0.7 | 0.94 | 0.2 | 12.93 | 2.6 |
| High Control | 360 | 30520.7 | 630.70 | 2.1 | 404.86 | 1.3 | 230.74 | 0.8 | 252.37 | 0.8 | 428.65 | 1.4 | 928.64 | 3.0 |
| Panel 1 | 360 | 20.4 | 0.61 | 3.0 | 0.26 | 1.3 | 0.53 | 2.6 | 0.19 | 0.9 | 0.34 | 1.7 | 0.94 | 4.6 |
| Panel 2 (Native) | 360 | 37.4 | 0.74 | 2.0 | 0.49 | 1.3 | 0.91 | 2.4 | 0.29 | 0.8 | 0.83 | 2.2 | 1.54 | 4.1 |
| Panel 4 | 360 | 94.9 | 1.66 | 1.8 | 0.89 | 0.9 | 1.87 | 2.0 | 0.00 | 0.0 | 1.26 | 1.3 | 2.94 | 3.1 |
| Panel 5 | 360 | 3072.8 | 50.95 | 1.7 | 33.14 | 1.1 | 43.49 | 1.4 | 17.37 | 0.6 | 11.66 | 0.4 | 77.60 | 2.5 |
| Panel 6 | 360 | 7449.5 | 135.20 | 1.8 | 84.45 | 1.1 | 102.16 | 1.4 | 0.00 | 0.0 | 0.00 | 0.0 | 189.34 | 2.5 |
| Panel 7 | 360 | 15269.2 | 252.80 | 1.7 | 152.99 | 1.0 | 207.63 | 1.4 | 68.84 | 0.5 | 227.57 | 1.5 | 432.38 | 2.8 |
| Panel 8 | 360 | 36101.1 | 852.46 | 2.4 | 368.77 | 1.0 | 568.78 | 1.6 | 781.48 | 2.2 | 1037.82 | 2.9 | 1695.28 | 4.7 |
ª Overall Reproducibility includes within-run, between-day, between-site variance components
27
Qualitative Precision: Results Relative to Cutoff
The GFAP mean (pg/mL), number of results greater than or equal to the cutoff, and % correct call for each GFAP reproducibility panel members and 3 GFAP control levels for all 3 sites are shown in the following table.
| Site | Sample | N | Mean (pg/mL) | # of Result ≥35.0 (pg/mL) / N | % of Correct Calla |
|---|---|---|---|---|---|
| All Sites | Low Controlb | 360 | 24.9 | 0 / 360 | 100.0 |
| Medium Controld | 360 | 494.6 | 360 / 360 | 100.0 | |
| High Controld | 360 | 30,520.7 | 360 / 360 | 100.0 | |
| Panel 1b | 360 | 20.4 | 0 / 360 | 100.0 | |
| Panel 2 (Native)c | 360 | 37.4 | 337 / 360 | 100.0 | |
| Panel 4d | 360 | 94.9 | 360 / 360 | 100.0 | |
| Panel 5d | 360 | 3072.8 | 360 / 360 | 100.0 | |
| Panel 6d | 360 | 7449.5 | 360 / 360 | 100.0 | |
| Panel 7d | 360 | 15,269.2 | 360 / 360 | 100.0 | |
| Panel 8d | 360 | 36,101.1 | 360 / 360 | 100.0 |
a Replicates for positive samples should always be > cutoff, replicates for negative samples should always be * Clinical and Laboratory Standards Institute (CLSI). Evaluation of Quantitative Measurement Procedures: Approved Guideline—Third Edition. CLSI Document EP05-A3. Wayne, PA: CLSI; 2014.
28
| | | Mean | Within-Run | | Between-Run | | Between-Day | | Between-Lot | | Between-Site | | Overall
Reproducibilityª | |
|------------------|-----|------------------|------------|-----|-------------|-----|-------------|-----|-------------|-----|--------------|-----|-----------------------------|-----|
| Sample | N | (pg/mL,
ng/L) | SD | %CV | SD | %CV | SD | %CV | SD | %CV | SD | %CV | SD | %CV |
| Low Control | 360 | 249.9 | 5.83 | 2.3 | 1.63 | 0.7 | 4.85 | 1.9 | 1.62 | 0.6 | 4.29 | 1.7 | 9.01 | 3.6 |
| Medium Control | 360 | 1983.7 | 36.07 | 1.8 | 14.64 | 0.7 | 14.46 | 0.7 | 2.40 | 0.1 | 31.50 | 1.6 | 52.18 | 2.6 |
| High Control | 360 | 14945.1 | 243.83 | 1.6 | 124.28 | 0.8 | 187.94 | 1.3 | 75.42 | 0.5 | 183.94 | 1.2 | 386.96 | 2.6 |
| Panel 1 | 360 | 187.3 | 5.29 | 2.8 | 2.03 | 1.1 | 4.45 | 2.4 | 1.68 | 0.9 | 9.93 | 5.3 | 12.39 | 6.6 |
| Panel 2 (Native) | 360 | 402.4 | 10.91 | 2.7 | 4.55 | 1.1 | 3.58 | 0.9 | 5.52 | 1.4 | 13.24 | 3.3 | 18.93 | 4.7 |
| Panel 4 | 359 | 838.9 | 20.67 | 2.5 | 6.18 | 0.7 | 7.22 | 0.9 | 13.02 | 1.6 | 32.20 | 3.8 | 41.52 | 4.9 |
| Panel 5 | 360 | 1568.0 | 40.83 | 2.6 | 21.71 | 1.4 | 3.97 | 0.3 | 15.74 | 1.0 | 49.33 | 3.1 | 69.54 | 4.4 |
| Panel 6 | 360 | 4792.8 | 125.95 | 2.6 | 48.58 | 1.0 | 61.63 | 1.3 | 23.27 | 0.5 | 112.59 | 2.3 | 187.72 | 3.9 |
| Panel 7 | 360 | 8011.9 | 188.84 | 2.4 | 62.49 | 0.8 | 77.68 | 1.0 | 30.53 | 0.4 | 192.57 | 2.4 | 289.16 | 3.6 |
| Panel 8 | 360 | 19606.6 | 513.60 | 2.6 | 197.00 | 1.0 | 252.28 | 1.3 | 201.66 | 1.0 | 571.99 | 2.9 | 856.78 | 4.4 |
ª Overall Reproducibility includes within-run, between-day, between-lot, and between-site variance components
29
Qualitative Precision: Results Relative to Cutoff
The UCH-L1 mean (pg/mL), number of results greater than or equal to the cutoff, and % correct call for each UCH-L1 reproducibility panel members and 3 UCH-L1 control levels for all 3 sites are shown in the following table.
| Site | Sample | N | Mean (pg/mL) | # of Result ≥ 400.0 (pg/mL) / N | % of Correct Calla |
|---|---|---|---|---|---|
| All Sites | Low Controlb | 360 | 249.9 | 0 / 360 | 100.0 |
| Medium Controld | 360 | 1983.7 | 360 / 360 | 100.0 | |
| High Controld | 360 | 14,945.1 | 360 / 360 | 100.0 | |
| Panel 1b | 360 | 187.3 | 0 / 360 | 100.0 | |
| Panel 2 (Native)c | 360 | 402.4 | 230 / 360 | 100.0 | |
| Panel 4d | 359 | 838.9 | 359 / 359 | 100.0 | |
| Panel 5d | 360 | 1568.0 | 360 / 360 | 100.0 | |
| Panel 6d | 360 | 4792.8 | 360 / 360 | 100.0 | |
| Panel 7d | 360 | 8011.9 | 360 / 360 | 100.0 | |
| Panel 8d | 360 | 19,606.6 | 360 / 360 | 100.0 |
a Replicates for positive samples should always be ≥ cutoff, replicates for negative samples should always be The most common head CT findings in the 120 subjects with CT-positive scans were scalp injury (96.7%), subarachnoid hemorrhage (59.2%), the presence of incidental findings (57.5%), and acute subdural hematoma (47.5%). Other frequently reported findings included cranial fractures (26.7%), parenchymal hematoma (20.0%), facial fractures (16.7%), skull based fractures (15.0%), and indeterminate extra-axial lesions (15.0%). All other findings occurred in less than 10% of CT-positive subjects.
To estimate the clinical performance characteristics, the TBI test interpretation was compared to the adjudicated head CT scan result for each subject. The performance estimates are summarized below. Of the 1899 specimens. 120 had positive CT scan results. Of these 120 specimens, 116 had a positive TBI interpretation (Sensitivity: 96.7%; 95% CI: 91.7%, 98.7%). Four specimens associated with CT scan positive results had a negative TBI interpretation. The rate of False Negative (FN) results was 3.3% (4/120). Five subjects in the study were identified with lesion requiring surgical intervention; none of these five subjects had a FN result, suggesting that the TBI test
34
correctly classified all these five CT-positive subjects with a positive TBI interpretation. Of the 1779 specimens with negative CT scan results, 713 had a negative TBI interpretation (Specificity: 40.1%). The rate of False Positive (FP) results was 59.9% (1066/1779).
Overall, there were 717 specimens with a negative TBI interpretation. Of these, 713 specimens were associated with negative CT scan results. The NPV of the assay was 99.4% (713/717, 95% CI: 98.6%, 99.8%).
The Positive Predictive Value (PPV) of the assay was 9.8%. The Likelihood Ratio Negative (LR-) of the assay was 0.08 (95% CI: 0.03, 0.22). The Likelihood Ratio positive (LR+) of the assay was 1.61 (95% CI: 1.53, 1.70).
| Head CT Scan Result | ||||
|---|---|---|---|---|
| Positive | Negative | Total | ||
| TBI Interpretation | Positive | 116 | 1066 | 1182 |
| Negative | 4 | 713 | 717 | |
| Total | 120 | 1779 | 1899 |
Sensitivity (%) = 96.7 (116 / 120); 95% CI: 91.7, 98.7
Specificity (%) = 40.1 (713 / 1779); 95% CI: 37.8, 42.4
NPV (%)ª=99.4 (713 / 717); 95% CI: 98.6, 99.8
PPV (%) = 9.8 (116 / 1182); 95% CI: 8.2, 11.6
Likelihood Ratio Negative (LR-) = 0.08; 95% CI: 0.03, 0.22
Likelihood Ratio Positive (LR+) = 1.61; 95% CI: 1.53, 1.70
- a Adjusted NPV (%) for 6% CT scan positive prevalence = 99.5; 95% CI: 98.6, 99.8
- b Adjusted PPV (%) for 6% CT scan positive prevalence* = 9.3; 95% CI: 8.9, 9.8
Evaluation of Automatic Class III Designation for Banyan Brain Trauma Indicator. US Food and Drug Administration. Published February 2018. Accessed October 19, 2021 http://www.accessdata.fda.gov/cdrh docs/reviews/DEN170045.pdf
35
| ALERT-TBI study | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Category | Head CT Scan Results | |||||||||||
| Positive | ||||||||||||
| TBI | Negative | |||||||||||
| TBI | Sensitivity | |||||||||||
| (%) (N) | ||||||||||||
| (95% CI) | Specificity | |||||||||||
| (%) (N) | ||||||||||||
| (95% CI) | Adj. | |||||||||||
| PPVa | ||||||||||||
| (%) | ||||||||||||
| (95% CI) | Adj. | |||||||||||
| NPVa | ||||||||||||
| (%) | ||||||||||||
| (95% CI) | LR+ | |||||||||||
| (95% CI) | LR- | |||||||||||
| (95% CI) | ||||||||||||
| All subjects | ||||||||||||
| n = 1899 | Pos | 116 | Neg | 4 | 1066 | 713 | 96.7 (116 / 120) | |||||
| (91.7, 98.7) | 40.1 (713 / 1779) | |||||||||||
| (37.8, 42.4) | 9.3 | |||||||||||
| (8.9, 9.8) | 99.5 | |||||||||||
| (98.6, 99.8) | 1.61 | |||||||||||
| (1.53, 1.70) | 0.08 | |||||||||||
| (0.03, 0.22) | ||||||||||||
| Gender | ||||||||||||
| Male | ||||||||||||
| n = 1073 | ||||||||||||
| (56.5%) | Pos | 68 | Neg | 2 | 601 | 402 | 97.1 (68 / 70) | |||||
| (90.2, 99.2) | 40.1 (402 / 1003) | |||||||||||
| (37.1, 43.1) | 9.4 | |||||||||||
| (8.8, 9.9) | 99.5 | |||||||||||
| (98.2, 99.9) | 1.62 | |||||||||||
| (1.52, 1.73) | 0.07 | |||||||||||
| (0.02, 0.28) | ||||||||||||
| Female | ||||||||||||
| n = 826 | ||||||||||||
| (43.5%) | Pos | 48 | Neg | 2 | 465 | 311 | 96.0 (48 / 50) | |||||
| (86.5, 98.9) | 40.1 (311 / 776) | |||||||||||
| (36.7, 43.6) | 9.3 | |||||||||||
| (8.6, 10.0) | 99.4 | |||||||||||
| (97.6, 99.8) | 1.60 | |||||||||||
| (1.48, 1.74) | 0.10 | |||||||||||
| (0.03, 0.39) | ||||||||||||
| Time from injury to blood draw | ||||||||||||
| 0 - 4 hours | ||||||||||||
| n = 1443 | ||||||||||||
| (76.0%) | Pos | 84 | Neg | 2 | 823 | 534 | 97.7 (84 / 86) | |||||
| (91.9, 99.4) | 39.4 (534 / 1357) | |||||||||||
| (36.8, 42.0) | 9.3 | |||||||||||
| (8.9, 9.8) | 99.6 | |||||||||||
| (98.5, 99.9) | 1.61 | |||||||||||
| (1.53, 1.70) | 0.06 | |||||||||||
| (0.01, 0.23) | ||||||||||||
| > 4 - 8 hours | ||||||||||||
| n = 378 | ||||||||||||
| (19.9%) | Pos | 27 | Neg | 1 | 198 | 152 | 96.4 (27 / 28) | |||||
| (82.3, 99.4) | 43.4 (152 / 350) | |||||||||||
| (38.3, 48.7) | 9.8 | |||||||||||
| (8.8, 10.9) | 99.5 | |||||||||||
| (96.5, 99.9) | 1.70 | |||||||||||
| (1.52, 1.91) | 0.08 | |||||||||||
| (0.01, 0.57) | ||||||||||||
| 0 - 8 hours | ||||||||||||
| n = 1821 | ||||||||||||
| (95.9%) | Pos | 111 | Neg | 3 | 1021 | 686 | 97.4 (111 / 114) | |||||
| (92.5, 99.1) | 40.2 (686 / 1707) | |||||||||||
| (37.9, 42.5) | 9.4 | |||||||||||
| (9.0, 9.8) | 99.6 | |||||||||||
| (98.7, 99.9) | 1.63 | |||||||||||
| (1.55, 1.71) | 0.07 | |||||||||||
| (0.02, 0.20) | ||||||||||||
| > 8 - 12 hours | ||||||||||||
| n = 78 (4.1%) | Pos | 5 | Neg | 1 | 45 | 27 | 83.3 (5 / 6) | |||||
| (43.6, 97.0) | 37.5 (27 / 72) | |||||||||||
| (27.2, 49.0) | 7.8 | |||||||||||
| (5.4, 11.3) | 97.2 | |||||||||||
| (85.2, 99.5) | 1.33 | |||||||||||
| (0.89, 1.99) | 0.44 | |||||||||||
| (0.07, 2.73) |
Performance by gender and time from injury to blood draw is also presented below.
Since specimens from the ALERT-TBI study were archived frozen samples, a specimen stability study was conducted to demonstrate the integrity of clinical samples, as per special control b(1)(ii)(i) of 21 CFR 866.5830. The study demonstrated stability of plasma samples covering a range of GFAP and UCH-L1 antigen levels stored frozen at -70°C°.
The results showed that the clinical performance of the TBI test is characterized by high clinical sensitivity and high NPV comparable to that demonstrated by the Banyan BTI (DEN170045; clinical sensitivity = 97.5%, clinical specificity = 36.5%, NPV = 99.6%, PPV = 9.2%), which supports clinical utility as an aid in the evaluation of the need for a CT scan in subjects presenting with a GCS score of 13 to 15.
36
Attachment B
Fresh Specimen Study
To supplement the results of the pivotal study (N=1899) described above, a study was conducted using freshly collected plasma specimens from consenting men and women 18 years of age or older who presented to a HCF or ED with suspected mild TBI, with initial GCS scores of 13-15, and who had a CT scan of the head performed per the clinical site's standard of care. A total of 97 subjects were enrolled across 5 clinical sites in the United States.
Similar to the pivotal study, CT scans were performed in accordance with the clinical site's standard of care. Images were transmitted to a central neuroimaging processing center. Images were interpreted by at least two radiologists who were masked to other clinical and laboratory data; procedures for scoring images were established before conducting image review. The clinical outcome was based on the consensus interpretation between two radiologists, with adjudication by a third radiologist if necessary. Outcomes were positive, negative, or inconclusive as defined by the presence or absence of acute traumatic intracranial lesions, respectively. Acute intracranial lesion was defined as any trauma induced or related finding visualized upon head CT scan.
Whole blood was collected into dipotassium EDTA blood collection tubes from each subject using venipuncture and centrifuged to obtain plasma. Specimens were collected within 12 hours of head injury. The demographic characteristics of the subjects represented in the performance analysis are summarized below:
| Head CT Scan Result | |||
|---|---|---|---|
| Demographic Characteristics | Positive | Negative | Total |
| N | 14 (14.4%) | 83 (85.6%) | 97 |
| Age (Years) | |||
| Mean (SD) | 41.5 (20.33) | 48.4 (20.24) | 47.4 (20.29) |
| Median | 33.5 | 49.0 | 43.0 |
| Range (minimum, maximum) | (19.0, 73.0) | (18.0, 85.0) | (18.0, 85.0) |
| Gender, N (%) | |||
| Male | 10 (71.4%) | 51 (61.4%) | 61 (62.9%) |
| Female | 4 (28.6%) | 32 (38.6%) | 36 (37.1%) |
| Ethnicity, N (%) |
37
| Demographic Characteristics | Head CT Scan Result | Positive | Negative | Total |
|---|---|---|---|---|
| Hispanic or Latino | 4 (28.6%) | 22 (26.5%) | 26 (26.8%) | |
| Not Hispanic or Latino | 10 (71.4%) | 60 (72.3%) | 70 (72.2%) | |
| Race, N (%) | ||||
| White | 13 (92.9%) | 56 (67.5%) | 69 (71.1%) | |
| Black or African American | 0 (0.0%) | 12 (14.5%) | 12 (12.4%) | |
| Asian | 1 (7.1%) | 7 (8.4%) | 8 (8.2%) | |
| Native Hawaiian or Other Pacific Islander | 0 (0.0%) | 1 (1.2%) | 1 (1.0%) |
The head injury characteristics of the subjects in the supplemental fresh plasma specimen study including information regarding time from head injury to CT scan and head injury to blood draw, as well as GCS, neurological assessment, physical evidence of trauma, and mechanism of injury, categorized by head CT scan results, are shown below.
| Head CT Scan Result | |||
|---|---|---|---|
| Head Injury Characteristics | Positive | Negative | Total |
| N | 14 | 83 | 97 |
| Time from head injury to CT scan (hours) | |||
| Mean (SD) | 2.2 (1.47) | 3.1 (1.76) | 3.0 (1.74) |
| Median | 1.8 | 2.7 | 2.6 |
| Range (minimum, maximum) | (0.8, 6.5) | (0.8, 9.9) | (0.8, 9.9) |
| Time from head injury to blood draw (hours) | |||
| Mean (SD) | 8.4 (2.90) | 5.9 (2.64) | 6.3 (2.81) |
| Median | 8.6 | 5.2 | 5.4 |
| Range (minimum, maximum) | (4.1, 11.8) | (1.4, 12.0) | (1.4, 12.0) |
| GCS score - Number (%) | |||
| 13 | 1 (7.1%) | 0 (0.0%) | 1 (1.0%) |
| 14 | 3 (21.4%) | 4 (4.8%) | 7 (7.2%) |
| 15 | 10 (71.4%) | 79 (95.2%) | 89 (91.8%) |
| Neurological Assessment - Number (%) of subjects experiencing: | |||
| Loss of Consciousness (LOC) | 10 (71.4%) | 31 (37.3%) | 41 (42.3%) |
| Alteration of Consciousness (AOC) | 11 (78.6%) | 51 (61.4%) | 62 (63.9%) |
| Vomiting | 3 (21.4%) | 3 (3.6%) | 6 (6.2%) |
38
| Head CT Scan Result | ||||
|---|---|---|---|---|
| Head Injury Characteristics | Positive | Negative | Total | |
| Post Traumatic Amnesia (PTA) | 10 (71.4%) | 35 (42.2%) | 45 (46.4%) | |
| Subjects with Drug in System at the Time of | ||||
| Presentation to Facility | 5 (35.7%) | 8 (9.6%) | 13 (13.4%) | |
| Subjects with Alcohol in System at the Time of | ||||
| Presentation to Facility | 7 (50.0%) | 6 (7.2%) | 13 (13.4%) | |
| Physical Evidence – N (%) | ||||
| Subdural Hematoma | 10 (71.4%) | 0 (0.0%) | 10 (10.3%) | |
| Subarachnoid Hemorrhage | 10 (71.4%) | 1 (1.2%) | 11 (11.3%) | |
| Acute Skull Fracture | 8 (57.1%) | 1 (1.2%) | 9 (9.3%) | |
| Contusion | 6 (42.9%) | 0 (0.0%) | 6 (6.2%) | |
| Intracerebral Hemorrhage | 1 (7.1%) | 0 (0.0%) | 1 (1.0%) | |
| Epidural Hematoma | 1 (7.1%) | 0 (0.0%) | 1 (1.0%) | |
| Traumatic Axonal Injury | 1 (7.1%) | 0 (0.0%) | 1 (1.0%) | |
| Midline Shift Supratentorial | 2 (14.3%) | 0 (0.0%) | 2 (2.1%) | |
| Cisternal Compression | 2 (14.3%) | 0 (0.0%) | 2 (2.1%) | |
| Edema | 1 (7.1%) | 0 (0.0%) | 1 (1.0%) | |
| Brain Atrophy or Encephalomalacia | 0 (0.0%) | 2 (2.4%) | 2 (2.1%) | |
| Brain Swelling | 2 (14.3%) | 0 (0.0%) | 2 (2.1%) | |
| Visible Trauma Above the Clavicle | 13 (92.9%) | 55 (66.3%) | 68 (70.1%) | |
| Signs of Basal Skull Fracture | 2 (14.3%) | 0 (0.0%) | 2 (2.1%) | |
| Mechanism of Injury – N (%) | ||||
| Acceleration/Deceleration | 2 (14.3%) | 26 (31.3%) | 28 (28.9%) | |
| Direct impact: Blow to Head | 4 (28.6%) | 13 (15.7%) | 17 (17.5%) | |
| Direct impact: Head Against Object | 11 (78.6%) | 54 (65.1%) | 65 (67.0%) | |
| Fall from height > 1 meter (3 ft) | 2 (14.3%) | 4 (4.8%) | 6 (6.2%) | |
| Ground level fall | 4 (28.6%) | 26 (31.3%) | 30 (30.9%) |
The TBI test on the Alinity i system clinical performance estimates from the supplemental plasma fresh specimen study are shown below. Of the 97 subjects tested, 14 had positive head CT scan results. Of these 14 subjects, 14 had a positive TBI test interpretation (14 / 14, clinical sensitivity = 100.0%). The rate of False Negatives (FN) was 0.0% (0 / 14). Of the 83 subjects associated with negative CT scan results, 23 had a negative TBI test interpretation (23 / 83, clinical specificity =27.7%). The rate of False Positive (FP) results was 72.3% (60 / 83).
39
Overall, there were 23 specimens with a negative TBI test interpretation. All
23 specimens were associated with negative head CT scan results. The NPV of the assay was 100.0% (23 / 23).
| Head CT Scan Result | |||
|---|---|---|---|
| TBI Interpretation | Positive | Negative | Total |
| Positive | 14 | 60 | 74 |
| Negative | 0 | 23 | 23 |
| Total | 14 | 83 | 97 |
Sensitivity (%) = 100.0 (14 / 14); 95% CI: 78.5, 100.0
Specificity (%) = 27.7 (23 / 83); 95% CI: 19.2, 38.2
NPV (%)ª = 100.0 (23 / 23); 95% CI: 85.7, 100.0
PPV (%)ª = 18.9 (14 / 74); 95% CI: 11.6, 29.3
Likelihood Ratio Negative (LR-) = 0.12; 95% CI: 0.01, 1.91
Likelihood Ratio Positive (LR+) = 1.38; 95% CI: 1.21, 1.58
- a NPV and PPV are estimated at 14.43% prevalence of CT scan positive rate for suspected mild TBI subjects in the fresh study. If NPV and PPV are adjusted to 6% prevalence rate (comparable to the pivotal study cohort), NPV = 99.2% (95% CI: 89.1,99.9), and PPV = 8.1 (95% CI: 7.2, 9.1)
The results show that the TBI test, when evaluated with fresh plasma samples, is characterized by high sensitivity and NPV supportive of its clinical utility as an aid in the evaluation of the need for a CT scan in subjects presenting with a GCS score of 13 to 15.
IX. Conclusion
The information presented in this 510(k) premarket notification demonstrate that the subject device, TBI for use with Alinity i, is substantially equivalent to the predicate device, Banyan BTI (DEN170045), and meets special controls requirements of 21 CFR 866.5830.
Evaluation of Automatic Class III Designation for Banyan Brain Trauma Indicator. US Food and Drug Administration. Published February 2018. Accessed October 19, 2021 http://www.accessdata.fda.gov/cdrh_docs/ reviews/DEN170045.pdf