(223 days)
The IMMULITE® 2000 TSI (thyroid-stimulating immunoglobulins) Assay is an in vitro diagnostic immunoassay for the semi-quantitative determination of thyroid stimulating autoantibodies specific to thyroid stimulating hormone receptors (TSHR) in human serum (including Serum Separator tubes) or plasma (K2-EDTA or lithium heparin). The IMMULITE® 2000 TSI Assay is for use on the IMMULITE® 2000 system. The measurement of thyroid stimulating autoantibodies, in conjunction with other clinical and laboratory findings, is used as an aid in the diagnosis of patients suspected of having Graves' disease.
The IMMULITE® TSI Calibration Verification Material (CVM) is for in vitro diagnostic use in the verification of calibration of the IMMULITE® TSI Assay on the IMMULITE® 2000 Systems.
The IMMULITE 2000 TSI assay kit consists of the following components:
- TSI bead pack coated with MAb (3D7) anti-TSHR anchor antibody and hTSHR Capture Chimera
- TSI reagent wedge containing hTSHR-Chimera alkaline phosphatase conjugate
- TSI adjustors: low and high, containing TSI negative heat-inactivated bovine serum and thyroid stimulating human MAb (M22)
- TSI controls: negative, low, and high, containing TSI negative human serum and thyroid stimulating MAb (M22)
- Multi-Diluent 2
Here's a breakdown of the acceptance criteria and the study that proves the device meets them, based on the provided text:
1. Table of Acceptance Criteria and Reported Device Performance
The acceptance criteria are generally implied from the "Drift Specifications" for stability and the statistical measures for precision and method comparison. The device performance is the "reported performance".
| Performance Characteristic | Acceptance Criteria (Implied/Stated) | Reported Device Performance |
|---|---|---|
| Precision/Reproducibility | Not explicitly stated numerical acceptance criteria for %CV, but generally clinical assays aim for low %CVs. | 20-Day Imprecision:- Repeatability %CV: Ranged from 3.5% to 7.0%.- Within Lab %CV: Ranged from 5.0% to 8.3%. |
| Linearity/Reportable Range | Linearity data for % Difference to be ± 15% or 0.50 IU/L (whichever is greater). | Linearity data for % Difference was shown to be ± 15% or 0.50 IU/L (whichever is greater) for most samples; tested within range 0.50 - 40.0 IU/L. |
| Assay/Component Stability Drift | Reagents and Beads: - Control 1 at ≤ -60°C: ≤ 15% from Day 0 mean - Control 2 at ≤ -60°C: ≤ 10% from Day 0 mean - CVM 1 at ≤ -60°C: ≤ 0.15 IU/L from Day 0 mean - MDP 1: ≤ 20% from Day 0 mean - MDP 4: ≤ 10% from Day 0 mean - Cal J: ≤ 10% from Day 0 mean (Also, all Control results must be within QC established range to validate the run). | Stability Claims Achieved: - Kit, unopened: 12 Months (2-8 °C) - Bead Pack, open: 90 Days (2-8 °C) - Reagent wedge, open and on-board: 90 Days (2-8 °C) - Sample diluent, open: 30 Days (2-8 °C) - Sample diluent, open frozen aliquotted: 6 Months (-20 °C) - Adjustors open: 90 Days (2-8 °C) - Adjustors frozen aliquotted: 4 Months (-20 °C) - Controls open: 90 Days (2-8 °C) - Controls frozen aliquotted: 6 Months (-20 °C) - CVM, unopened: 12 Months (2-8 °C) - CVM, opened and reconstituted: 30 Days (2-8 °C) Sample Stability: 24 hours at 20-25°C, 7 days at 2-8°C, and 12 months at -20°C for serum and plasma. |
| Limit of Blank (LoB) | LoB should be low enough for clinical utility. | Highest LoB by lot was determined to be 0.03 IU/L. |
| Limit of Detection (LoD) | LoD should be low enough for clinical utility. | Highest LoD by lot was determined to be 0.06 IU/L. |
| Analytical Specificity (Interference) | No interference (≤ 10% different than control sample). | Interferents (Intralipid, Hemoglobin, Bilirubin, K2-EDTA): No interference (≤ 10% difference) except for hemoglobin (≥ 200mg/dL potentially affects recovery) and short draw K2-EDTA (may result in under-recovery). HAMA: Individual sample bias of <4% (at 10ng/mL and 40ng/mL HAMA). Rheumatoid Factor (RF): Individual sample bias of <5% (at 100 IU/mL and 200 IU/mL RF). Cross-Reactivity (TSH, FSH, LH, hCG, aTPO, and aTG): Bias of ≤10% for all interferents and samples. |
| Method Comparison (vs. Thyretain TSI Reporter BioAssay) | High agreement (generally >90% for positive, negative, and overall). | Positive Agreement: 95.8% (95% CI: 93.0 – 97.7) Negative Agreement: 87.7% (95% CI: 84.5 - 90.5) Overall Agreement: 91.0% (95% CI: 88.8 - 92.9) |
| Matrix Comparison (Regression Coefficient) | Strong correlation (e.g., R-value > 0.95 or 0.98). | SST Serum: Slope 1.01, Intercept 0.00, Correlation Coefficient 0.99 K2-EDTA Plasma: Slope 1.03, Intercept -0.01, Correlation Coefficient 0.99 Lithium Heparin Plasma: Slope 0.99, Intercept -0.01, Correlation Coefficient 0.99 |
| Clinical Sensitivity and Specificity (at 0.55 IU/L cut-off) | High clinical sensitivity and specificity (generally >95%). | Clinical Sensitivity: 98.6% (95% CI: 96.8 – 99.5) Clinical Specificity: 98.5% (95% CI: 96.8 – 99.5) |
| Reference Range (97.5th percentile) | Clinically appropriate range. | < 0.10 IU/L (using non-parametric 97.5th percentile). |
*Specific Answers to Questions:
2. Sample size used for the test set and the data provenance (e.g. country of origin of the data, retrospective or prospective)
- Precision/Reproducibility: 6 serum samples and low/high kit controls, tested in duplicate in two runs per day over 20 days (total 80 replicates per sample). Data provenance not specified (likely internal laboratory data, prospective for the study).
- Linearity: TSI positive and TSI negative samples from "several commercial vendors." Data provenance not specified.
- LoB: 5 TSI negative samples, tested with 3 reagent lots, 2 runs, 2 replicates per run for 3 days (total >180 measurements). Data provenance not specified.
- LoD: 5 TSI serum samples, tested in 4 replicates using 3 reagent kit lots for 3 days on 3 systems (total 36 observations per sample). Data provenance not specified.
- Analytical Specificity (Interference): Three serum pools (for endogenous interferents), HAMA positive serum, RF positive serum, and six potential biological interferent samples. Data provenance not specified.
- Method Comparison: 811 serum samples from patients with Graves' disease, other thyroid or autoantibody diseases. Specimens tested at two external sites and one internal site for the IMMULITE 2000 TSI assay, and at one external site for the Thyretain device. Data provenance not explicitly stated, but implies mixed sources (internal/external, likely retrospective patient samples).
- Matrix Comparison: Graves' Disease sets of matched serum and plasma samples (clot tube, lithium heparin, SST, K2-EDTA). Sample size not specified. Data provenance not specified.
- Clinical Sensitivity and Specificity: 361 treated and untreated hyperthyroid Graves' disease patients and 404 individuals with other thyroid or autoimmune diseases. Data provenance not specified (likely retrospective clinical samples).
- Reference Range: 842 serum samples from apparently healthy males (n=151), non-pregnant females (n=155), first trimester (n=169), second trimester (n=191), and third trimester (n=176) pregnant donors. Data provenance not specified.
3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts (e.g. radiologist with 10 years of experience)
The document does not specify the number or qualifications of experts used to establish the ground truth for any of the test sets. For example, for clinical sensitivity and specificity, it refers to "Graves' Disease Diagnosis" and "other thyroid or autoimmune diseases" but does not detail how these diagnoses were definitively established or by whom. Similarly, for the method comparison, it refers to patient samples for Graves' disease or other thyroid/autoantibody diseases without detailing expert adjudication of these conditions.
4. Adjudication method (e.g. 2+1, 3+1, none) for the test set
The document does not describe any specific adjudication method for establishing ground truth diagnoses for the patient samples used in the studies. The diagnoses are simply stated as existing, implying they were pre-determined or established through typical clinical practice, rather than through a separate expert adjudication process for the study.
5. If a multi reader multi case (MRMC) comparative effectiveness study was done, If so, what was the effect size of how much human readers improve with AI vs without AI assistance
No, a multi-reader multi-case (MRMC) comparative effectiveness study was not done. This is an immunoassay device, not an imaging AI device that involves human readers interpreting cases. The comparison study was a "Method Comparison" between the new Immulite 2000 TSI assay and a predicate immunoassay device (Thyretain TSI Reporter BioAssay), analyzing patient samples.
6. If a standalone (i.e. algorithm only without human-in-the-loop performance) was done
Yes, the studies presented are all standalone validations of the Immulite 2000 TSI assay system. It is an automated immunoassay for in vitro diagnostic use, meaning it provides results directly from patient samples without human interpretation of images or other complex data requiring "human-in-the-loop" decision-making. The performance characteristics (precision, linearity, detection limits, clinical sensitivity/specificity, etc.) reflect the algorithm/device's performance alone.
7. The type of ground truth used (expert consensus, pathology, outcomes data, etc)
The ground truth for the clinical studies (clinical sensitivity/specificity, method comparison) appears to be clinical diagnosis of Graves' disease or other thyroid/autoimmune diseases. For analytical performance studies (precision, linearity, LoB, LoD, interference), the ground truth is based on spiking known concentrations, using negative samples, or established reference standards like the NIBSC standard.
8. The sample size for the training set
The document does not explicitly mention a "training set" in the context of machine learning. This is a traditional immunoassay, not an AI device that typically involves distinct training and test sets in the same manner. The studies describe validation sets, not training sets for model development.
9. How the ground truth for the training set was established
As there is no distinct "training set" in the context of an AI/machine learning model as understood in typical AI/ML submissions, this question is not directly applicable. For traditional assays, calibrators are used to establish the measurement and are themselves calibrated against reference materials (e.g., NIBSC standard 08/204 for the Immulite 2000 TSI assay).
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Image /page/0/Picture/1 description: The image shows the logo for the Department of Health & Human Services - USA. The logo consists of a circular seal with the text "DEPARTMENT OF HEALTH & HUMAN SERVICES - USA" arranged around the perimeter. Inside the circle is a stylized image of three human profiles facing to the right, with flowing lines representing hair or movement.
March 3, 2016
Food and Drug Administration 10903 New Hampshire Avenue Document Control Center - WO66-G609 Silver Spring, MD 20993-0002
Siemens Healthcare Diagnostics, Inc. Susan Brocchi Regulatory Clinical Affairs Specialist 511 Benedict Avenue Tarrytown NY 10591
Re: K152061
Trade/Device Name: Immulite 200 TSI Assay, Immulite 200 TSI Calibration Verification Material
Regulation Number: 21 CFR 866.5870 Regulation Name: Thyroid autoantibody immunological test system Regulatory Class: II Product Code: JZO Dated: February 3, 2016 Received: February 4, 2016
Dear Ms. Brocchi:
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. 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 requirements, including, but not limited to: registration and listing (21 CFR Part 807); labeling (21 CFR Parts 801 and 809); medical device reporting (reporting of medical device-related adverse events) (21 CFR 803); good manufacturing practice requirements as set forth in the quality systems (OS) regulation (21 CFR Part 820); and if applicable, the electronic product radiation control provisions (Sections 531-542 of the Act); 21 CFR 1000-1050.
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If you desire specific advice for your device on our labeling regulations (21 CFR Parts 801 and 809), please contact the Division of Industry and Consumer Education at its toll-free number (800) 638 2041 or (301) 796-7100 or at its Internet address
http://www.fda.gov/MedicalDevices/ResourcesforYou/Industry/default.htm. 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
http://www.fda.gov/MedicalDevices/Safety/ReportaProblem/default.htm for the CDRH's Office of Surveillance and Biometrics/Division of Postmarket Surveillance.
You may obtain other general information on your responsibilities under the Act from the Division of Industry and Consumer Education at its toll-free number (800) 638-2041 or (301) 796-7100 or at its Internet address
http://www.fda.gov/MedicalDevices/ResourcesforYou/Industry/default.htm.
Sincerely yours,
Kelly OlinerAS
For.
Leonthena R. Carrington, MS, MBA, MT(ASCP) Director Division of Immunology and Hematology Devices Office of In Vitro Diagnostics and Radiological Health Center for Devices and Radiological Health
Enclosure
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Indications for Use
510(k) Number (if known) K152061
Device Name IMMULITE®2000 TSI Assay
IMMULITE®2000 TSI Calibration Verification Material (CVM)
Indications for Use (Describe)
The IMMULITE® 2000 TSI (thyroid-stimulating immunoglobulins) Assay is an in vitro diagnostic immunoassay for the semi-quantitative determination of thyroid stimulating autoantibodies specific to thyroid stimulating hormone receptors (TSHR) in human serum (including Serum Separator tubes) or plasma (K2-EDTA or lithium heparin). The IMMULITE® 2000 TSI Assay is for use on the IMMULITE® 2000 system. The measurement of thyroid stimulating autoantibodies, in conjunction with other clinical and laboratory findings, is used as an aid in the diagnosis of patients suspected of having Graves' disease.
The IMMULITE® TSI Calibration Material (CVM) is for in vitro diagnostic use in the verification of calibration of the IMMULITE® TSI Assay on the IMMULITE® 2000 Systems.
X Prescription Use (Part 21 CFR 801 Subpart D)
Over-The-Counter Use (21 CFR 801 Subpart C)
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IMMULITE® 2000 TSI Assay
510(k) Summary as Required by 21 CFR 807.92
A. 510(k) Number:
- B. Purpose for Submission: New Device
- C. Measurand: Thyroid-stimulating immunoglobulins
- D. Type of test: Semi-quantitative chemiluminescent immunometric assay
- E. Applicant: Siemens Laboratory Diagnostics Inc.
- F. Proprietary and Established Names: IMMULITE®2000 TSI Assay IMMULITE®2000 TSI Calibration Verification Material
- G. Regulatory Information:
| Regulation Section | Classification | Product Code | Panel |
|---|---|---|---|
| 21 CFR 866.5870,Thyroid autoantibodyimmunological testsystem | Class 2 (PerformanceStandards) | JZO – System, Test,Thyroid Autoantibody | Immunology (82) |
| 21 CFR 862.1150 | Class 2 | JIT, Calibrator,secondary | Clinical Chemistry(75) |
| 21 CFR 862.1660,Quality controlmaterial (assayed andunassayed) | Class 1, reserved | JJX, Single analytecontrol | Clinical Chemistry(75) |
H. Intended Use:
-
- Intended use(s):
The IMMULITE® 2000 TSI (thyroid-stimulating immunoglobulins) Assay is an in vitro diagnostic immunoassay for the semi-quantitative determination of thyroid stimulating autoantibodies specific to thyroid stimulating hormone receptors (TSHR) in human serum (including Serum Separator tubes) or plasma (K2-EDTA or lithium heparin). The IMMULITE® 2000 TSI Assay is for use on the IMMULITE® 2000 system. The measurement of thyroid stimulating autoantibodies, in conjunction with other clinical and laboratory findings, is used as an aid in the diagnosis of patients suspected of having Graves' disease.
- Intended use(s):
The IMMULITE® TSI Calibration Verification Material (CVM) is for in vitro diagnostic
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use in the verification of calibration of the IMMULITE® TSI Assay on the IMMULITE® 2000 Systems.
-
- Indication(s) for use: See Intended Use above
-
- Special conditions for use statement(s): For prescription use only
-
- Special instrument requirements: Only for use on the IMMULITE 2000 Analyzer (K970227)
I. Device Description:
The IMMULITE 2000 TSI assay kit consists of the following components:
- TSI bead pack coated with MAb (3D7) anti-TSHR anchor antibody and hTSHR Capture Chimera
- TSI reagent wedge containing hTSHR-Chimera alkaline phosphatase conjugate
- TSI adjustors: low and high, containing TSI negative heat-inactivated bovine serum and ● thyroid stimulating human MAb (M22)
- TSI controls: negative, low, and high, containing TSI negative human serum and thyroid stimulating MAb (M22)
- Multi-Diluent 2 ●
J. Substantial Equivalence Information:
-
- Comparison with predicate:
| ASSAY SIMILARITIES – Predicate 1 | ||
|---|---|---|
| Item | Device | Predicate 1 |
| IMMULITE 2000 TSI Assay | Thyretain TSI Reporter BioAssay | |
| Analyte | TSH receptor stimulatingautoantibodies | same |
| Signal | Chemiluminescence | same |
| Detectionmethod | Luminometry | same |
| Controls | 3 (negative, low, and high) | 3 (negative, reference, positive) |
| ASSAY DIFFERENCES – Predicate 1 | ||
| Item | Device | Predicate |
| IMMULITE® 2000 TSI Assay | Thyretain TSI Reporter BioAssay |
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| Intended Use | The IMMULITE® 2000 TSI(thyroid-stimulatingimmunoglobulins) Assay is an invitro diagnostic immunoassay forthe semi-quantitative determinationof thyroid stimulating autoantibodiesspecific to thyroid stimulatinghormone receptors (TSHR) inhuman serum (including SerumSeparator tubes) or plasma (K2-EDTA or lithium heparin). TheIMMULITE® 2000 TSI Assay is foruse on the IMMULITE® 2000system. The measurement of thyroidstimulating autoantibodies, inconjunction with other clinical andlaboratory findings, is used as an aidin the diagnosis of patientssuspected of having Graves' disease. | Intended for the qualitative detectionin serum of thyroid stimulatingautoantibodies to the thyroidstimulating hormone receptors(TSHRs) on the thyroid. The detectionof these stimulating autoantibodies, inconjunction with other clinical andlaboratory findings, may be useful asan aid in the differential diagnosis ofpatients with Graves' disease. |
|---|---|---|
| Assay Principal | Immunometric | Cell-based Bioassay |
| Sample matrix | Serum or plasma | Serum |
| Assay format | Semi-quantitative | Qualitative |
| Unit of measure | IU/L | SRR% (sample to reference ratio) |
| Solid phase | Polystyrene bead coated withhTSHR capture chimera | CHO Mc4 cell monolayer |
| Traceability | NIBSC Standard 08/204 | NISBC Standard 03/192 |
| Sample size | 50 uL | 40 uL |
| Measuringrange | 0.10-40 IU/L | N/A (qualitative) |
| Incubation time | 60 minutes | 3 hours |
| LoB | 0.03 IU/L | 62.75% |
| LoD | 0.06 IU/L | 89.14% |
| Assay Cut-off | 0.55 IU/L | 140% |
| ASSAY SIMILARITIES – Predicate 2 | ||
|---|---|---|
| Item | Device | Predicate 2 |
| IMMULITE 2000 TSI Assay | Elecsys Anti-TSHR Immunoassay | |
| Analyte | TSH receptor stimulatingautoantibodies | Same |
| Unit ofmeasure | IU/L | Same |
| Sample size | 50μL | Same |
| ASSAY DIFFERENCES – Predicate 2 | ||
| Item | Device | Predicate |
| IMMULITE® 2000 TSI Assay | Elecsys Anti-TSHR Immunoassay | |
| Intended Use | The IMMULITE® 2000 TSI (thyroid-stimulating immunoglobulins) Assay is an in vitro diagnostic immunoassay for the semi-quantitative determination of thyroid stimulating autoantibodies specific to thyroid stimulating hormone receptors (TSHR) in human serum (including Serum Separator tubes) or plasma (K2-EDTA or lithium heparin). The IMMULITE® 2000 TSI Assay is for use on the IMMULITE® 2000 system. The measurement of thyroid stimulating autoantibodies, in conjunction with other clinical and laboratory findings, is used as an aid in the diagnosis of patients suspected of having Graves' disease. | An immunoassay for the in vitro quantitative determination of autoantibodies to TSH receptor in human serum using a human thyroid stimulating monoclonal antibody. The anti-TSH receptor determination is used in the assessment of patients with suspect Graves' disease (autoimmune hyperthyroidism). The electrochemiluminescence immunoassay “ECLIA” is intended for use on Elecsys and cobas e immunoassay analyzers. |
| Sample matrix | Serum or plasma | Serum |
| Controls | 3 (negative, low, and high) | 2 (positive and negative) |
| DetectingAntibody | hTSHR AP detection Chimera | M22 |
| Assay Protocol | Bridge Format | Competition Principle |
| DetectionProtocol | Chemiluminescence | Electrochemiluminescence |
| Traceability | NIBSC Standard 08/204 | NISBC Standard 90/672 |
| Incubation | 60 Minutes | 27 Minutes |
| LoB | 0.03 IU/L | 0.500 IU/L |
| LoD | 0.06 IU/L | 0.800 IU/L |
| LoQ | 0.10 IU/L | 0.900 IU/L |
| ReportableRange | 0.10-40 IU/L | 0.800 - 40.0 IU/L |
| Assay Cut-off | 0.55 IU/L | 1.75 IU/L |
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| Calibrator Verification Materials | ||
|---|---|---|
| SIMILARITIES | ||
| Item | Device | Predicate |
| IMMULITE® 2000 TSI CVM | Elecsys Anti-TSHR CalCheck | |
| Form | Lyophilized | Same |
| Stability | Stable unopened until the expiration date. | Same |
| Use | Single Use Only | Same |
| Analyte | Thyroid Stimulating IgG | Same |
| Storage | 2-8°C | Same |
| Calibrator Verification Materials | ||
| DIFFERENCES | ||
| Item | Device | Predicate |
| IMMULITE® 2000 TSI CVM | Elecsys Anti-TSHR CalCheck | |
| Intended Use | The IMMULITE® TSI Calibration Verification Material (CVM) is for in vitro diagnostic use in the verification of calibration of the IMMULITE® TSI Assay on the IMMULITE® 2000 Systems. | For use in the verification of calibration established by the Elecsys Anti-TSHR reagent on the indicated Elecsys and cobas e immunoassay analyzers. |
| Instrumentation | Siemens IMMULITE® 2000 | Roche Elecsys and cobas e |
| Sample Matrix | Bovine serum with preservatives | Human serum |
K. Standard/Guidance Documents Referenced:
CLSI EP05-A2, Evaluation of Precision Performance of Quantitative Measurement Methods, Approved Guideline – Second Edition
CLSI EP06-A, Evaluation of Linearity of Quantitative Measurement Methods: A Statistical Approach – First Edition
CLSI EP07-A2, Interference Testing in Clinical Chemistry; Approved Guideline - Second Edition
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CLSI EP09-A3, Measurement Procedure Comparison and Bias Estimation Using Patient Samples - Third Edition
CLSI EP17-A2, Evaluation of Detection Capability for Clinical Laboratory Measurement Procedures: Approved Guideline - Second Edition
CLSI EP24-A2, Assessment of the Diagnostic Accuracy of Laboratory Tests Using Receiver Operating Characteristic Curves; Approved Guideline - Second Edition
CLSI EP25-A, Evaluation of Stability of in vitro Diagnostic Reagents; Approved Guidance – First Edition
CLSI EP28-A3c, Defining, Establishing, and Verifying Reference Intervals in the Clinical Laboratory – Third Edition
L. Test Principle:
The IMMULITE 2000 TSI assay is an automated, two-cycle, chemiluminescent immunoassay. It employs two recombinant chimeric human TSH receptors (hTSHR) where the major epitope for the blocking antibody is replaced. The capture receptor is immobilized on the solid phase (polystyrene bead) by 3D7, a monoclonal antibody directed against the C-terminus of hTSHR. In the first 30-minute cvcle, thyroid stimulating antibodies in the patient sample bind through one arm to the capture receptor on the polystyrene bead. Upon completion of the 1st cycle, the bead is washed 4X with water onboard the instrument. In the second cycle, a liquid reagent containing the signal receptor is added to the reaction tube and incubated for 30-minutes. The immobilized TSI binds the signal receptor through the second arm forming a bridge. Unbound signal receptor is then removed by four centrifugal water washes. Finally, chemiluminescent substrate is added to the reaction tube and a signal is generated in direct relation to the amount of bound signal receptor and TSI in the sample.
M. Performance Characteristics
-
- Analytical Performance:
- a. Precision/Reproducibility:
Precision was evaluated using a protocol based on CLSI document EP05-A2. Six serum samples and the low and high kit controls were tested. Serum samples were prepared by mixing positive samples into negative sample pools in order to reach the desired concentration.
Each sample was tested in duplicate in two runs per day over 20 days, for a total of 80 replicates. One instrument was used, and one lot of the device was tested for a total of 80 replicates per sample. Precision was calculated using Nested Analysis of Variance.
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| 20-DayImprecisionN=80 | Repeatability | Within Lab | |||
|---|---|---|---|---|---|
| Sample | MeanIU/L | SD | %CV | SD | %CV |
| L2SIC1 | 1.04 | 0.05 | 4.9 | 0.06 | 5.4 |
| L2SIC2 | 21.27 | 0.96 | 4.5 | 1.21 | 5.7 |
| SERP1 | 0.34 | 0.02 | 7.0 | 0.03 | 8.3 |
| SERP2 | 0.69 | 0.03 | 4.1 | 0.03 | 5.0 |
| SERP3 | 1.57 | 0.07 | 4.4 | 0.08 | 5.3 |
| SERP4 | 4.43 | 0.18 | 4.0 | 0.26 | 5.9 |
| SERP5 | 7.80 | 0.27 | 3.5 | 0.42 | 5.4 |
| SERP6 | 29.09 | 1.91 | 6.6 | 2.11 | 7.3 |
b. Linearity/assay Reportable Range:
IMMULITE 2000 TSI Linearity was evaluated according to CLSI EP6-A. TSI positive and TSI negative samples were obtained from several commercial vendors. Sample sets were prepared gravimetrically pooling low and high samples.
Conclusion
Linearity data for % Difference was shown to be ± 15% or 0.50 IU/L (whichever is greater) for most samples; tested within range 0.50 - 40.0 IU/L with calibrators and pooled samples. Because of the heterogeneity of TSHR autoantibodies, certain patient samples may exhibit a non-linear dilution.
c. Traceability, Stability, Expected Values (controls, calibrators, methods):
Traceability:
The IMMULITE® 2000 TSI assay is traceable to NIBSC standard 08/204 and is manufactured using qualified materials and measurement procedures.
The instrument-stored assay calibration curve is based on a series of calibrators covering the claimed assay range and is specific for each lot of the assay.
Assay and component stability:
Real time shelf life stability testing to support the following claims for the unopened devices and opened components:
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Acceptance criteria for all components of the assay was assessed based on analyte drift as described in CLSI document EP25-A. The dose value of the component should be within the limits described in the table below except if below the LoQ of 0.10 IU/L where recovery cannot be properly determined. At each time point, all Control results must be within Quality Control established range, to validate the run.
| Component on Stability | Parameter | Drift Specifications |
|---|---|---|
| Reagents and Beads | Control 1 at ≤ -60°C | ≤ 15% from Day 0 mean |
| Reagents and Beads | Control 2 at ≤ -60°C | ≤ 10% from Day 0 mean |
| Reagents and Beads | CVM 1 at ≤ -60°C | ≤ 0.15 IU/L from Day 0 mean |
| Reagents and Beads | MDP 1 | ≤ 20% from Day 0 mean |
| Reagents and Beads | MDP 4 | ≤ 10% from Day 0 mean |
| Reagents and Beads | Cal J | ≤ 10% from Day 0 mean |
Closed vial testing (kit stored at 2 - 8 °C) was conducted at 0, 60, 120, 180, 270, 360, 450, and 540 days. Four replicates for the Low and High Adjustors and four replicates of each Control, MDP, and Calibrator J were run on each day of the study. Dose values of the Controls and samples were calculated from the Day 0 adjustment and from the adjustment performed on each subsequent day of testing.
Open vial/kit testing of components stored at 2 - 8°C was conducted at Days 0, 7, 8, 14, 30, 45, 60, 90, and 97. Open vial testing of aliquotted components stored at -20°C was conducted on Days 0, 30, 60, 90, 120, 150, 180, and 194. Four replicates of each Adjustor and four replicates of each Control were run on each day of the study.
| Component | Storage | Stability Claim |
|---|---|---|
| Kit, unopened | 2 – 8 °C | 12 Months |
| Bead Pack, open | 2 – 8 °C | 90 Days |
| Reagent wedge, open and on-board | 2 – 8 °C | 90 Days |
| Sample diluent, open (L2M2Z, L2M2Z4) | 2 – 8 °C | 30 Days |
| Sample diluent, open frozen aliquoted (L2M2Z, L2M2Z4) | -20 °C | 6 Months |
| Adjustors open (L2SIL, L2SIH) | 2 – 8 °C | 90 Days |
| Adjustors (L2SIL, L2SIH) frozen aliquotted | -20 °C | 4 Months |
| Controls open (L2SIC1, L2SIC2) | 2 – 8 °C | 90 Days |
| Controls (L2SIC1, L2SIC2) frozen aliquotted | -20 °C | 6 Months |
| CVM, unopened | 2 – 8 °C | 12 Months |
| CVM, opened and reconstituted | 2 – 8 °C | 30 Days |
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Sample stability:
The sample stability study supports the claim of stability for 24 hours at 20 - 25°C, 7 days at 2 - 8°C, and 12 months at -20°C for serum and plasma.
Adjustment interval (calibration curve) stability:
Real time testing supported the recommended adjustment interval of four weeks.
- d. Detection Limit:
Limit of Blank (LoB): Five TSI negative samples were analyzed on three IMMULITE® 2000 instruments over 3 days. The samples were tested using three lots of reagent for 2 runs with 2 replicates per run. The LoB result was determined by applying a nonparametric principle based on ranked ordered value using the following equation where p= (100-a) = 95 and NB = number of blank measurements = 180:
LoB rank position = [NB(p/100)+0.5]
The LoB was the 171.5th ranked result. The LoB was analyzed for each of the 3 lots. The highest LoB by lot was determined to be 0.03 IU/L.
Limit of Detection (LoD): Five TSI serum samples (mean concentrations ranging from 0.016 to 0.110 IU/L) were assayed in replicates of 4 using 3 reagent kit lots run for 3 days on 3 systems. Thirty-six observations were obtained for each sample. The LoD was determined by the following equation:
$$\mathbf{LoD} = \mathbf{LoB} + \mathbf{c}_p \mathbf{SD_L}$$
The LoD was analyzed for each of the 3 lots. The highest LoD by lot was determined to be 0.06 IU/L.
- e. Analytical Specificity:
Endogenous interferents:
Three serum pools with concentrations across the assay range were prepared and spiked separately with endogenous interferents. A control sample was prepared for each interfering substance by spiking the appropriate diluent at the same volume as the interfering substance; each sample was tested in triplicate. The interferents tested were: Intralipid (500 and 1000 mg/dL); Hemoglobin (200 and 500 mg/dL); Bilirubin: Conjugated and Unconjugated (20 and 40 mg/dL each); and K2-EDTA (9mg/mL). Heterophile samples, HAMA and Rheumatoid Factor, were also evaluated.
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No interference (≤ 10% different than control sample) was found when the means of control samples were compared to the means of the spiked samples, except in the case of hemoglobin. The sponsor has included limitations to this effect in the package insert: "Presence of hemoglobin at a concentration of 200mg/dL or higher may affect recovery."
Samples spiked with a five-fold excess of K2-EDTA anticoagulant were compared to normal serum to investigate the effect of a short blood draw on TSI assay results. Three samples were tested; all but one showed recovery within ± 10% of the serum control value. The sponsor has included limitations to this effect in the package insert: "Short Draw K2-EDTA Plasma samples may result in under-recovery of IMMULITE 2000 TSI results."
HAMA Study:
TSI samples were prepared at three target concentrations across the assay range. Samples were divided into control groups (spiked with HAMA negative serum) and test groups (spiked with HAMA positive serum to final HAMA concentration of 10 ng/mL or 40 ng/mL). Mean values for each sample were determined on IMMULITE 2000 (n=12) and the percent (%) difference from the control samples was calculated.
The assay demonstrated individual sample bias of <4% when evaluated at the 10 ng/mL and 40 ng/mL of HAMA.
Rheumatoid Factor (RF) Study:
TSI samples were prepared at three target concentrations across the assay range. Samples were divided into control groups (spiked with RF negative serum) and test groups (spiked with RF positive serum to final RF concentration of 100 IU/mL or 200 IU/mL). Mean values for each sample were determined on IMMULITE 2000 (n=12) and the percent (%) difference from the control samples was calculated.
The assay demonstrated individual sample bias of <5% when evaluated at the 100 IU/mL and 200 IU/mL of RF.
Cross Reactivity:
Six (6) potential biological interferent samples (TSH, FSH, LH, hCG, aTPO, and aTG) were prepared by spiking known concentrations into three TSI serum pools spanning the analytical measuring range of the assay.
The assay demonstrated cross-reactivity bias of ≤10% for all interferents and all samples.
- f. Assay cut-off:
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The cut-off of the IMMULITE® 2000 TSI assay was determined with positive and negative patient samples by a ROC analysis, with a balanced consideration of sensitivity and specificity. A total of 434 samples were used, consisting of 164 Graves' disease patient samples and 270 samples with other thyroid or autoimmune diseases. A result ≥ 0.55 IU/L indicates hyperthyroid Graves' disease. A result of < 0.55 IU/L indicates the patient does not have Graves' disease or is in remission.
-
- Comparison Studies
- Method Comparison with predicate device: a.
The Thyretain TSI Reporter BioAssay, a qualitative assay for the detection of stimulating thyroid hormone receptor (TSHR) autoantibodies, was identified as the predicate device.
A method comparison was performed to compare the performance of the IMMULITE 2000 TSI assay to the Thyretain™ TSI Reporter BioAssay using 811 serum samples from patients with Graves' disease, other thyroid or autoantibody diseases. Specimens were tested using the IMMULITE 2000 TSI assay at two external sites and one internal site. Specimens were tested using the Thyretain device at one of the external sites
| IMMULITE2000 TSI | THYRETAIN TSI ReporterBioAssay | |
|---|---|---|
| Negative | Positive | |
| Negative | 422 | 14 |
| Positive | 59 | 316 |
| Total | 481 | 330 |
Positive Agreement: 95.8% (95% CI: 93.0 – 97.7) Negative Agreement: 87.7% (95% CI: 84.5 - 90.5) Overall Agreement: 91.0% (95% CI: 88.8 - 92.9)
b. Matrix Comparison:
Graves' Disease sets of matched serum and plasma samples were collected in the following anti-coagulant tubes: serum clot tube, lithium heparin plasma tube, serum separator tube (SST), and K2-EDTA plasma tube. Sample concentrations spanned the analytical measuring range of the assay. Data was analyzed using Passing & Bablock regression plots. Results were as follows:
| Serum vs. | Slope | Intercept | Correlation Coefficient |
|---|---|---|---|
| SST Serum | 1.01 | 0.00 | 0.99 |
| K2-EDTAPlasma | 1.03 | -0.01 | 0.99 |
| Lithium | 0.99 | -0.01 | 0.99 |
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| Heparin Plasma | ||
|---|---|---|
| ---------------- | -- | -- |
-
- Clinical Studies:
- a. Clinical Sensitivity and Specificity
Clinical Sensitivity and Specificity: Serum samples from 361 treated and untreated hyperthyroid Graves' disease patients, and 404 individuals with other thyroid or autoimmune diseases were evaluated. The TSI values for the negative patients with other thyroid or autoimmune diseases had an upper limit of 0.39 IU/L. At the 0.55 IU/L cut-off, the clinical sensitivity and specificity were 98.6% and 98.5% respectively (see Clinical Sensitivity and Specificity table).
In this clinical study, 3.6% (4/11) of the Hashimoto's thyroiditis (HT) patients were TSI positive. Two of the four HT patient samples were also positive in other commercially available TSI or Anti-TSHR assays. The third HT patient was biochemically hyperthyroid at the time of HT diagnosis. The simultaneous occurrence of HT and Graves' disease, although rare, has been reported in the literature. The fourth HT patient had a TSI result of 0.69 IU/L, slightly above the assay cut-off. Other clinical studies have detected TSI in 7% of HT patients without thyroid-associated orbitopathy (TAO) and in over 68% of the HT patients with TAO.
| Other Thyroid andAutoimmune DiseaseSamples | n |
|---|---|
| Multinodular goiter | 26 |
| Hashimoto's thyroiditis | 111 |
| Thyroid Cancer | 37 |
| Systemic LupusErythematosus | 25 |
| Rheumatoid Arthritis | 25 |
| Ulcerative Colitis | 25 |
| Diabetes (Type 1 & 2) | 20 |
| Celiac Disease | 30 |
| Crohn's Disease | 25 |
| Toxic multinodular goiter | 6 |
| Sub-acute thyroiditis | 6 |
Sample Distribution of Other Diseases
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| Addison's Disease | 13 |
|---|---|
| Sjögren's Syndrome | 22 |
| Other diseases | 33 |
| TOTAL | 404 |
Clinical Sensitivity and Specificity
| Graves' Disease Diagnosis | ||
|---|---|---|
| IMMULITE2000 TSI | Negative | Positive |
| Negative | 398 | 5 |
| Positive | 6 | 356 |
| Total | 404 | 361 |
Clinical Sensitivity: 98.6% (95% CI: 96.8 – 99.5) Clinical Specificity: 98.5% (95% CI: 96.8 – 99.5)
- Other clinical supportive data: b. Not applicable.
- Clinical cut-off: 4. Not applicable.
-
- Expected values/Reference range:
A total of 842 serum samples from apparently healthy males (n = 151), non-pregnant females (n = 155), first trimester (n = 169), second trimester (n = 191), and third trimester (n = 176) pregnant donors were analyzed using the IMMULITE 2000 TSI assay. The results from this study suggest a nonparametric 97.5th percentile of < 0.10 IU/L.
N. Proposed Labeling:
The labeling is sufficient and it satisfies the requirements of 21 CFR Part 809.10.
O. Conclusion:
The submitted information in this premarket notification is complete and supports a substantial equivalence decision.
§ 866.5870 Thyroid autoantibody immunological test system.
(a)
Identification. A thyroid autoantibody immunological test system is a device that consists of the reagents used to measure by immunochemical techniques the thyroid autoantibodies (antibodies produced against the body's own tissues). Measurement of thyroid autoantibodies may aid in the diagnosis of certain thyroid disorders, such as Hashimoto's disease (chronic lymphocytic thyroiditis), nontoxic goiter (enlargement of thyroid gland), Grave's disease (enlargement of the thyroid gland with protrusion of the eyeballs), and cancer of the thyroid.(b)
Classification. Class II (performance standards).