(267 days)
The i-STAT CG8+ cartridge with the i-STAT 1 System is intended for use in the in vitro quantification of H, partial pressure of oxygen (PO2), and partial pressure of carbon dioxide (PCO2) in arterial, venous, or capillary whole blood in point of care or clinical laboratory settings.
pH, PO2, and PCO2 measurements are used in the diagnosis, monitoring, and treatment of respiratory, metabolic and acid-base disturbances.
The i-STAT CG8+ cartridge is used with the i-STAT 1 analyzer as part of the i-STAT 1 System and contains test reagents to measure pH, partial pressure of oxygen (PO2), and partial pressure of carbon dioxide (PCO2) in arterial, venous or capillary whole blood.
The i-STAT 1 System is an in vitro diagnostic (IVD) medical device intended for the quantitative determination of various clinical chemistry tests contained within i-STAT cartridges using whole blood. The i-STAT 1 System consists of a portable blood analyzer (i-STAT 1 analyzer), single-use disposable test cartridges (i-STAT cartridges), liquid quality control and calibration verification materials, and accessories (i-STAT 1 Downloader/Recharger, i-STAT Electronic Simulator and i-STAT 1 Printer). The i-STAT 1 System, including the i-STAT CG8+ cartridge, is designed for use by trained medical professionals in point of care or clinical laboratory settings and is for prescription use only.
The i-STAT CG8+ cartridge contains the required sensors, a fluid pack (calibrant pouch), a sample entry well and closure, fluid channels, waste chamber, and the necessary mechanical features for controlled fluid movement within cartridge. The i-STAT cartridge format allows all the tests in the cartridge to be performed simultaneously. All the test steps and fluid movement occur within the i-STAT CG8+ cartridges require two to three drops of whole blood applied to the cartridge using a transfer device by the trained user before the cartridge is placed within the analyzer.
The i-STAT 1 analyzer is a handheld, in vitro diagnostic analytical device designed to run only i-STAT test cartridges. The instrument interacts with the i-STAT CG8+ cartridge to move fluid across the sensors and generate a quantitative result (within approximately 2 minutes).
The provided text describes the analytical performance and comparison studies for the Abbott i-STAT CG8+ cartridge with the i-STAT 1 System, specifically for pH, PO2, and PCO2 measurements. It does not contain information about the establishment of ground truth by expert readers, multi-reader multi-case (MRMC) studies, or the training set for an AI/ML device. This document is a 510(k) summary for an in vitro diagnostic device, not an AI/ML-driven device.
Therefore, the following information cannot be extracted from the given text:
- Number of experts used to establish the ground truth.
- Qualifications of those experts.
- Adjudication method for the test set.
- Multi-reader multi-case (MRMC) comparative effectiveness study, effect size of human readers improving with AI vs without AI assistance.
- Standalone (algorithm only without human-in-the-loop performance) study.
- Type of ground truth (expert consensus, pathology, outcomes data, etc.) as the ground truth is established by a comparative method (predicate device or standard laboratory methods) for analytical performance.
- Sample size for the training set.
- How ground truth for the training set was established.
However, I can extract information related to acceptance criteria (implied by the study results meeting certain performance metrics) and the study that proves the device meets those criteria for the i-STAT CG8+ cartridge.
Here's a breakdown of the available information:
1. Table of Acceptance Criteria and Reported Device Performance
The document doesn't explicitly state "acceptance criteria" in a separate table for each test, but rather presents performance data (precision, linearity, detection limits, interference, method comparison) which are implicitly compared against pre-defined acceptance criteria (not explicitly listed but implied by the "met acceptance criteria" statements in the Altitude study and the overall conclusion of substantial equivalence).
Based on the provided data, here's a representation for the key performance metrics.
The acceptance criteria are implicitly met if the reported performance supports substantial equivalence.
| Performance Characteristic | Acceptance Criteria (Implied / Qualitative) | Reported Device Performance (i-STAT CG8+) |
|---|---|---|
| Precision (Aqueous) | Demonstrate consistent reproducibility over time and across runs/days. | 20-Day Precision (Table 2):- pH: Within-Laboratory SD up to 0.00482 pH units (0.07% CV).- PO2: Within-Laboratory SD up to 10.80 mmHg (2.91% CV).- PCO2: Within-Laboratory SD up to 1.307 mmHg (1.48% CV).Multi-Site/Operator (Table 3):- pH: Overall SD up to 0.00579 pH units (0.09% CV).- PO2: Overall SD up to 12.24 mmHg (4.07% CV).- PCO2: Overall SD up to 1.489 mmHg (3.63% CV). |
| Precision (Whole Blood) | Demonstrate consistent reproducibility across different blood sample types (venous, arterial, capillary). | Whole Blood Precision (Table 4):- pH: %CV from 0.04% to 0.08% for venous/arterial, up to 0.34% for capillary.- PO2: %CV from 0.97% to 4.18% for venous/arterial/capillary (excluding N/A ranges). Capillary PO2 up to 10.65% CV.- PCO2: %CV from 0.65% to 2.85% for venous/arterial, up to 6.56% for capillary. |
| Linearity | Demonstrate linearity over the specified reportable range. | Regression Summary (Table 5):- pH: Slope 1.011, Intercept -0.098, R² 0.9994 (Range Tested: 6.4290 – 7.8522 pH units).- PO2: Slope 0.977, Intercept 1.062, R² 0.9956 (Range Tested: 4.4 – 700.0 mmHg).- PCO2: Slope 1.029, Intercept -1.144, R² 0.9991 (Range Tested: 2.40 – 148.38 mmHg). "demonstrated linearity over the reportable range for each i-STAT test." |
| Limit of Quantitation (LoQ) | LoQ to be at or below the lower limit of the reportable range. | Summary of LoQ Results (Table 6):- pH: Lower limit 6.500, Determined LoQ 6.464.- PO2: Lower limit 5, Determined LoQ 5.- PCO2: Lower limit 5.0, Determined LoQ 3.2. |
| Analytical Specificity (Interference) | No significant interference from specified substances at toxic/pathological concentrations. | Potentially Interfering Substances (Table 7):No interference identified for pH, PO2, and PCO2 from Acetaminophen, Atracurium, Bilirubin, Calcium, Ethanol, Hemoglobin, Ibuprofen, Intralipid 20%, Morphine, Potassium, Sodium, Thiopental, Triglyceride at specified concentrations. |
| Altitude Performance | Equivalent performance between candidate and comparator conditions at approximately 10,000 feet above sea level. | Summary of Altitude Study Results (Table 8):- pH: r=1.00, Slope=0.99 (95% CI 0.984 to 0.998).- PO2: r=1.00, Slope=1.02 (95% CI 1.000 to 1.037).- PCO2: r=1.00, Slope=0.98 (95% CI 0.969 to 0.989)."met acceptance criteria and demonstrated equivalent performance". |
| Method Comparison (vs. Predicate) | High correlation (r) and acceptable bias at medical decision levels when compared to the predicate device. | Pooled Data (Table 9):- pH: N=468, r=0.99, Slope=1.00, Intercept=0.00. Bias at MDLs: -0.0040.- PO2: N=461, r=0.99, Slope=1.03, Intercept=-0.72. Bias at MDLs: 0.1 to 0.9.- PCO2: N=465, r=0.97, Slope=1.08, Intercept=-1.13. Bias at MDLs: 1.79 to 4.71.Capillary Only (Table 10 & 11):- pH: N=195, r=0.98, Slope=1.02, Intercept=-0.11. Bias at MDLs: -0.0160 to -0.0041 (native N=179).- PO2: N=190, r=0.99, Slope=1.02, Intercept=-1.75. Bias at MDLs: -1.8 to -0.7 (native N=175).- PCO2: N=189, r=0.97, Slope=1.09, Intercept=-1.90. Bias at MDLs: 1.17 to 3.36 (native N=179). |
| Matrix Equivalence | Demonstrate acceptable equivalence between anticoagulated and non-anticoagulated specimens. | Matrix Equivalence (Table 12):- pH: N=241, r=0.98, Slope=0.97, Intercept=0.19.- PO2: N=241, r=0.98, Slope=0.94, Intercept=1.28.- PCO2: N=241, r=0.96, Slope=1.02, Intercept=-0.23. |
2. Sample sizes used for the test set and the data provenance
- Precision Studies (Aqueous):
- 20-day precision: N=80 for each fluid level (5 levels per analyte). Provenance not explicitly stated, but typically conducted in-house by the manufacturer.
- Multi-site/Operator precision: N=90 or N=96 for each fluid level (5 levels per analyte). Conducted at three (3) sites. Provenance not explicitly stated (e.g., country of origin), assumed to be domestic (US) unless otherwise specified.
- Precision Study (Whole Blood): Sample sizes vary by analyte and sample type/range, ranging from N=0 (N/A) to N=108. Collected across multiple point-of-care sites. Provenance not explicitly stated. These are retrospective or newly collected clinical samples used for analytical testing.
- Linearity Study: "whole blood samples of varying analyte levels for each i-STAT test." Specific N not provided for linearity, but likely a smaller set sufficient to cover the range.
- Detection Limit (LoQ) Study: "two (2) i-STAT CG8+ cartridge lots and whole blood that was altered to a low analyte level". Specific N not provided, but typically involves repeat measurements.
- Interference Study: "whole blood samples." Specific N not provided for interference testing.
- Altitude Study: "whole blood samples at relevant analyte levels across the reportable range for each test." Specific N not provided for altitude study.
- Method Comparison Study:
- Pooled (Arterial/Venous/Capillary): N=468 (pH), 461 (PO2), 465 (PCO2). Specimens collected across multiple point-of-care sites.
- Capillary only: N=195 (pH), 190 (PO2), 189 (PCO2). This set includes native and contrived samples.
- Native Capillary only bias: N=179 (pH), 175 (PO2), 179 (PCO2). Specimens collected from skin puncture.
- Data provenance: "collected across multiple point of care sites," implying prospective collection of patient samples for these comparison studies. Country of origin not specified, but usually US for FDA submissions. The studies reference CLSI guidance documents.
- Matrix Equivalence Study: N=241. "non-anticoagulated venous and arterial whole blood specimens."
All studies appear to be prospective data collection or laboratory studies designed for validation, based on the testing methodologies described (e.g., CLSI guidelines, collection of new samples).
3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts
Not applicable. This is an in vitro diagnostic device measuring objective physiological parameters (pH, PO2, PCO2). The "ground truth" or comparative value for these measurements is established by a "comparative method" (RAPIDPoint 500/500e, which is another blood gas analyzer) or by standard reference methods/materials (e.g., NIST SRMs, tonometered aqueous standards). There is no human interpretation or expert consensus involved in determining the "truth" for these quantitative chemical measurements.
4. Adjudication method (e.g. 2+1, 3+1, none) for the test set
Not applicable, as ground truth is not established by human readers requiring adjudication.
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
Not applicable. This device is not an AI/ML device that assists human readers. It is an IVD for direct measurement of blood gas parameters.
6. If a standalone (i.e. algorithm only without human-in-the-loop performance) was done
Not applicable. This device is a measurement system; its performance is inherently "standalone" in that it produces a quantitative result without human-in-the-loop interpretation of images or complex data patterns. It outputs a direct measurement.
7. The type of ground truth used (expert consensus, pathology, outcomes data, etc)
The "ground truth" for the device's measurements (pH, PO2, PCO2) is established by:
- Reference materials/standards: NIST SRMs and certified specialty medical gas tanks for traceability and calibration (Section VI, Traceability).
- Comparative method: The predicate device, the Siemens RAPIDPoint 500e Blood Gas System, or the RAPIDPoint 500/500e in general, for method comparison studies (Section VII.B.a). This is considered a highly accurate and established method for these analytes.
- Internal reference: For "other sensitivity studies" like Altitude, the i-STAT CG4+ (blue) cartridges on the i-STAT 1 analyzer served as a comparator device.
8. The sample size for the training set
Not applicable. This is not an AI/ML device that requires a "training set" in the machine learning sense. The device is based on established electrochemical principles, and its performance is validated through analytical studies.
9. How the ground truth for the training set was established
Not applicable, as there is no "training set." The device is calibrated using reagents contained within the cartridge, traceable to known standards (NIST SRMs).
{0}------------------------------------------------
Image /page/0/Picture/0 description: The image contains the logo of the U.S. Food and Drug Administration (FDA). On the left is the Department of Health & Human Services logo. To the right of that is the FDA logo, which is a blue square with the letters "FDA" in white. To the right of the blue square is the text "U.S. FOOD & DRUG ADMINISTRATION" in blue.
October 27, 2023
Abbott Point of Care Inc. Jacquelyn Gesumaria Principal Regulatory Affairs Specialist 400 College Road East Princeton, New Jersey 08540
Re: K230285
Trade/Device Name: i-STAT CG8+ cartridge with the i-STAT 1 System Regulation Number: 21 CFR 862.1120 Regulation Name: Blood Gases (PCO2, PO2) And Blood pH Test System Regulatory Class: Class II Product Code: CHL Dated: September 28, 2023 Received: September 28, 2023
Dear Jacquelyn Gesumaria:
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 (the 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 available 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.
Additional information about changes that may require a new premarket notification are provided in the FDA guidance documents entitled "Deciding When to Submit a 510(k) for a Change to an Existing Device" (https://www.fda.gov/media/99812/download) and "Deciding When to Submit a 510(k) for a Software Change to an Existing Device" (https://www.fda.gov/media/99785/download).
{1}------------------------------------------------
Your device is also subject to, among other requirements, the Quality System (QS) regulation (21 CFR Part 820), which includes, but is not limited to, 21 CFR 820.30, Design controls; 21 CFR 820.90, Nonconforming product; and 21 CFR 820.100, Corrective and preventive action. Please note that regardless of whether a change requires premarket review, the QS regulation requires device manufacturers to review and approve changes to device design and production (21 CFR 820.30 and 21 CFR 820.70) and document changes and approvals in the device master record (21 CFR 820.181).
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 Part 801 and Part 809); medical device reporting of medical device-related adverse events) (21 CFR Part 803) for devices or postmarketing safety reporting (21 CFR Part 4, Subpart B) for combination products (see https://www.fda.gov/combination-products/guidance-regulatory-information/postmarketing-safetyreporting-combination-products); good manufacturing practice requirements as set forth in the quality systems (QS) regulation (21 CFR Part 820) for devices or current good manufacturing practices (21 CFR Part 4, Subpart A) for combination products; and, if applicable, the electronic product radiation control provisions (Sections 531-542 of the Act); 21 CFR Parts 1000-1050.
Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21 CFR 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,
Paula V. Caposino -S
Paula Caposino, Ph.D. Acting Deputy Director Division of Chemistry and Toxicology Devices OHT7: Office of In Vitro Diagnostics Office of Product Evaluation and Quality Center for Devices and Radiological Health
Enclosure
{2}------------------------------------------------
Indications for Use
510(k) Number (if known) K230285
Device Name i-STAT CG8+ cartridge with the i-STAT 1 System
Indications for Use (Describe)
The i-STAT CG8+ cartridge with the i-STAT 1 System is intended for use in the in vitro quantification of H, partial pressure of oxygen (PO2), and partial pressure of carbon dioxide (PCO2) in arterial, venous, or capillary whole blood in point of care or clinical laboratory settings.
pH, PO2, and PCO2 measurements are used in the diagnosis, monitoring, and treatment of respiratory, metabolic and acid-base disturbances.
| 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) |
CONTINUE ON A SEPARATE PAGE IF NEEDED.
This section applies only to requirements of the Paperwork Reduction Act of 1995.
DO NOT SEND YOUR COMPLETED FORM TO THE PRA STAFF EMAIL ADDRESS BELOW.
The burden time for this collection of information is estimated to average 79 hours per response, including the time to review instructions, search existing data sources, gather and maintain the data needed and complete and review the collection of information. Send comments regarding this burden estimate or any other aspect of this information collection, including suggestions for reducing this burden, to:
Department of Health and Human Services Food and Drug Administration Office of Chief Information Officer Paperwork Reduction Act (PRA) Staff PRAStaff(@fda.hhs.gov
"An agency may not conduct or sponsor, and a person is not required to respond to, a collection of information unless it displays a currently valid OMB number."
{3}------------------------------------------------
Image /page/3/Picture/0 description: The image shows the Abbott logo. The logo consists of a blue, stylized letter "A" on the left and the word "Abbott" in black, bold font on the right. The blue "A" is made up of three horizontal lines that are connected on the left side.
510(k) SUMMARY
The information in this 510(k) summary is being submitted in accordance with the requirements of 21 CFR 807.92.
I. SUBMITTER INFORMATION
| Owner | Abbott Point of Care Inc.400 College Road EastPrinceton, NJ 08540 |
|---|---|
| Contact | Primary: Jacquelyn GesumariaPrincipal Regulatory Affairs SpecialistPhone: 609-454-9384 |
| Secondary: Mojgan SoleimaniAssociate Director Regulatory AffairsPhone: 613-295-0932 | |
| Date Prepared | October 27, 2023 |
II. DEVICE INFORMATION
| Proprietary Name | i-STAT CG8+ cartridge with the i-STAT 1 System |
|---|---|
| Common Name | Blood gas test, analyzer, handheld |
| 510(k) Number | K230285 |
| Product Code | Device ClassificationName | RegulationNumber | Class | Panel |
|---|---|---|---|---|
| CHL | Electrode, IonSpecific, pH | 862.1120 | II | Clinical Chemistry |
| CHL | Electrode, IonSpecific, PCO2 | 862.1120 | II | Clinical Chemistry |
| CHL | Electrode, IonSpecific PO2 | 862.1120 | II | Clinical Chemistry |
{4}------------------------------------------------
III. PREDICATE DEVICE
RAPIDPoint 500e Blood Gas System Proprietary Name
510(k) Number K192240
| ProductCode | Device ClassificationName | RegulationNumber | Class | Panel |
|---|---|---|---|---|
| CHL | Electrode, Ion Specific, pH | 862.1120 | II | Clinical Chemistry |
| CHL | Electrode, Ion Specific,PCO2 | 862.1120 | II | Clinical Chemistry |
| CHL | Electrode, Ion Specific PO2 | 862.1120 | II | Clinical Chemistry |
IV. DEVICE DESCRIPTION
The i-STAT CG8+ cartridge is used with the i-STAT 1 analyzer as part of the i-STAT 1 System and contains test reagents to measure pH, partial pressure of oxygen (PO2), and partial pressure of carbon dioxide (PCO2) in arterial, venous or capillary whole blood.
The i-STAT 1 System is an in vitro diagnostic (IVD) medical device intended for the quantitative determination of various clinical chemistry tests contained within i-STAT cartridges using whole blood. The i-STAT 1 System consists of a portable blood analyzer (i-STAT 1 analyzer), single-use disposable test cartridges (i-STAT cartridges), liquid quality control and calibration verification materials, and accessories (i-STAT 1 Downloader/Recharger, i-STAT Electronic Simulator and i-STAT 1 Printer). The i-STAT 1 System, including the i-STAT CG8+ cartridge, is designed for use by trained medical professionals in point of care or clinical laboratory settings and is for prescription use only.
The i-STAT CG8+ cartridge contains the required sensors, a fluid pack (calibrant pouch), a sample entry well and closure, fluid channels, waste chamber, and the necessary mechanical features for controlled fluid movement within cartridge. The i-STAT cartridge format allows all the tests in the cartridge to be performed simultaneously. All the test steps and fluid movement occur within the i-STAT CG8+ cartridges require two to three drops of whole blood applied to the cartridge using a transfer device by the trained user before the cartridge is placed within the analyzer.
The i-STAT 1 analyzer is a handheld, in vitro diagnostic analytical device designed to run only i-STAT test cartridges. The instrument interacts with the i-STAT CG8+ cartridge to move fluid across the sensors and generate a quantitative result (within approximately 2 minutes).
V. INTENDED USE STATEMENT
The i-STAT CG8+ cartridge with the i-STAT 1 System is intended for use in the in vitro quantification of pH, partial pressure of oxygen (PO2), and partial pressure of carbon dioxide (PCO2) in arterial, venous, or capillary whole blood in point of care or clinical laboratory settings.
pH, PO2, and PCO2 measurements are used in the diagnosis, monitoring, and treatment of respiratory, metabolic and acid-base disturbances.
{5}------------------------------------------------
VI. SUMMARY COMPARISON OF TECHNOLOGICAL CHARACTERISTICS
| Table 1: Similarities and Differences (Test and Instrument): pH, PO2, and PCO2 in Arterial, Venous, and Capillary Whole Blood | ||
|---|---|---|
| Feature or Characteristic | Candidate Device:pH, PO2 and PCO2 Tests in the:i-STAT CG8+ cartridgewith the i-STAT 1 System | Predicate Device:pH, PO2 and PCO2 Tests in theSiemens RAPIDPoint 500eBlood Gas System(K192240) |
| Intended Use | The i-STAT CG8+ cartridge with thei-STAT 1 System is intended for use inthe in vitro quantification of sodium,potassium, ionized calcium, glucose,hematocrit, pH, partial pressure ofoxygen (PO2), and partial pressure ofcarbon dioxide (PCO2) in arterial,venous, or capillary whole blood inpoint of care or clinical laboratorysettings.pH, PO2, and PCO2 measurements areused in the diagnosis, monitoring, andtreatment of respiratory, metabolic andacid-base disturbances. | The RAPIDPoint 500e Blood Gas System isintended for in vitro diagnostic use and isdesigned to provide the determination inwhole blood for the following parameters:• Partial pressure of carbon dioxide• Partial pressure of oxygen• pH• Sodium• Potassium• Ionized Calcium• Chloride• Glucose• Lactate• Total Hemoglobin and fractions: FO2Hb,FCOHb, FMetHb, FHHb• Neonatal BilirubinThe RAPIDPoint 500e Blood Gas System isalso intended for in vitro testing of pleuralfluid samples for the pH parameter. The pHmeasurement of pleural fluid can be aclinically useful tool in the management ofpatients with parapneumonic effusions. Thefollowing critical value applies to pleuralfluid pH: pH > 7.3 is measured inuncomplicated parapneumonic effusions. Allpleural fluids with a pH measurement < 7.3are referred to as complicatedparapneumonic effusions and are exudativein nature. This test system is intended foruse in point of care or laboratory settings.pCO2, pO2, pH: Measurements of bloodgases (pCO2, pO2) and blood pH are used inthe diagnosis and treatment of life-threatening acid-base disturbances. |
| DeviceClassification | Same | Class II |
| Product Code | Same | CHL |
| Table 1: Similarities and Differences (Test and Instrument): pH, PO2, and PCO2 in Arterial, Venous, and Capillary Whole Blood | ||
| Feature orCharacteristic | Candidate Device:pH, PO2 and PCO2 Tests in the:i-STAT CG8+ cartridgewith the i-STAT 1 System | Predicate Device:pH, PO2 and PCO2 Tests in theSiemens RAPIDPoint 500eBlood Gas System(K192240) |
| RegulationNo. | Same | 862.1120 |
| ReportableRange | pHSame | pH6.500 – 7.800 |
| PO2$5-700 mmHg$$0.7-93.3 kPa$ | pO2$10.0-700.0 mmHg$$1.33-93.32 kPa$ | |
| PCO2$5-130 mmHg$$0.67-17.33 kPa$ | PCO2$5.0-200.0 mmHg$$0.66-26.66 kPa$ | |
| Sample Type | Arterial, venous or capillary whole blood | Whole blood (Arterial, Venous and Capillary for all analytes)Pleural Fluid (for pH test only) |
| SampleVolume | 95 μL | 100 μL |
| SamplePreparation | Same | Ready to use |
| Samplecollection | Without anticoagulant (for arterial and venous whole blood sample types)With balanced heparin anticoagulant or lithium heparin anticoagulant (for arterial, venous, and capillary whole blood sample types) | With balanced heparin anticoagulant or lithium heparin anticoagulant |
| Traceability | pHTraceable to NIST SRMs186-I, 186-II, 185 and 187 | pHTraceable to NIST SRM 186 reference materials via the IFCC blood reference method. |
| PO2, PCO2Traceable to NIST SRMs via commercially available certified specialty medical gas tanks | PO2, PCO2Traceable to tonometered aqueous standards prepared using NIST traceable temperature and pressure standards and gravimetrically prepared precision gas standards. | |
| Calibration | 1-point calibration using reagents contained within cartridge | 1-point, 2-point and full calibration using automated on board reagent |
| Table 1: Similarities and Differences (Test and Instrument): pH, PO2, and PCO2 in Arterial, Venous,and Capillary Whole Blood | ||
| Feature orCharacteristic | Candidate Device:pH, PO2 and PCO2 Tests in the:i-STAT CG8+ cartridgewith the i-STAT 1 System | Predicate Device:pH, PO2 and PCO2 Tests in theSiemens RAPIDPoint 500eBlood Gas System(K192240) |
| Principle ofMeasurement | pH, PCO2: Potentiometric measurementbetween active working sensor andindependent reference sensorPO2: Amperometric measurement ofoxygen reduction current | pH, PCO2: Potentiometric methodPO2: Amperometric measurement |
| ReagentFormat | Same | Cartridge |
| StorageConditions | Refrigerated at 2-8°C (35-46°F) untilexpiration dateRoom Temperature at 18-30°C (64-86°F)for 2 months | Refrigerated at 2 to 8°C (35 to 46°F) untilstated "install-by-date"; 28 additional daysafter installation on systemRoom Temperature for up to 1 day |
| Analyzer Type | Handheld | Benchtop |
{6}------------------------------------------------
{7}------------------------------------------------
PERFORMANCE CHARACTERISTICS VII.
A. Analytical Performance
a. Precision/Reproducibility:
i. Precision 20 days (Aqueous materials)
The precision of the i-STAT pH, Partial Pressure of Oxygen (PO2), and Partial Pressure of Carbon Dioxide (PCO2) tests in the i-STAT CG8+ cartridge on the i-STAT 1 System was evaluated using five (5) levels of aqueous material. This 20day precision testing was based on CLSI document EP05-A3: Evaluation of Precision of Quantitative Measurement Procedures; Approved Guideline – Third Edition. The study was conducted using multiple analyzers and one (1) test cartridge lot over 20 days at one site. Repeatability, between-run, between-day, and within-laboratory precision were estimated for each level. The results of the 20-day precision study for the i-STAT CG8+ cartridge on the i-STAT 1 System are shown in Table 2.
| Table 2: Results of 20-Day Precision of the i-STAT CG8+ Cartridge on the i-STAT 1 Analyzer | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Test | FluidLevel | N | Mean | Repeatability | Between-run | Between-day | Within-Laboratory | |||||
| (units) | SD | %CV | SD | %CV | SD | %CV | SD | %CV | ||||
| pH(pH units) | CV L1 | 80 | 6.5831 | 0.00284 | 0.04 | 0.00354 | 0.05 | 0.00162 | 0.02 | 0.00482 | 0.07 | |
| CV L2 | 80 | 7.0326 | 0.00165 | 0.02 | 0.00121 | 0.02 | 0.00102 | 0.01 | 0.00229 | 0.03 | ||
| CV L3 | 80 | 7.4574 | 0.00118 | 0.02 | 0.00170 | 0.02 | 0.00065 | 0.01 | 0.00217 | 0.03 | ||
| CV L4 | 80 | 7.6365 | 0.00133 | 0.02 | 0.00201 | 0.03 | 0.00072 | 0.01 | 0.00251 | 0.03 | ||
| CV L5 | 80 | 7.9612 | 0.00244 | 0.03 | 0.00188 | 0.02 | 0.00090 | 0.01 | 0.00321 | 0.04 | ||
| PO2(mmHg) | CV L1 | 80 | 75.7 | 1.93 | 2.54 | 1.45 | 1.92 | 0.77 | 1.02 | 2.53 | 3.35 | |
| CV L2 | 80 | 87.3 | 1.81 | 2.07 | 0.46 | 0.53 | 0.55 | 0.63 | 1.94 | 2.23 | ||
| CV L3 | 80 | 115.0 | 2.40 | 2.08 | 1.76 | 1.53 | 0.47 | 0.41 | 3.01 | 2.62 | ||
| CV L4 | 80 | 144.1 | 2.74 | 1.90 | 2.62 | 1.82 | 1.02 | 0.70 | 3.92 | 2.72 | ||
| CV L5 | 80 | 371.6 | 6.25 | 1.68 | 8.29 | 2.23 | 2.97 | 0.80 | 10.80 | 2.91 |
{8}------------------------------------------------
| Table 2: Results of 20-Day Precision of the i-STAT CG8+ Cartridge on the i-STAT 1 Analyzer | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Test(units) | FluidLevel | N | Mean | Repeatability | Between-run | Between-day | Within-Laboratory | |||||
| SD | %CV | SD | %CV | SD | %CV | SD | %CV | |||||
| PCO2(mmHg) | CV L1 | 80 | 88.55 | 0.781 | 0.88 | 0.973 | 1.10 | 0.392 | 0.44 | 1.307 | 1.48 | |
| CV L2 | 80 | 54.96 | 0.598 | 1.09 | 0.139 | 0.25 | 0.055 | 0.10 | 0.616 | 1.12 | ||
| CV L3 | 80 | 28.90 | 0.300 | 1.04 | 0.082 | 0.28 | 0.082 | 0.28 | 0.321 | 1.11 | ||
| CV L4 | 80 | 22.59 | 0.268 | 1.19 | 0.112 | 0.50 | 0.066 | 0.29 | 0.298 | 1.32 | ||
| CV L5 | 80 | 13.81 | 0.335 | 2.42 | 0.157 | 1.13 | 0.181 | 1.31 | 0.412 | 2.98 |
ii. Multi-site and operator-to-operator precision (Aqueous materials)
Multi-day precision testing was performed at three (3) sites using a panel of aqueous solutions containing five (5) levels of pH, PO2, and PCO2. At each site, each level was tested once a day by two (2) operators for five (5) days on six (6) i-STAT 1 analyzers using i-STAT CG8+ cartridges. Within-run, between-day, betweenoperator and within-site (total) variance components were calculated by site. These components were also calculated for all sites combined and provided in the Table 3 below.
{9}------------------------------------------------
| Table 3: Multi-Day Precision of the i-STAT CG8+ Cartridge on the i-STAT 1 Analyzer | |||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Test(units) | FluidLevel | N | Mean | Within-Run | Between-Day | Between-Operator | Within-Site (Total) | Between-Site | Overall | ||||||
| SD | %CV | SD | %CV | SD | %CV | SD | %CV | SD | %CV | SD | %CV | ||||
| pH(pH units) | CV L1 | 90 | 6.5829 | 0.00395 | 0.06 | 0.00267 | 0.04 | 0.00329 | 0.05 | 0.00579 | 0.09 | 0.00000 | 0.00 | 0.00579 | 0.09 |
| CV L2 | 90 | 7.0332 | 0.00317 | 0.05 | 0.00135 | 0.02 | 0.00054 | 0.01 | 0.00349 | 0.05 | 0.00000 | 0.00 | 0.00349 | 0.05 | |
| CV L3 | 96 | 7.4571 | 0.00231 | 0.03 | 0.00080 | 0.01 | 0.00085 | 0.01 | 0.00258 | 0.03 | 0.00000 | 0.00 | 0.00258 | 0.03 | |
| CV L4 | 90 | 7.6372 | 0.00184 | 0.02 | 0.00038 | 0.01 | 0.00116 | 0.02 | 0.00221 | 0.03 | 0.00000 | 0.00 | 0.00221 | 0.03 | |
| CV L5 | 90 | 7.9627 | 0.00256 | 0.03 | 0.00035 | 0.00 | 0.00110 | 0.01 | 0.00281 | 0.04 | 0.00000 | 0.00 | 0.00281 | 0.04 | |
| PO2(mmHg) | CV L1 | 91 | 81.1 | 2.73 | 3.37 | 1.00 | 1.23 | 1.56 | 1.92 | 3.30 | 4.07 | 0.00 | 0.00 | 3.30 | 4.07 |
| CV L2 | 90 | 91.2 | 3.34 | 3.67 | 1.31 | 1.43 | 0.84 | 0.92 | 3.69 | 4.04 | 0.00 | 0.00 | 3.69 | 4.04 | |
| CV L3 | 97 | 118.3 | 2.38 | 2.01 | 1.06 | 0.89 | 0.93 | 0.78 | 2.76 | 2.34 | 0.99 | 0.84 | 2.94 | 2.48 | |
| CV L4 | 90 | 147.3 | 2.39 | 1.62 | 2.17 | 1.48 | 2.29 | 1.56 | 3.96 | 2.69 | 0.00 | 0.00 | 3.96 | 2.69 | |
| CV L5 | 90 | 367.7 | 6.27 | 1.71 | 4.25 | 1.16 | 9.62 | 2.62 | 12.24 | 3.33 | 0.00 | 0.00 | 12.24 | 3.33 | |
| PCO2(mmHg) | CV L1 | 90 | 88.67 | 1.308 | 1.48 | 0.349 | 0.39 | 0.620 | 0.70 | 1.489 | 1.68 | 0.000 | 0.00 | 1.489 | 1.68 |
| CV L2 | 90 | 56.08 | 0.652 | 1.16 | 0.379 | 0.68 | 0.000 | 0.00 | 0.754 | 1.35 | 0.000 | 0.00 | 0.754 | 1.35 | |
| CV L3 | 96 | 29.42 | 0.332 | 1.13 | 0.173 | 0.59 | 0.033 | 0.11 | 0.376 | 1.28 | 0.000 | 0.00 | 0.376 | 1.28 | |
| CV L4 | 90 | 22.73 | 0.379 | 1.67 | 0.166 | 0.73 | 0.105 | 0.46 | 0.427 | 1.88 | 0.000 | 0.00 | 0.427 | 1.88 | |
| CV L5 | 90 | 13.17 | 0.381 | 2.89 | 0.188 | 1.43 | 0.123 | 0.93 | 0.442 | 3.36 | 0.181 | 1.37 | 0.477 | 3.63 |
{10}------------------------------------------------
iii. Precision (Whole Blood)
Whole blood precision of the i-STAT pH, PO2, and PCO2 tests in the i-STAT CG8+ cartridge on the i-STAT 1 System was evaluated using arterial, venous, and capillary1 whole blood specimens collected with lithium heparin. The whole blood precision was assessed using the duplicate test results collected across multiple point of care sites. The results are summarized in Table 4.
| Test(units) | Sample Type | Sample Range | N | Mean | SD | %CV |
|---|---|---|---|---|---|---|
| pH(pH units) | Venous WholeBlood | 6.500-7.300 | 14 | 7.0076 | 0.00378 | 0.05 |
| Venous WholeBlood | >7.300-7.450 | 95 | 7.3790 | 0.00605 | 0.08 | |
| Venous WholeBlood | >7.450-7.800 | 9 | 7.5257 | 0.00350 | 0.05 | |
| pH(pH units) | Arterial WholeBlood | 6.500-7.300 | 7 | 7.2059 | 0.00292 | 0.04 |
| Arterial WholeBlood | >7.300-7.450 | 100 | 7.3772 | 0.00574 | 0.08 | |
| Arterial WholeBlood | >7.450-7.800 | 41 | 7.4704 | 0.00585 | 0.08 | |
| pH(pH units) | Capillary WholeBlood | 6.500-7.300 | 0 | N/A | N/A | N/A |
| Capillary WholeBlood | >7.300-7.450 | 108 | 7.4075 | 0.01847 | 0.25 | |
| Capillary WholeBlood | >7.450-7.800 | 45 | 7.4729 | 0.02508 | 0.34 | |
| PO2(mmHg) | Venous WholeBlood | 10-40 | 72 | 30.5 | 0.98 | 3.21 |
| Venous WholeBlood | >40-50 | 15 | 44.7 | 0.68 | 1.53 | |
| Venous WholeBlood | >50-100 | 20 | 58.9 | 1.17 | 1.99 | |
| Venous WholeBlood | >100-250 | 5 | 141.1 | 4.72 | 3.35 | |
| Venous WholeBlood | >250-700 | 6 | 550.1 | 5.35 | 0.97 | |
| PO2(mmHg) | Arterial WholeBlood | 10-40 | 2 | 37.3 | 1.12 | 3.00 |
| Arterial WholeBlood | >40-50 | 3 | 48.2 | 1.22 | 2.54 | |
| Arterial WholeBlood | >50-100 | 61 | 76.7 | 1.26 | 1.64 | |
| Arterial WholeBlood | >100-250 | 66 | 161.2 | 3.87 | 2.40 | |
| Arterial WholeBlood | >250-700 | 15 | 323.3 | 7.45 | 2.30 | |
| PO2(mmHg) | Capillary WholeBlood | 10-40 | 5 | 36.3 | 1.52 | 4.18 |
| Capillary WholeBlood | >40-50 | 13 | 45.5 | 2.49 | 5.47 | |
| Capillary WholeBlood | >50-100 | 136 | 70.4 | 7.50 | 10.65 | |
| Capillary WholeBlood | >100-250 | 0 | N/A | N/A | N/A | |
| Capillary WholeBlood | >250-700 | 0 | N/A | N/A | N/A | |
| PCO2(mmHg) | Venous WholeBlood | 5.0-35.0 | 27 | 33.30 | 0.555 | 1.67 |
| Venous WholeBlood | >35.0-50.0 | 70 | 45.32 | 0.777 | 1.71 | |
| Venous WholeBlood | >50.0-62.5 | 14 | 55.79 | 1.592 | 2.85 | |
| Venous WholeBlood | >62.5-130.0 | 9 | 97.07 | 1.312 | 1.35 | |
| PCO2(mmHg) | Arterial WholeBlood | 5.0-35.0 | 51 | 33.76 | 0.714 | 2.12 |
| Arterial WholeBlood | >35.0-50.0 | 85 | 43.56 | 0.958 | 2.20 | |
| Arterial WholeBlood | >50.0-62.5 | 10 | 60.78 | 0.489 | 0.81 | |
| Arterial WholeBlood | >62.5-130.0 | 2 | 87.85 | 0.570 | 0.65 | |
| PCO2(mmHg) | Capillary WholeBlood | 5.0-35.0 | 51 | 31.23 | 2.048 | 6.56 |
| Capillary WholeBlood | >35.0-50.00 | 97 | 40.16 | 1.749 | 4.36 | |
| Capillary WholeBlood | >50.0-62.5 | 5 | 54.82 | 2.835 | 5.17 | |
| Capillary WholeBlood | >62.5-130 | 0 | N/A | N/A | N/A |
1 The capillary whole blood clinical precision study design involved the performance of two individual fingersticks, collected independently by two operators into two separate capillary tubes and tested on two (2) i-STAT CG8+ cartridges.
{11}------------------------------------------------
b. Linearity/assay reportable range:
Linearity i.
The study was designed based on CLSI EP06-Ed2: Evaluation of the Linearity of Quantitative Measurement Procedures - Second Edition.
The linearity of the i-STAT pH, PO2, and PCO2 tests in the i-STAT CG8+ cartridge with the i-STAT 1 System was evaluated by preparing whole blood samples of varying analyte levels for each i-STAT test. The i-STAT pH, PO2, and PCO2 tests in the i-STAT CG8+ cartridge demonstrated linearity over the reportable range for each i-STAT test. Regression summary of the response for each i-STAT test versus the concentration of the whole blood samples of varying analyte levels is provided in Table 5 for i-STAT CG8+ cartridge.
| Table 5: Regression Summary for the i-STAT pH, PO2 and PCO2 tests in the i-STAT CG8+ | ||||||
|---|---|---|---|---|---|---|
| Cartridge on the i-STAT 1 Analyzer | ||||||
| Test | Units | Reportable Range | Range Tested | Slope | Intercept | R2 |
| pH | pH units | 6.500 – 7.800 | 6.4290 – 7.8522 | 1.011 | -0.098 | 0.9994 |
| PO2 | mmHg | 5 – 700 | 4.4 – 700.0 | 0.977 | 1.062 | 0.9956 |
| PCO2 | mmHg | 5.0 – 130.0 | 2.40 – 148.38 | 1.029 | -1.144 | 0.9991 |
c. Detection Limit
i. Limit of Quantitation (LoQ)
The study was based on the CLSI EP17-A2: Evaluation of Detection Capability for Clinical Laboratory Measurement Procedures: Approved Guideline – Second Edition.
The LoQ of the i-STAT pH, PO2 and PCO2 tests in the i-STAT CG8+ cartridge was evaluated on the i-STAT 1 analyzer using two (2) i-STAT CG8+ cartridge lots and whole blood that was altered to a low analyte level for each i-STAT test. The LoQ for the i-STAT pH, PO2, and PCO2 tests in the i-STAT CG8+ cartridge and i-STAT EG7+ cartridge was determined to be at or below the lower limit of the reportable range for each of the i-STAT tests as shown in Table 6.
| Table 6: Summary of LoQ Results for i-STAT Tests in the i-STAT CG8+ Cartridge | ||
|---|---|---|
| Test (units) | Lower limit of the reportable range | Determined LoQ i-STAT CG8+ Cartridge |
| pH (pH Units) | 6.500 | 6.464 |
| PO2 (mmHg) | 5 | 5 |
| PCO2 (mmHg) | 5.0 | 3.2 |
d. Analytical Specificity
i. Interference
The study was based on CLSI EP07-ED3: Interference Testing in Clinical Chemistry, Third Edition.
The interference performance of the i-STAT pH, PO2, and PCO2 tests in the i-STAT CG8+ cartridge on the i-STAT 1 analyzer with the i-STAT 1 System was evaluated using whole blood samples based on CLSI EP07-ED3: Interference Testing in Clinical Chemistry, Third Edition. The effect of each substance was evaluated by comparing the performance of a control sample, spiked with blank solvent
{12}------------------------------------------------
solution, with the test results from a test sample spiked with the potentially interfering substance at the toxic/pathological concentration based on CLSI EP37-ED1: Supplemental Tables for Interference Testing in Clinical Chemistry, First Edition, as applicable. A substance was identified as an interferent if the difference between the control and test samples was outside of the allowable error (±Ea) for the i-STAT test. For an identified interferent, a dose-response was performed to determine the degree of interference as a function of the substance concentration.
Table 7 contains the lists of potentially interfering substances tested and the interference results for the i-STAT CG8+ cartridge.
| Table 7: Potentially Interfering Substances and Test Concentrations for the i-STAT pH, PO2, andPCO2 tests in the i-STAT CG8+ Cartridge | |||||
|---|---|---|---|---|---|
| Substance 2 | Test Concentration | i-STATTest | Interference(Yes/No) | Comments | |
| mmol/L(unlessspecified) | mg/dL(unlessspecified) | ||||
| Acetaminophen | 1.03 | 15.6 | pH | No | |
| PO2 | No | ||||
| PCO2 | No | ||||
| Atracurium(Atracurium Besylate) | 0.0287 | 3.57 | pH | No | |
| PO2 | No | ||||
| PCO2 | No | ||||
| Bilirubin | 0.684 | 40 | pH | No | |
| PO2 | No | ||||
| PCO2 | No | ||||
| Calcium(Calcium Chloride) | 5.0 | 20 | pH | No | |
| PO2 | No | ||||
| PCO2 | No | ||||
| Ethanol | 130 | 600 | pH | No | |
| PO2 | No | ||||
| PCO2 | No | ||||
| Hemoglobin | 10 g/L | 1000 | pH | No | |
| PO2 | No | ||||
| PCO2 | No | ||||
| Ibuprofen | 1.06 | 21.9 | pH | No | |
| PO2 | No | ||||
| PCO2 | No | ||||
| Intralipid 20% | N/A | 2684 | pH | No | |
| PO2 | No | ||||
| PCO2 | No | ||||
| Morphine (MorphineSodium Salt) | 0.0273 | 0.78 | pH | No | |
| PO2 | No | ||||
| PCO2 | No | ||||
| Potassium(Potassium Chloride) | 8 | 59.6 | pH | No | |
| PO2 | No | ||||
| PCO2 | No | ||||
| Sodium(Sodium Chloride) | 170 | 993.48 | pH | No | |
| PO2 | No | ||||
| PCO2 | No | ||||
| Thiopental | 1.66 | 40.2 | pH | No | |
| PO2 | No | ||||
| PCO2 | No | ||||
| Table 7: Potentially Interfering Substances and Test Concentrations for the i-STAT pH, PO2, andPCO2 tests in the i-STAT CG8+ Cartridge | |||||
| Test Concentration | |||||
| Substance 2 | mmol/L(unlessspecified) | mg/dL(unlessspecified) | i-STATTest | Interference(Yes/No) | Comments |
| Triglyceride | 16.94 | 1500 | pH | No | |
| PO2 | No | ||||
| PCO2 | No |
2 The compound tested to evaluate the interfering substance is presented in parenthesis.
{13}------------------------------------------------
ii. Other sensitivity studies
1) Altitude
The performance of the i-STAT pH, PO2 and PCO2 tests in the i-STAT CG8+ cartridge on the i-STAT 1 analyzer at an altitude of approximately 10,000 feet above sea level was evaluated using whole blood samples at relevant analyte levels across the reportable range for each test. The pH, PO2, and PCO2 results obtained from the i-STAT CG8+ cartridge on the i-STAT 1 analyzer were compared to the pH, PO2, and PCO2 results obtained from the i-STAT CG4+ (blue) cartridges on the i-STAT 1 analyzer (comparator device). Passing-Bablok regression analyses between the first replicate of the candidate device (y-axis) and mean of the comparator device (x-axis) were performed based on the CLSI EP09c: Measurement Procedure Comparison and Bias Estimation using Patient Samples, 3rd ed. The results of the correlation coefficient and slope met acceptance criteria and demonstrated equivalent performance between the candidate and comparator conditions at approximately 10,000 feet above sea level. The results are summarized in Table 8.
| Table 8: Summary of Altitude Study Results for the i-STAT CG8+ Cartridge | ||||
|---|---|---|---|---|
| Test | Correlation Coefficient (r) | Slope | ||
| r | 95% CI | Slope | 95% CI | |
| pH | 1.00 | 0.999 to 0.999 | 0.99 | 0.984 to 0.998 |
| PO2 | 1.00 | 0.994 to 0.998 | 1.02 | 1.000 to 1.037 |
| PCO2 | 1.00 | 0.997 to 0.999 | 0.98 | 0.969 to 0.989 |
B. Comparison Studies
a. Method Comparison with Comparator Device
Method comparison for arterial, venous, and capillary whole blood specimens on the i-STAT CG8+ cartridge with the i-STAT 1 System was demonstrated in studies based on CLSI EP09c-ED3: Measurement Procedure Comparison and Bias Estimation Using Patient Samples - Third Edition.
Lithium heparin venous and arterial whole blood specimens collected across multiple point of care sites were evaluated using i-STAT CG8+ cartridges on the i-STAT 1 analyzer against whole blood specimens tested on a comparative method. For pH, PO2, and PCO2, a Passing-Bablok linear regression analysis was performed using the first replicate result from the i-STAT 1 analyzer versus the singlicate result from the comparative method.
Two (2) capillary whole blood specimens collected from skin puncture with balanced heparin capillary tubes from each study subject across multiple point of care sites were evaluated and analyzed in singlicate on the i-STAT 1 analyzer against the comparative method. A Passing-Bablok linear regression analysis for pH, PO2, and PCO2 was
{14}------------------------------------------------
performed using the singlicate result from the i-STAT 1 analyzer versus the singlicate result of the comparative method.
The venous, arterial, and capillary whole blood data were pooled, and a Passing-Bablok linear regression analysis was performed using the results from the i-STAT CG8+ cartridges on the i-STAT 1 analyzer versus the comparative method results.
Method comparison results for arterial, venous, and capillary whole blood specimens are shown in Table 9. In the table, N is the number of specimens in the data set, and r is the correlation coefficient.
| Table 9: Method Comparison Results for i-STAT CG8+ Cartridge with i-STAT 1 System | |||||||
|---|---|---|---|---|---|---|---|
| Test(units) | Comparative MethodArterial/Venous/Capillary | N | Slope | Intercept | r | MedicalDecisionLevel | Bias atMedicalDecisionLevel |
| pH(pHunits) | RAPIDPoint 500/500e | 468 | 1.00 | 0.00 | 0.99 | 7.300 | -0.0040 |
| 7.350 | -0.0040 | ||||||
| 7.400 | -0.0040 | ||||||
| PO2(mmHg) | RAPIDPoint 500/500e | 461 | 1.03 | -0.72 | 0.99 | 30 | 0.1 |
| 45 | 0.5 | ||||||
| 60 | 0.9 | ||||||
| PCO2(mmHg) | RAPIDPoint 500/500e | 465 | 1.08 | -1.13 | 0.97 | 35.0 | 1.79 |
| 45.0 | 2.63 | ||||||
| 50.0 | 3.04 | ||||||
| 70.0 | 4.71 |
The method comparison results for capillary whole blood specimens only are shown in Table 10.
| Table 10: Results for i-STAT CG8+ Cartridge with i-STAT 1 System – Native and ContrivedCapillary Specimens | |||||||
|---|---|---|---|---|---|---|---|
| Test(units) | N | Slope | Intercept | r | Range | ||
| pH(pH units) | 195 | 1.02 | -0.11 | 0.98 | 6.619 - 7.772 | ||
| PO2(mmHg) | 190 | 1.02 | -1.75 | 0.99 | 12.8 - 652.6 | ||
| PCO2(mmHg) | 189 | 1.09 | -1.90 | 0.97 | 9.1 - 124.9 |
Bias at the medical decision levels for native capillary whole blood specimens only are shown in Table 11.
| Table 11: Results for i-STAT CG8+ Cartridge with i-STAT 1 System – Native CapillarySpecimens Bias at Medical Decision Levels | ||||||
|---|---|---|---|---|---|---|
| Test(units) | N | RangeMin | RangeMax | MedicalDecision Level | Bias | |
| Estimate | 95% CI | |||||
| pH(pH units) | 179 | 7.289 | 7.531 | 7.300 | -0.0160 | (-0.0352, 0.0020) |
| 7.350 | -0.0101 | (-0.0211, 0.0010) | ||||
| 7.400 | -0.0041 | (-0.0083, 0.0008) | ||||
| PO2(mmHg) | 175 | 32 | 108 | 30 | -1.8 | (-4.7, 0.9) |
| 45 | -1.3 | (-3.0, 0.2) | ||||
| 60 | -0.7 | (-1.9, 0.1) |
{15}------------------------------------------------
| Table 11: Results for i-STAT CG8+ Cartridge with i-STAT 1 System – Native CapillarySpecimens Bias at Medical Decision Levels | ||||||
|---|---|---|---|---|---|---|
| Test(units) | N | Range Min | Range Max | Medical Decision Level | Bias | |
| Estimate | 95% CI | |||||
| PCO2(mmHg) | 179 | 26.9 | 59.3 | 35.0 | 1.17 | (0.66, 1.75) |
| 45.0 | 1.79 | (0.68, 3.05) | ||||
| 50.0 | 2.11 | (0.48, 3.86) | ||||
| 70.0 | 3.36 | (-0.26, 7.08) |
b. Matrix Equivalence
A matrix equivalence study was conducted to evaluate the performance of the i-STAT pH, PO2 and PCO2 tests in the i-STAT CG8+ cartridge on the i-STAT 1 System using non-anticoagulated venous and arterial whole blood specimens. The study design and analysis method were based on recommendations from the Clinical and Laboratory Standards Institute (CLSI) guideline EP35: Assessment of Equivalence or Suitability of Specimen Types for Medical Laboratory Measurement Procedures, 1st ed. The matrix equivalence of each test in the i-STAT CG8+ cartridge was assessed by comparing arterial or venous whole blood specimens collected without anticoagulant (candidate specimen type) to samples collected with balanced heparin or lithium heparin anticoagulant (primary specimen type). Each specimen was tested in duplicate using two (2) i-STAT CG8+ cartridges with two (2) i-STAT 1 analyzers. A Passing-Bablok linear regression analysis was performed using the first replicate result from the candidate (y-axis) versus the mean result from the primary specimen (x-axis). The regression analysis results are summarized in Table 12. In the table, N is the number of specimens in the data set, and r is the correlation coefficient.
| Table 12: Matrix Equivalence Results | ||||||
|---|---|---|---|---|---|---|
| Test (units) | N | Candidate Specimen Range | Primary Specimen Range | R | Slope | Intercept |
| pH (pH units) | 241 | 7.126-7.585 | 7.130-7.607 | 0.98 | 0.97 | 0.19 |
| PO2 (mmHg) | 241 | 13-606 | 14-555 | 0.98 | 0.94 | 1.28 |
| PCO2 (mmHg) | 241 | 22.0-87.7 | 22.4-85.2 | 0.96 | 1.02 | -0.23 |
CONCLUSION VIII.
The results of these studies demonstrate that performance of the i-STAT pH, PO2, and PCO2 tests in the i-STAT CG8+ cartridge with the i-STAT 1 System are substantially equivalent to the predicate device.
§ 862.1120 Blood gases (P
CO2 , PO2 ) and blood pH test system.(a)
Identification. A blood gases (PCO2 , PO2 ) and blood pH test system is a device intended to measure certain gases in blood, serum, plasma or pH of blood, serum, and plasma. Measurements of blood gases (PCO2 , PO2 ) and blood pH are used in the diagnosis and treatment of life-threatening acid-base disturbances.(b)
Classification. Class II.