(266 days)
The i-STAT Alinity instrument with i-STAT tests is intended for use in point of care or clinical laboratory settings. The i-STAT Alinity system is intended for the quantitative measurement of various analytes in arterial and venous whole blood.
The i-STAT Hematocrit test is intended for use in the in vitro quantification of packed red blood cell volume fraction in arterial or venous heparinized whole blood, or in arterial or venous non-anticoagulated whole blood.
Hematocrit measurements can aid in the determination of normal or abnormal total red cell volume status that can be associated with conditions including anemia and erythrocytosis.
The i-STAT Hematocrit test with the i-STAT Alinity System has not been evaluated in neonates.
The i-STAT Hematocrit test with the i-STAT Alinity System is not for use with capillary samples.
For in vitro diagnostic use.
The i-STAT Alinity System is a handheld, in vitro diagnostic analytical device designed to run i-STAT test cartridges. The system is designed for use at or near point of patient care, by trained medical professionals and is for prescription use only.
The i-STAT Alinity System is comprised of the instrument, rechargeable battery, base station, electronic simulator, control material, printer and i-STAT test cartridges. The i-STAT Alinity Instrument features a barcode scanner, user interface with touch screen display and wireless capability. The instrument reports quantitative results within approximately 2 minutes.
The i-STAT test cartridge contains sensors which are located on the biosensors chips. The instrument interacts with the cartridge to move fluid across the sensors and generate a quantitative result. Cartridges require two to three drops of whole blood which are typically applied to the cartridge using a syringe.
The provided document describes the FDA 510(k) premarket notification for the i-STAT Hematocrit test with the i-STAT Alinity System. This is a point-of-care device for quantitative measurement of packed red blood cell volume fraction (hematocrit) in whole blood.
Here's an analysis of the acceptance criteria and the study proving the device meets them, based on the provided text:
Important Note: This document primarily focuses on demonstrating substantial equivalence to a predicate device (i-STAT Hematocrit test with i-STAT 1 Wireless Analyzer). Therefore, the "acceptance criteria" are largely implied by the performance characteristics demonstrated to be comparable or better than the predicate, or to fall within acceptable laboratory limits for precision, linearity, etc. There isn't an explicit table of pre-defined acceptance criteria with pass/fail thresholds in the same way one might find for, say, an AI diagnostic algorithm's sensitivity/specificity. The criteria are implicitly the successful demonstration of analytical performance, rather than clinical efficacy against a true disease state, as it's a quantitative measurement device.
1. Table of Acceptance Criteria and Reported Device Performance
As mentioned, explicit, pre-defined acceptance criteria with numerical thresholds (e.g., "sensitivity > 90%") are not stated for this type of device and submission. Instead, the acceptance is based on demonstrating sound analytical performance characteristics comparable to or better than a legally marketed predicate device. The performance data presented below indicate that the device met its internal performance specifications, which are implicitly the "acceptance criteria" for this submission type.
| Performance Characteristic | Implicit Acceptance Criteria (based on common lab standards/comparison to predicate) | Reported Device Performance |
|---|---|---|
| Precision (Aqueous Materials) | Acceptable within-run, between-run, and total precision (%CV and SD) for a hematocrit measuring device. | CV L2 (16.9%PCV): ST 0.46, CVt 2.72%; Sr 0.44, CVr 2.60%; Srr 0.09, CVrr 0.53%; Sdd 0.09, CVdd 0.53% CV L3 (33.9%PCV): ST 0.51, CVt 1.50%; Sr 0.48, CVr 1.42%; Srr 0.13, CVrr 0.38%; Sdd 0.11, CVdd 0.32% CV L4 (55.2%PCV): ST 0.49, CVt 0.89%; Sr 0.47, CVr 0.85%; Srr 0.12, CVrr 0.22%; Sdd 0.09, CVdd 0.16% CV L5 (65.0%PCV): ST 0.39, CVt 0.60%; Sr 0.37, CVr 0.57%; Srr 0.10, CVrr 0.15%; Sdd 0.09, CVdd 0.14% |
| Precision (Whole Blood) | Acceptable within-instrument and total precision (%CV and SD) across different hematocrit levels at multiple sites. | Abnormal Low (< 38%PCV): Total SD 0.51, %CV 1.49 (Site 1); Total SD 0.44, %CV 1.24 (Site 2); Total SD 0.50, %CV 1.45 (Site 4) Normal (38-51%PCV): Total SD 0.51, %CV 1.13 (Site 1); Total SD 0.52, %CV 1.22 (Site 2); Total SD 0.44, %CV 1.03 (Site 4) Abnormal High (> 51%PCV): Total SD 0.48, %CV 0.88 (Site 1); Total SD 0.30, %CV 0.57 (Site 2); Total SD 0.22, %CV 0.41 (Site 4) |
| Linearity | Demonstration of linearity across the claimed reportable range (15 - 75 %PCV) with an appropriate regression model. | Demonstrated over the reportable range (15 - 75 %PCV). Best fitting regression was a third-order model, with non-linearity ranging from 0.19 to 0.81 %PCV. (This is generally considered acceptable if the non-linearity is small enough.) |
| Recovery | Acceptable percentage recovery across the reportable range. | % recovery ranged from 100.1% to 102.8%. (This is a very good recovery range, indicating accurate measurement across the range.) |
| Limit of Quantitation (LoQ) | LoQ should be at or below the claimed low end of the reportable range. | LoQ determined to be 14.0 %PCV, which is less than the low end of the reportable range (15 %PCV). (Meets criteria.) |
| Interference | Identification of compounds that do/do not interfere within specified concentrations (difference from reference > 10.8% of mean reference value). | Non-interfering: Bromide (< 37.5 mmol/L), Bilirubin (≤ 0.342 mmol/L), Sodium Thiosulfate (≤ 6.7 mmol/L), Triglyceride (≤ 37 mmol/L), White Blood Cells (21,700 WBC/μL). Interfering: Total Protein (> 12 g/dL) at 26.5-31.5 %PCV Hct level; White Blood Cells (> 50,000 WBC/µL) at 26.5-31.5 %PCV Hct level. (Crucial information for labeling and use.) |
| Anticoagulant Study | Comparability between heparinized and non-anticoagulated whole blood samples. | Deming regression results: slope of 1.00 and correlation coefficient of 1.00. (Indicates excellent agreement.) |
| Microhematocrit Reference Study | Strong correlation and negligible bias when compared to the microhematocrit reference method (K2EDTA). | Deming regression: slope of 1.02, intercept of -0.53, R² of 1.00 (vs K2EDTA reference); and slope of 1.02, intercept of -0.41, R² of 1.00 (vs K2EDTA microhematocrit). (Indicates excellent agreement.) |
| Method Comparison with Predicate Device | Strong correlation and agreement between the new device and the predicate device across the reportable range. | Weighted Deming regression for all 3 sites combined: slope of 1.016 and correlation coefficient (r) of 0.995. (Indicates very strong agreement, supporting substantial equivalence.) |
2. Sample Size Used for the Test Set and Data Provenance
For a quantitative measurement device like this, there isn't a single "test set" in the context of an AI model. Instead, various test samples are used for different analytical performance studies:
- Precision (Aqueous Materials): 4 levels of aqueous materials tested over 20 days. N=80 for each level (total of 320 measurements).
- Precision (Whole Blood): Venous whole blood samples (native or altered) at low abnormal, normal, and high abnormal hematocrit levels. N=21 for each level at each of 3 sites (total of 9 samples, each tested 21 times, so 9 * 21 = 189 measurements described in the table, across an unspecified total number of individual blood samples).
- Linearity: A series of whole blood samples used to span the reportable range. (Specific N not provided, but typically would involve multiple dilutions).
- Recovery: A series of whole blood samples spanning the reportable range. (Specific N not provided).
- Limit of Quantitation (LoQ): Whole blood samples altered to low hematocrit levels (< 15 %PCV). (Specific N not provided).
- Interference: Whole blood test samples. (Specific N not provided, but "Testing was conducted at two hematocrit levels" implies multiple samples for each compound).
- Anticoagulant Study: 40 blood samples spanning the reportable range (15 to 75 %PCV).
- Microhematocrit Reference Study: 40 lithium heparinized whole blood samples spanning the reportable range (15 to 75 %PCV).
- Method Comparison with Predicate Device: 240 whole blood (venous or arterial) samples covering the reportable range (15 to 75 %PCV).
Data Provenance:
- Country of Origin: Not explicitly stated, but the submission is to the U.S. FDA, and the company (Abbott Point of Care, Inc.) is based in Princeton, NJ, implying a U.S. context for the studies.
- Retrospective/Prospective: These are analytical performance studies using prepared samples or patient samples collected specifically for the study. Therefore, they are prospective in nature, as the data collection and measurements were conducted specifically for the purpose of validating the device performance.
- Sites:
- Precision (Aqueous Materials): One site.
- Precision (Whole Blood): 3 point-of-care sites.
- Method Comparison with Predicate Device: 3 point-of-care sites.
- Other studies: Sites not specified, but implied to be laboratory or clinical settings.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts
For a quantitative measurement device like the i-STAT Hematocrit test, "ground truth" is typically established by:
- Reference Methods: Such as the microhematocrit method, which is a gold standard for hematocrit measurement.
- Predicate Device Measurements: Used for method comparison studies to show equivalence.
- Preparation of Spiked/Altered Samples: Where the known concentration/value is set by the preparation method.
Experts Required: The studies are primarily laboratory-based analytical evaluations. Therefore, the "ground truth" is not established by human readers/experts interpreting medical images or clinical data, but by established laboratory instrumentation and validated methods. The qualifications would be typical laboratory personnel, scientists, and statisticians who conduct and analyze such studies according to CLSI guidelines. The document does not specify a number of "experts" as it would for, e.g., radiology image interpretation.
4. Adjudication Method for the Test Set
Adjudication methods (like 2+1, 3+1) are common in studies where multiple human readers interpret data, and a consensus or majority rule is needed to establish ground truth for ambiguous cases. This is not applicable here because the ground truth for hematocrit measurements is established by quantitative reference methods and chemical/biological preparations, not by human interpretation or consensus.
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done
No, an MRMC study was not done. MRMC studies are specific to evaluating devices that assist human readers in tasks like image interpretation (e.g., radiologists reading scans with or without AI). The i-STAT Hematocrit test is a standalone quantitative measurement device; it does not assist a human reader in making a diagnosis or interpretation in the same way an AI for image analysis would. Its effectiveness is assessed by its measurement accuracy, precision, and agreement with reference methods and predicate devices.
Effect Size: Not applicable as it's not a human-in-the-loop diagnostic AI.
6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) Was Done
Yes, the studies reported are 'standalone' performance studies for the device. The i-STAT Alinity System with the Hematocrit test cartridge takes a blood sample and provides a quantitative result. The performance characteristics described (precision, linearity, LoQ, interference, recovery, method comparisons) all evaluate the device's ability to accurately and reliably measure hematocrit on its own, without human real-time intervention or interpretation of its output in a diagnostic workflow (beyond reading the numerical result).
7. The Type of Ground Truth Used
The ground truth for the analytical performance studies was established through:
- Reference Methods: Primarily the microhematocrit method (K2EDTA reference), which is a widely accepted laboratory standard for determining packed red blood cell volume.
- Predicate Device Output: For method comparison studies, the results from the legally marketed i-STAT Hematocrit test with the i-STAT 1 Wireless Analyzer served as a comparative "ground truth" or reference.
- Prepared Samples: For studies like linearity, recovery, and LoQ, the "ground truth" concentrations or values are precisely prepared in the laboratory.
- Spiked Samples: For interference studies, samples were spiked with known concentrations of potentially interfering substances.
8. The Sample Size for the Training Set
This document describes the regulatory submission (510(k)) and performance studies for a medical device (a hematocrit measuring instrument and its test cartridge). It is not an AI/ML device in the typical sense that would require a "training set" for model development. The measurement principle is based on a conductivity method, not a learned algorithm trained on data. Therefore, the concept of a "training set" is not applicable to this device.
9. How the Ground Truth for the Training Set Was Established
As explained above, there is no "training set" for this type of device. The ground truth for the test samples (used to evaluate performance) was established by reference methods, predicate device results, and precise laboratory preparation as detailed in point 7.
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Food and Drug Administration 10903 New Hampshire Avenue Document Control Center - WO66-G609 Silver Spring, MD 20993-0002
August 22, 2017
Abbott Point of Care, Inc. Laura Y. Joglekar Associate Director, Regulatory Affairs 400 College Road East Princeton, NJ 08540
Re: K163342
Trade/Device Name: i-STAT Hematocrit test with i-STAT Alinity System Regulation Number: 21 CFR 864.6400 Regulation Name: Hematocrit measuring device Regulatory Class: Class II Product Code: JPI Dated: July 24, 2017 Received: July 25, 2017
Dear Ms. Joglekar:
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 Part 801); medical device reporting (reporting of medical
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device-related adverse events) (21 CFR 803); good manufacturing practice requirements as set forth in the quality systems (QS) regulation (21 CFR Part 820); and if applicable, the electronic product radiation control provisions (Sections 531-542 of the Act); 21 CFR 1000-1050.
If you desire specific advice for your device on our labeling regulation (21 CFR Part 801), 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/Resourcesfor You/Industry/default.htm. Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21CFR 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,
Leonthena R. Carrington -S
Lea Carrington 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) K163342
Device Name
i-STAT Hematocrit test with the i-STAT Alinity System
Indications for Use (Describe)
The i-STAT Alinity instrument with i-STAT tests is intended for use in point of care or clinical laboratory settings. The i-STAT Alinity system is intended for the quantitative measurement of various analytes in arterial and venous whole blood.
The i-STAT Hematocrit test is intended for use in the in vitro quantification of packed red blood cell volume fraction in arterial or venous heparinized whole blood, or in arterial or venous non-anticoagulated whole blood.
Hematocrit measurements can aid in the determination of normal or abnormal total red cell volume status that can be associated with conditions including anemia and erythrocytosis.
The i-STAT Hematocrit test with the i-STAT Alinity System has not been evaluated in neonates.
The i-STAT Hematocrit test with the i-STAT Alinity System is not for use with capillary samples.
For in vitro diagnostic use.
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
The information in this 510(k) summary is being submitted in accordance with the requirements of 21 CFR 807.92.
| 1. Submitter Information | |
|---|---|
| Owner | Abbott Point of Care Inc.400 College Road EastPrinceton, NJ 08540 |
| Contact | Primary: Laura JoglekarAssociate Director, Regulatory Affairslaura.joglekar@abbott.comPhone: 609-454-9327Secondary: Susan TibedoDirector, Regulatory Affairssusan.tibedo@abbott.comPhone: 609-454-9360 |
| Date Prepared | July 24, 2017 |
2. Device Information
Proprietary Name
i-STAT Hematocrit test with the i-STAT Alinity System
| Productcode | Device Classificationname | RegulationNumber | Class | Panel |
|---|---|---|---|---|
| JPI | Device, HematocritMeasuring | 864.6400 | II | Hematology |
| JGS | Electrode, Ion Specific,Sodium | 862.1665 | II | Clinical Chemistry |
3. Predicate Device
Proprietary Name 510(k) Number
i-STAT Hematocrit test with i-STAT 1 Wireless Analyzer K103195
| Productcode | Device Classificationname | RegulationNumber | Class | Panel |
|---|---|---|---|---|
| JPI | Device, HematocritMeasuring | 864.6400 | II | Hematology |
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4. Device Description
The i-STAT Alinity System is a handheld, in vitro diagnostic analytical device designed to run i-STAT test cartridges. The system is designed for use at or near point of patient care, by trained medical professionals and is for prescription use only.
The i-STAT Alinity System is comprised of the instrument, rechargeable battery, base station, electronic simulator, control material, printer and i-STAT test cartridges. The i-STAT Alinity Instrument features a barcode scanner, user interface with touch screen display and wireless capability. The instrument reports quantitative results within approximately 2 minutes.
The i-STAT test cartridge contains sensors which are located on the biosensors chips. The instrument interacts with the cartridge to move fluid across the sensors and generate a quantitative result. Cartridges require two to three drops of whole blood which are typically applied to the cartridge using a syringe.
5. Intended Use Statement
Instrument
The i-STAT Alinity instrument with i-STAT tests is intended for use in point of care or clinical laboratory settings. The i-STAT Alinity system is intended for the quantitative measurement of various analytes in arterial and venous whole blood. For in vitro diagnostic use.
Test
The i-STAT Hematocrit test is intended for use in the in vitro quantification of packed red blood cell volume fraction in arterial or venous heparinized whole blood, or in arterial or venous nonanticoagulated whole blood.
Hematocrit measurements can aid in the determination and monitoring of normal or abnormal total red cell volume status that can be associated with conditions including anemia and erythrocytosis.
The i-STAT Hematocrit test with the i-STAT Alinity System has not been evaluated in neonates.
The i-STAT Hematocrit test with the i-STAT Alinity System is not for use with capillary samples.
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| Similarities and Differences: System (Test and Instrument) | ||
|---|---|---|
| Feature orCharacteristic | Predicate Device (K103195):i-STAT Hematocrit test withthe i-STAT1 Wireless Analyzer | Candidate Device:i-STAT Hematocrit test withthe i-STAT Alinity instrument |
| Intended Use:Instrument | The i-STAT 1 Wireless Analyzeris used by trained medicalprofessionals for running avariety of clinical chemistry testsand test panels contained ini-STAT test cartridges. | The i-STAT Alinity instrumentwith i-STAT tests is intended foruse in point of care or clinicallaboratory settings. The i-STATAlinity system is intended for thequantitative measurement ofvarious analytes in arterial andvenous whole blood.For in vitro diagnostic use. |
| Intended Use:Test | The test for hematocrit, as part ofthe i-STAT System, is intendedfor use in the in vitroquantification of packed redblood cell volume fraction inarterial, venous, or capillarywhole blood. | The i-STAT Hematocrit test isintended for use in the in vitroquantification of packed redblood cell volume fraction inarterial or venous heparinizedwhole blood, or in arterial orvenous non-anticoagulatedwhole blood. |
| Hematocrit measurements canaid in the determination andmonitoring of normal orabnormal total red cell volumestatus including, but not limitedto, conditions such as anemia,erythrobytosis, and blood lossrelated to trauma a surgery. | Hematocrit measurements canaid in the determination andmonitoring of normal orabnormal total red cell volumestatus that can be associated withconditions including anemia anderythrocytosis.The i-STAT Hematocrit test withthe i-STAT Alinity System hasnot been evaluated in neonates.The i-STAT Hematocrit test withthe i-STAT Alinity System is notfor use with capillary samples. | |
| Similarities and Differences: System (Test and Instrument) | ||
| Feature orCharacteristic | Predicate Device (K103195):i-STAT Hematocrit test withthe i-STAT1 Wireless Analyzer | Candidate Device:i-STAT Hematocrit test withthe i-STAT Alinity instrument |
| Principle ofMeasurement | Hematocrit is measured using theconductivity method. | Same |
| Calibration | 1-point on-board (containedwithin the cartridge) | Same |
| TestTraceability | Microhematocrit Method | Same |
| Test ReportableRange | 15 – 75 %PCV | Same |
| Sample Type | Fresh capillary, arterial or venouswhole blood. | Fresh arterial or venous wholeblood. |
| Sample Volume | 65 - 95 μL | Same |
| Time to test | ~2 minutes | Same |
| Test Format | Cartridge | Same |
| Test preparation | Ready to use | Same |
| Test Storageand Stability | Storage: 2°C to 8°C (35-46°F) | Same |
| Quality Checks | A series of quality checks areautomatically run each test cycleprior to the system generating aresult. Quality checks verify theanalyzer motor, electrical,pressure and temperature systemsand cartridge elements. | Same |
| Wirelessconnectivitycapability | Yes | Same |
| Power | Two 9-volt lithium batteries, orrechargeable battery. | Lithium-Ion rechargeable battery |
6. Summary Comparision of Technological Characteristics
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| Similarities and Differences: System (Test and Instrument) | |||||||
|---|---|---|---|---|---|---|---|
| Feature orCharacteristic | Predicate Device (K103195):i-STAT Hematocrit test withthe i-STAT1 Wireless Analyzer | Candidate Device:i-STAT Hematocrit test withthe i-STAT Alinity instrument | |||||
| Barcodescanningcapability | Yes | Same | |||||
| Data storagecapability | Yes | Same | |||||
| User Interface | 19 keys for data entry | LCD touch screen | |||||
| User InterfaceScreen | A grey scale LCD (3.5 in.) | A color LCD screen (5 in.) |
7. Performance Characteristics
a. Precision
Precision 20 days (aqueous materials)
The precision of the i-STAT Hematocrit test on the i-STAT Alinity Instrument was evaluated using 4 levels of aqueous materials. This 20-day precision testing was based on CLSI document EP5-A3: Evaluation of Quantitative Measurement Procedures; Approved Guideline – Third Edition. The study was conducted using 10 instruments and one test cartridge lot over 20 days at one site. The results of the 20-day precision study using all test results are shown in Table 1.
| Fluid | N | Mean(%PCV) | ST(%PCV) | CVT | Sr(%PCV) | CVr | Srr(%PCV) | CVrr | Sdd(%PCV) | CVdd |
|---|---|---|---|---|---|---|---|---|---|---|
| CV L2 | 80 | 16.9 | 0.46 | 2.72% | 0.44 | 2.60% | 0.09 | 0.53% | 0.09 | 0.53% |
| CV L3 | 80 | 33.9 | 0.51 | 1.50% | 0.48 | 1.42% | 0.13 | 0.38% | 0.11 | 0.32% |
| CV L4 | 80 | 55.2 | 0.49 | 0.89% | 0.47 | 0.85% | 0.12 | 0.22% | 0.09 | 0.16% |
| CV L5 | 80 | 65.0 | 0.39 | 0.60% | 0.37 | 0.57% | 0.10 | 0.15% | 0.09 | 0.14% |
Table 1: 20-day Precision Study Results
Precision (whole blood)
The whole blood precision of the i-STAT Hematocrit Test on the i-STAT Alinity Instrument was evaluated using venous whole blood (native or altered) samples targeted to be within a low abnormal, normal and high abnormal hematocrit levels.
One test cartridge lot was used across 3 point of care sites. At each site, each sample was tested 3 times on each of 7 i-STAT Alinity Instruments (total of 21 test results per sample). The results of the whole blood precision study are shown in Table 2.
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| Level (%PCV) | Site | N | Mean(%PCV) | Within-Instrument | Total | ||
|---|---|---|---|---|---|---|---|
| SD | %CV | SD | %CV | ||||
| < 38(abnormal low) | 1 | 21 | 34.6 | 0.44 | 1.26 | 0.51 | 1.49 |
| 2 | 21 | 35.2 | 0.44 | 1.24 | 0.44 | 1.24 | |
| 4 | 21 | 34.4 | 0.49 | 1.42 | 0.50 | 1.45 | |
| 38 – 51(normal) | 1 | 21 | 45.5 | 0.49 | 1.07 | 0.51 | 1.13 |
| 2 | 21 | 42.5 | 0.44 | 1.03 | 0.52 | 1.22 | |
| 4 | 21 | 42.2 | 0.44 | 1.03 | 0.44 | 1.03 | |
| > 51(abnormal high) | 1 | 21 | 54.9 | 0.44 | 0.80 | 0.48 | 0.88 |
| 2 | 21 | 53.1 | 0.30 | 0.57 | 0.30 | 0.57 | |
| 4 | 21 | 53.0 | 0.22 | 0.41 | 0.22 | 0.41 |
Table 2: Whole Blood Precision Results
b. Linearity
The study was based on CLSI EP06-A: Evaluation of the linearity of quantitative measurement procedures; Approved Guideline. The linearity of the i-STAT Hematocrit test was evaluated on the i-STAT Alinity Instrument by preparing a series of whole blood samples with hematocrit levels that spanned the reportable range of the test. The best fitting regression model was a third order model, and the absolute value of the non-linearity ranged from 0.19 to 0.81 %PCV. The linearity of the i-STAT Hematocrit test used with the i-STAT Alinity Instruments was demonstrated over the reportable range (15 - 75 %PCV).
c. Recovery
The recovery of the i-STAT Hematocrit test was evaluated on the i-STAT Alinity Instrument by by preparing a series of whole blood samples with hematocrit levels that spanned the reportable range of the test, measuring their expected value on the predicate device and determining the % recovery. The % recovery ranged from 100.1% to 102.8%.
d. 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 Hematocrit test was evaluated on the i-STAT Alinity Instrument using whole blood samples that were altered to low hematocrit levels (< 15 %PCV) and two test cartridge lots. The LoQ for the i-STAT Hematocrit test on the i-STAT Alinity Instrument was determined to be 14.0 %PCV, which is less than the low end of the reportable range of the test (15 %PCV).
e. Interference
The interference performance of the i-STAT Hematocrit test on the i-STAT Alinity Instrument was evaluated using whole blood test samples based on CLSI EP07-A2: Interference Testing in Clinical Chemistry; Approved Guideline – Second Edition. The effect of each potentially interfering compound was evaluated by comparing the i-STAT Hematocrit results of a test sample spiked to a high concentration of the compound and the reference method result for the same sample. Testing was conducted at two hematocrit levels. A compound was identified as an interferent if the 95% confidence interval on the difference between the spiked test sample and the reference was > 10.8% of the mean reference value. Compounds that do not interfere with
i-STAT Hematocrit Test with the i-STAT Alinity System
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the hematocrit test are shown in Table 3; those compounds that do interfere are shown in Table 4.
| Compound | Test Concentration(mmol/L) | Test Concentration(mg/dL) |
|---|---|---|
| Bromide** | < 37.5 | < 325.69 |
| Bilirubin | ≤ 0.342 | ≤ 20.01 |
| Sodium Thiosulfate | ≤ 6.7 | ≤ 264.04 |
| Triglyceride | ≤ 37 | ≤ 3233.80 |
| White Blood Cells | 21 700 WBC/μL |
Table 3: Non-Interfering Compounds and Test Concentrations
*Concentrations less than the test concentrations do not interfere
** Bromide (37.5 mmol/L) is an interferent with the sodium test and it may result in an increased rate of star outs (***) for the hematocrit test.
Table 4: Interfering Compounds and Interfering Concentrations
| Compound | TestConcentration | Hematocrit Level(% PCV) | Result |
|---|---|---|---|
| Total Protein(human serum albumin) | >12 (g/dL) | 26.5 - 31.5* | Interfering |
| Total Protein(human serum albumin) | >12 (g/dL) | 57 - 63** | Non-interfering |
| White Blood Cells | > 50,000WBC/µL | 26.5 - 31.5 * | Interfering |
*Concentrations greater than the test concentrations do interfere
**Concentrations less than the test concentrations do not interfere
f. Anticoagulant Study
The sample type comparison study was performed using the i-STAT Hematocrit test on the i-STAT Alinity Instrument and 40 blood samples spanning the reportable range, 15 to 75 %PCV. The comparator condition for this study was heparinized whole blood and the test condition was non-anticoagulated whole blood. The Deming regression results were a slope of 1.00 and a correlation coefficient of 1.00.
g. Microhematocrit Reference Study
The microhematocrit reference study was performed using the i-STAT Hematocrit test on the i-STAT Alinity Instrument and 40 lithium heparinized whole blood samples spanning the reportable range, 15 to 75 %PCV. Two comparator conditions for this study were used: the K2EDTA and K2EDTA microhematocrit results for the 40 whole blood samples. The Deming regression of the i-STAT Hematocrit results (traceable to K2EDTA reference) to the K2EDTA microhematocrit results gave a slope of 1.02, an intercept of -0.53 and a coefficient of
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determination (R2) of 1.00.The Deming regression of the i-STAT Hematocrit results (traceable to K2EDTA reference) to the K2EDTA microhematocrit results gave a slope of 1.02, an intercept of -0.41 and a coefficient of determination (R2) of 1.00.
h. Method Comparison with Predicate Device
The method comparison study compared the clinical results of the i-STAT Hematocrit test on the i-STAT Alinity Instrument to the results of the i-STAT Hematocrit test on the i-STAT 1 Wireless Analyzer (predicate). The study was conducted across 3 point of care sites. The study included 240 whole blood (venous or arterial) samples covering the reportable range, 15 to 75 %PCV. The Weighted Deming regression for all 3 sites combined had a regression slope of 1.016 and correlation coefficient (r) of 0.995.
8. Conclusion
Analytical and clinical studies have shown the i-STAT Hematocrit test with the i-STAT Alinity System to be safe and effective for its intended use. The results of these studies demonstrate that performance of the i-STAT Hematocrit test with the i-STAT Alinity System is substantially equivalent to the predicate device.
§ 864.6400 Hematocrit measuring device.
(a)
Identification. A hematocrit measuring device is a system consisting of instruments, tubes, racks, and a sealer and a holder. The device is used to measure the packed red cell volume in blood to determine whether the patient's total red cell volume is normal or abnormal. Abnormal states include anemia (an abnormally low total red cell volume) and erythrocytosis (an abnormally high total red cell mass). The packed red cell volume is produced by centrifuging a given volume of blood.(b)
Classification. Class II (special controls). The device is exempt from the premarket notification procedures in subpart E of part 807 of this chapter subject to § 864.9.