(17 days)
The i-STAT lactate test is useful for (1) the diagnosis and treatment of lactic acidosis in conjunction with measurements of blood actifbase status, (2) monitoring tissue hypoxia and strenuous physical exertion, and (3) diagnosis of hyperlactatemia.
The i-STAT lactate test is contained in a single use cartridge. In use, two to three drops of blood are placed in the cartridge as described below. The cartridge is inserted into the thermally controlled i-STAT Model 200 Portable Clinical Analyzer and all analytical steps are performed automatically. Patient and user information may be entered into the analyzer via a keypad during the automated analysis cycle. The i-STAT System is an in vitro analytical system comprising a network of one or more portable clinical analyzers designed to be used at the point of patient care. The analyzers employ single-use test cartridges containing biosensor chips to perform diagnostic tests on whole blood. The system further comprises an infrared communications link from the analyzers to auxiliary information management devices such as printers, personal computers, laboratory information systems and hospital information systems. The i-STAT analyzers, as part of the i-STAT System, are intended for use by health-care professionals for the in vitro analysis of arterial, venous or capillary whole blood at the point of patient care. Tests with the i-STAT System are carried out in test cartridge. It houses the sensor array, aqueous calibrator, fluid channels, and a waste reservoir). Electrochemical sensors on biosensor chips are housed in cartridges in a variety of sensor test configurations appropriate to clinical needs. Test panels are identified by name and color code on the cartridge label. In addition, test panel configurations are encoded into the cartridge in a mechanical feature in the cartridge housing. An array of electrical pins in the analyzer recognizes the mechanical feature and automatically identifies the cartridge test panel type. In use, whole blood is introduced into the sample well of the cartridge at the sample port. After closure, the cartridge is inserted into the cartridge door of the analyzer. Insertion of the cartridge initiates a precisely controlled and monitored sequence of steps performed by the instrument without user intervention. These steps are: - Electrical contact is made between the analyzer electronic input circuits and the . The analyzer identifies the type of cartridge being used and the tests cartridge. contained in the cartridge. - Calibrator is positioned over the sensors. Each lactate test is calibrated with calibrator . fluid that contains a pre-determined amount of lactic acid. - Calibration measurements are made as the sensors generate signals mathematically . related to analytic concentrations. In the i-STAT lactate test the concentration of lactate is directly related to the appearance of hydrogen peroxide (measured by amperometrically) generated by lactic acid oxidase acting on lactic acid in the calibrator fluid or in the blood sample. - . Blood sample washes out the calibrator with the aid of an air bubble between the two. - . Blood sample is positioned over the sensors. - . Calculations of sample concentrations are performed and displayed. The displayed results are also stored in the analyzer memory and can be transmitted by infrared communication link to commercially available computers or printers. The lactate test cartridge is assembled from plastic components that provide the conduits for fluid handling and house the sensor chips. In the cartridge containing the test for lactate, the sensors comprise a patterned metallic layer, supported on a silicon/silicon dioxide substrate, coated with a thin membrane containing lactic acid oxidase.
Here's a breakdown of the acceptance criteria and the study details for the i-STAT Lactate test, based on the provided 510(k) summary:
Acceptance Criteria and Device Performance for i-STAT Lactate Test
1. Table of Acceptance Criteria and Reported Device Performance
The provided document describes a predicate device comparison study rather than explicitly stating acceptance criteria in advance. However, the "conclusions" section confirms that the device meets established standards by being substantially equivalent to the predicate. The performance comparisons provided serve as the basis for this determination.
| Acceptance Criterion (Inferred from Predicate Equivalence) | Reported i-STAT Lactate Performance |
|---|---|
| Linearity Range | 0.3 to 20 mmol/L |
| Imprecision (Normal Range) | 0.81 ± 0.03 mmol/L [3.3% c.v.] |
| Imprecision (Abnormal Range) | 6.35 ± 0.08 mmol/L [1.2% c.v.] |
| Correlation to Predicate Device (Blood) | Slope: 0.993, Intercept: 0.036, r: 0.998 (N=46) |
| Correlation to Standard Lab Instrument (Plasma) | Slope: 1.118, Intercept: -0.052, r: 0.998 (N=47) |
| Medical Allowable Error | Within standards accepted by the medical community (based on CAP Surveys) |
2. Sample Size and Data Provenance for Test Set
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Sample Size (Test Set):
- Clinical Comparison - Blood: 46 patient samples
- Clinical Comparison - Plasma: 47 patient samples
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Data Provenance: The document does not explicitly state the country of origin or whether the data was retrospective or prospective. It refers to "patient samples" and "sites" (Site 1 for blood comparison, Site 2 for plasma comparison), implying clinical data rather than simulated. Without further detail, it's difficult to categorize definitively.
3. Number of Experts and Qualifications for Ground Truth
The document does not mention the use of experts to establish ground truth for the clinical comparison. The "ground truth" was established by comparison to existing, cleared analytical devices (the predicate device and a standard laboratory instrument).
4. Adjudication Method for Test Set
No adjudication method is described. The comparison is directly between the i-STAT device and the reference devices.
5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study
No MRMC comparative effectiveness study was performed. This device is an in vitro diagnostic (IVD) for measuring a analyte; therefore, human reader improvement with AI assistance is not applicable.
6. Standalone (Algorithm Only) Performance
Yes, a standalone performance was done. The study evaluates the i-STAT Lactate test (the algorithm/device) directly against established methods without human interpretation of results influencing the primary analytical performance.
7. Type of Ground Truth Used
The ground truth for the clinical test set was established by comparison to existing, cleared analytical devices:
- Predicate Device: Stat Profile® Plus Ultra/Lactic acid test (for whole blood comparison).
- Standard Laboratory Instrument: (unspecified, but used for plasma comparison).
8. Sample Size for Training Set
The document does not explicitly mention a "training set" in the context of machine learning or AI. The i-STAT Lactate test is an IVD device based on biosensor technology. Its performance is characterized through:
- Non-clinical studies: Calibration verification solutions (5 concentrations) and aqueous controls (N=120 for normal range, N=120 for abnormal range) were used to establish linearity and imprecision.
- Clinical studies: Blood and plasma samples from patients were used for comparison.
There is no mention of a "training set" in the sense of data used to train a predictive model.
9. How Ground Truth for Training Set was Established
As there is no explicit mention of a "training set" in the context of AI/ML, this question is not directly applicable. For the non-clinical studies (linearity, imprecision), the ground truth was established by using known concentrations of lactic acid in calibration verification solutions and aqueous controls.
§ 862.1450 Lactic acid test system.
(a)
Identification. A lactic acid test system is a device intended to measure lactic acid in whole blood and plasma. Lactic acid measurements that evaluate the acid-base status are used in the diagnosis and treatment of lactic acidosis (abnormally high acidity of the blood).(b)
Classification. Class I (general controls). The device is exempt from the premarket notification procedures in subpart E of part 807 of this chapter subject to § 862.9.