(83 days)
The DRI® Cotinine Enzyme Immunoassay is intended for the Qualitative and Semi-Quantitative determination of Cotinine in human urine at a cutoff level of 500 ng/mL. This assay is intended for in vitro diagnostic use only. The assay is intended as an aid in the detection of cotinine after use or exposure to tobacco products.
The DRI® Cotinine EIA Assay is a liquid ready-to-use homogeneous enzyme immunoassay. The assay uses specific antibodies, which can detect cotinine drugs in urine. The assay is based on competition between a drug labeled with glucose-6-phosphate dehydrogenase (G6PDH) enzyme, and free drug from the urine sample for a fixed amount of specific antibody binding sites. In the absence of free drug from the sample. the specific antibody binds the drug labeled with G6PDH causing a decrease in enzyme activity. This phenomenon creates a direct relationship between drug concentration in urine and enzyme activity. The enzyme G6PDH activity is determined spectrophotometrically at 340 nm by measuring its ability to convert nicotinamide adenine dinucleotide (NAD) to NADH.
Here's an analysis of the provided K030649 document regarding the acceptance criteria and the study proving the device meets them:
1. Table of Acceptance Criteria and Reported Device Performance
The document provides performance data, but it does not explicitly state pre-defined acceptance criteria for most metrics. The comparison is made against a predicate device and general good laboratory practice.
| Performance Metric | Acceptance Criteria (Implicit/Inferred) | Reported Device Performance (DRI® Cotinine EIA Assay) |
|---|---|---|
| Accuracy | Comparable to predicate device (93.6% sens, 74.0% spec) and high agreement with reference method | 98% Total Agreement (110 true positives, 80 true negatives) against GC/MS reference method. |
| Sensitivity (LOD) | Good sensitivity (not explicitly quantified as an acceptance criterion) | 34 ng/mL |
| Precision | Not explicitly quantified as an acceptance criterion, but good reproducibility is expected. | %CVs for total and within-run testing were ≤ 9.4% (at critical points of measurement range). |
| Specificity | Not affected by common interfering substances. | Not affected by common endogenous substances, variations in urinary pH levels, structurally unrelated pharmaceutical compounds, or potentially cross-reacting compounds. |
2. Sample Size Used for the Test Set and Data Provenance
The document states:
- Accuracy Study Test Set: The accuracy study reported "110 true positives, 80 true negatives", implying a total of 190 samples were used in this specific comparison.
- Precision Study Test Set: No specific sample size is given for the precision study, only that it was conducted at 3 analyte concentration levels (300 ng/mL, 500 ng/mL, and 700 ng/mL).
- Sensitivity (LOD) Study Test Set: Not specified.
- Specificity Study Test Set: Not specified.
Data Provenance: The document does not explicitly state the country of origin for the data or whether the studies were retrospective or prospective. Given the nature of a 510(k) submission for an IVD, these are typically laboratory-based validation studies.
3. Number of Experts Used to Establish Ground Truth for the Test Set and Qualifications
- Accuracy Study Ground Truth: The ground truth for the accuracy study was established using a GC/MS (Gas Chromatography/Mass Spectrometry) reference method. This is a highly accurate and widely accepted analytical technique for confirming the presence and concentration of substances. Therefore, human experts were not directly establishing the ground truth for individual samples; rather, the GC/MS result served as the objective truth.
- Other Studies: Not applicable as these studies (precision, sensitivity, specificity) evaluate the device's technical performance characteristics rather than a diagnostic decision against a clinical truth.
4. Adjudication Method for the Test Set
Not applicable. As the ground truth for accuracy was established by a reference laboratory method (GC/MS) and not human reader consensus, there was no need for an adjudication method.
5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study
No, a Multi-Reader Multi-Case (MRMC) comparative effectiveness study was not performed. This device is an in vitro diagnostic (IVD) assay designed for quantitative and semi-quantitative determination of a biomarker in urine, not for human interpretation of images or other subjective data. Therefore, the concept of "human readers improving with AI vs. without AI assistance" is not relevant to this type of device.
6. Standalone (Algorithm Only Without Human-in-the Loop Performance) Study
Yes, the performance studies described (accuracy, precision, sensitivity, specificity) represent standalone performance of the assay. The device itself performs the measurement and provides a result; there is no human interpretation component in the direct operation of the assay. The "aid in the detection" statement in the intended use implies a clinician will interpret the result in the broader clinical context, but the assay's performance itself is standalone.
7. Type of Ground Truth Used
- Accuracy Study: Reference laboratory method (GC/MS).
- Other Studies: The ground truth for precision, sensitivity, and specificity studies would typically be established by preparing samples with known concentrations of cotinine or interfering substances, which are then run on the device.
8. Sample Size for the Training Set
No training set information is provided. This device is a homogeneous enzyme immunoassay kit, not a machine learning or AI-based diagnostic that would typically involve a "training set" in the computational sense. Its performance is based on biochemical reactions.
9. How the Ground Truth for the Training Set Was Established
Not applicable, as there is no mention of a "training set" in the context of this traditional immunoassay.
§ 862.3220 Carbon monoxide test system.
(a)
Identification. A carbon monoxide test system is a device intended to measure carbon monoxide or carboxyhemoglobin (carbon monoxide bound to the hemoglobin in the blood) in blood. Measurements obtained by this device are used in the diagnosis and treatment of or confirmation of carbon monoxide poisoning.(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 the limitations in § 862.9.