(188 days)
The Amphetamine/Methamphetamine assay is used for the qualitative analysis of amphetamine/methamphetamine in human urine with a cutoff of 1,000 ng/mL for use in clinical laboratories. Measurements obtained by this device are used in the diagnosis and treatment of amphetamine/methamphetamine use or overdose.
The Amphetamine/Methamphetamine assay is calibrated with d-methamphetamine and will detect a variety of amphetamines and their metabolites.
The Amphetamine/Methamphetamine assay provides only a preliminary analytical test result. A more specific alternate chemical method must be used in order to obtain a confirmed analytical result. Gas chromatography/mass spectrometry (GC/MS) is the preferred confirmatory method. Clinical consideration and professional judgment should be applied to any drug of abuse test result, particularly when preliminary positive results are used.
Amphetamine/Methamphetamine is an in vitro diagnostic assay for the qualitative analysis of amphetamine/methamphetamine in human urine. The assay is a homogeneous enzyme immunoassay with a 1,000 ng/mL cutoff. The assay is based on competition between drug in the specimen and drug labeled with the enzyme glucose-6-phosphate dehydrogenase (G6PDH) for antibody binding sites. Enzyme activity decreases upon binding to the antibody, so the drug concentration in the specimen can be measured in terms of enzyme activity.
The Abbott Laboratories Amphetamine/Methamphetamine assay is a qualitative in vitro diagnostic assay used for the detection of amphetamine/methamphetamine in human urine.
Here's an analysis of its acceptance criteria and the study that proves it meets them:
1. Acceptance Criteria and Reported Device Performance:
The primary acceptance criterion for this device is substantial equivalence to a legally marketed predicate device. The study explicitly states the goal of demonstrating similar performance characteristics.
| Acceptance Criteria Category | Specific Criteria | Reported Device Performance | Comments |
|---|---|---|---|
| Substantial Equivalence (Predicate Device) | Agreement with Emit® II Monoclonal Amphetamine/Methamphetamine assay (K920507) | 100% agreement (concordance) | This is the primary claim for substantial equivalence. |
| Substantial Equivalence (Confirmatory Method) | Acceptable correlation with GC/MS | 81% agreement (concordance) | While 100% was achieved against the predicate assay, the agreement with GC/MS is lower at 81%, indicating some discrepancies. |
| Qualitative Analysis Cutoff | 1,000 ng/mL | 1,000 ng/mL | The device operates at the specified cutoff. |
| Limit of Detection (Sensitivity) | Not explicitly stated as an acceptance criterion for comparison, but reported. | 500 ng/mL | This indicates the lowest concentration the device can reliably detect. |
| Precision | Not explicitly stated as an acceptance criterion for comparison, but reported. | Total %CV: Verifier I (0.42%), Cutoff Calibrator (0.40%), Verifier II (0.39%), -25% Control of Cutoff Calibrator (0.44%), +25% Control of Cutoff Calibrator (0.41%) | Very low %CV values indicate high precision (reproducibility) of the assay. |
2. Sample Size Used for the Test Set and Data Provenance:
- Test Set Size: The document does not explicitly state the total number of clinical specimens used for the comparative performance studies. It mentions that "The clinical specimens tested ranged from 826 to 1,994 ng/mL," which suggests a range of concentrations rather than a sample size. However, given the context of concordance tables, it can be inferred that a set of clinical specimens was used to compare the new assay against the predicate and GC/MS. The number of samples for each comparison is not provided.
- Data Provenance: Not specified in the provided text (e.g., country of origin, retrospective or prospective).
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts:
- Number of Experts: Not applicable, as the ground truth was established by either a predicate device or a confirmatory chemical method (GC/MS), not by human expert interpretation.
- Qualifications of Experts: Not applicable.
4. Adjudication Method for the Test Set:
- Adjudication Method: Not applicable. The comparisons were made directly to the predicate device's results and GC/MS results. There's no mention of a human adjudication process to resolve discrepancies.
5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study:
- MRMC Study: No, there is no mention of a multi-reader multi-case (MRMC) comparative effectiveness study. This device is an in vitro diagnostic assay, meaning its performance is assessed against analytical methods rather than human reader interpretation. Therefore, quantifying improvement with AI vs. without AI assistance is not relevant in this context.
6. Standalone (Algorithm Only Without Human-in-the-Loop Performance) Study:
- Standalone Study: Yes, the performance characteristics described (concordance, precision, limit of detection) represent the standalone performance of the Amphetamine/Methamphetamine assay (algorithm only). It does not involve a human in the loop for interpretation of the assay's direct output. The subsequent step for a preliminary positive result is confirmation by GC/MS, rather than human interpretation of the initial assay result.
7. Type of Ground Truth Used:
- Type of Ground Truth:
- Predicate Device Results: For the primary substantial equivalence claim, the results from the Emit® II Monoclonal Amphetamine/Methamphetamine assay (K920507) were used as a comparative ground truth.
- Confirmatory Method: For additional correlation, Gas Chromatography/Mass Spectrometry (GC/MS) was used as a superior analytical chemical method, considered the "preferred confirmatory method" and thus a more definitive ground truth.
8. Sample Size for the Training Set:
- The document does not provide information on the sample size for a training set. As this is a traditional immunoassay, it likely does not involve machine learning or AI models that require explicit training sets in the same way. The assay's performance is driven by its biochemical reagents and protocol.
9. How the Ground Truth for the Training Set Was Established:
- As there is no mention of a training set or a machine learning component, this information is not applicable. The assay's "training" would be through its development and optimization process in the lab, which is not detailed here.
§ 862.3610 Methamphetamine test system.
(a)
Identification. A methamphetamine test system is a device intended to measure methamphetamine, a central nervous system stimulating drug, in serum, plasma, and urine. Measurements obtained by this device are used in the diagnosis and treatment of methamphetamine use or overdose.(b)
Classification. Class II (special controls). A methamphetamine test system is not exempt if it is intended for any use other than employment or insurance testing or is intended for Federal drug testing programs. 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, provided the test system is intended for employment and insurance testing and includes a statement in the labeling that the device is intended solely for use in employment and insurance testing, and does not include devices intended for Federal drug testing programs (e.g., programs run by the Substance Abuse and Mental Health Services Administration (SAMHSA), the Department of Transportation (DOT), and the U.S. military).