(167 days)
IMMULITE® Methamphetamine is a solid-phase, chemiluminescent enzyme immunoassay for use with the IMMULITE Automated Analyzer and designed for the qualitative measurement of methamphetamine in urine. It is intended strictly for in vitro diagnostic use in clinical laboratories, in the context of a program involving an established confirmatory test for methamphetamine. A cutoff of 500 ng/mL is used by the IMMULITE Methamphetamine assay to identify positive and negative results.
IMMULITE® Methamphetamine is a solid-phase, chemiluminescent enzyme immunoassay for use with the IMMULITE® Automated Analyzer.
Here's an analysis of the provided text regarding the IMMULITE® Methamphetamine device's acceptance criteria and study details:
1. Table of Acceptance Criteria and Reported Device Performance
The document does not explicitly state pre-defined acceptance criteria for the IMMULITE® Methamphetamine assay. Instead, it presents the results of two comparison studies, implicitly suggesting that these results were deemed acceptable for substantial equivalence. The predicate device's performance (DPC's Coat-A-Count Methamphetamine, K885071) would likely serve as the benchmark for implicit acceptance.
However, based on the provided data, we can infer the reported performance:
| Performance Metric | Against Predicate Device (Coat-A-Count) | Against Gold Standard (GC/MS) |
|---|---|---|
| Relative Sensitivity | 92% | 88% |
| Relative Specificity | 100% | 86% |
| Agreement | 97% | 87% |
2. Sample Sizes Used for the Test Set and Data Provenance
-
Against Predicate Device (Coat-A-Count):
- Sample Size: 214 urine samples.
- Data Provenance: Samples were from "volunteer donors, presumed not to be drug abusers, and a reference lab." This suggests a mix of potentially healthy individuals and samples from a laboratory setting. The country of origin is not specified, but the manufacturer is based in Los Angeles, CA, USA, making it highly probable the data is from the USA.
- Retrospective/Prospective: Not explicitly stated, but the description "urine samples from volunteer donors... and a reference lab" sounds like it could be a collection of existing samples (retrospective) or newly collected for the study (prospective). Without further detail, it's difficult to definitively classify.
-
Against Gold Standard (GC/MS):
- Sample Size: 37 urine samples.
- Data Provenance: Samples were "obtained similarly as above," implying the same mix of volunteer donors and reference lab samples, likely from the USA.
- Retrospective/Prospective: Similar to the above, not explicitly stated.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts
The document does not mention the use of experts to establish ground truth for either comparison study.
- For the comparison with the predicate device, the "ground truth" was established by the predicate device itself (Coat-A-Count Methamphetamine).
- For the comparison with GC/MS, the "ground truth" was established by GC/MS (Gas Chromatography/Mass Spectrometry), which is a highly accurate analytical method for drug detection. This method itself acts as the expert/definitive truth in this context, not human experts interpreting data.
4. Adjudication Method for the Test Set
Not applicable. There was no mention of human expert review or adjudication in either study for establishing ground truth. The comparisons were made directly to the results obtained from the predicate device or the GC/MS analysis.
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done
No, a Multi-Reader Multi-Case (MRMC) comparative effectiveness study was not done. This device is an in vitro diagnostic (IVD) assay designed to provide a quantitative measurement (which is then interpreted qualitatively based on a cutoff), not an imaging or diagnostic AI requiring human interpretation. Therefore, a study comparing human readers with and without AI assistance is not relevant to this type of device.
6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) Was Done
Yes, the studies reported are essentially standalone performance studies for the IMMULITE® Methamphetamine assay. The device itself generates a result (counts per second, which is then compared to a 500 ng/mL cutoff) without human intervention in the result generation process. The comparisons are between the device's output and the output of a predicate device or a gold standard method.
7. The Type of Ground Truth Used
- Against Predicate Device: The ground truth was the predicate device's measurement (Coat-A-Count Methamphetamine).
- Against GC/MS: The ground truth was the GC/MS result, which is considered an objective and highly accurate analytical method, often serving as a gold standard in toxicology.
8. The Sample Size for the Training Set
The document does not report any sample sizes for a training set. This is generally expected for IVD assays like this, where the "training" involves developing the assay's chemical reagents and protocols to achieve desired performance characteristics. There isn't an explicit "algorithm" that is trained on a dataset in the same way as an AI/ML model for image analysis, for example. The performance characteristics are intrinsic to the assay chemistry and mechanics.
9. How the Ground Truth for the Training Set Was Established
Since no training set is described or implied for a machine learning algorithm, this question is not applicable in the context of this traditional IVD device. The "ground truth" in the development of such assays typically refers to the known concentrations of analytes in calibrators and controls used during the assay's design and optimization phase, and ultimately validated against reference methods like GC/MS.
§ 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).