(65 days)
The Emit® II Plus Ecstasy Assay is a homogeneous enzyme immunoassay with a 300 ng/mL or 500 ng/mL cutoff. The assay is intended for use in laboratories for the qualitative and/or semiquantitative analysis of methylenedioxymethamphetamine (MDMA) and closely related drugs in human urine. Emit® II Plus Assays are designed for use with a number of chemistry analyzers.
The Emit® II Plus Ecstasy Assay provides only a preliminary analytical test result. A more specific alternative chemical method must be used to obtain a confirmed analytical result. Gas chromatography/mass spectrometry (GC/MS) is the preferred confirmatory method. Other chemical confirmation methods are available. Clinical consideration and professional judgment should be applied to any drug-of-abuse test result, particularly when preliminary positive results are used.
The Emit® II Plus Ecstasy Calibrators / Controls are used in the calibration of the Emit® II Plus Ecstasy Assay. These standards may also be used as quality control materials based upon the Ecstasy assay cutoff.
Assay: The Emit® II Plus Ecstasy Assay is a homogeneous enzyme immunoassay used for the analysis of specific compounds in human urine. The assay is based on competition between drug in the specimen and drug labeled with recombinant ofucose-6-phosphate dehydrogenase (rG6PDH) 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. Active enzyme converts nicotinamide adenine dinucleotide (NAD) to NADH in the presence of glucose-6-phosphate (G6P), resulting in an absorbance change that is measured spectrophotometrically. Endogenous serum G6PDH does not interfere because the coenzyme NAD functions only with the bacterial (Leuconostoc mesenteroides) enzyme employed in the assay.
Calibrator / Control: The Emit® II Plus Ecstasy Calibrators / Controls are liquid, four-level calibrators prepared from MDMA, urine and preservatives.
Acceptance Criteria and Device Performance for Emit® II Plus Ecstasy Assay
1. Table of Acceptance Criteria and Reported Device Performance
The acceptance criteria for substantial equivalence are not explicitly stated as numerical targets in the provided document. Instead, the demonstration of substantial equivalence relies on a comparison to a legally marketed predicate device (Microgenics DRI® Ecstasy Enzyme Immunoassay, K012110) in terms of intended use, methodology, and performance characteristics.
The study presented focuses on demonstrating qualitative agreement with a reference method (GC/MS) at two different cutoff concentrations. While no specific "acceptance criteria" tables are given for overall performance, the study implicitly aims to show high agreement.
For the purpose of this response, "Acceptance Criteria" will be extrapolated from the observed performance and the overall goal of demonstrating a high level of agreement with the reference method.
| Performance Metric | Acceptance Criteria (Implicit) | Reported Device Performance (300 ng/mL Cutoff) | Reported Device Performance (500 ng/mL Cutoff) |
|---|---|---|---|
| Qualitative Agreement with GC/MS | High percentage agreement | 98% (98/100) | 96% (96/100) |
| False Negative Rate (samples positive by GC/MS but negative by Assay) | Low | 2/57 (3.5%) | 4/57 (7.0%) |
| False Positive Rate (samples negative by GC/MS but positive by Assay) | 0 (desired) | 0/43 (0%) | 0/43 (0%) |
2. Sample Size and Data Provenance for the Test Set
- Sample Size:
- For the 300 ng/mL cutoff study: 100 urine specimens.
- For the 500 ng/mL cutoff study: 100 urine specimens.
- Data Provenance: The document does not explicitly state the country of origin of the data. The study is retrospective, as it involves testing collected urine specimens and comparing results to a previously established reference method (GC/MS).
3. Number of Experts and Qualifications for Ground Truth
The ground truth was established by Gas Chromatography/Mass Spectrometry (GC/MS). The document does not specify the number of experts or their qualifications for performing and interpreting the GC/MS results. GC/MS is a laboratory analytical method, and its interpretation would typically be performed by trained laboratory personnel or chemists specializing in toxicology, rather than clinical experts like radiologists.
4. Adjudication Method for the Test Set
No explicit adjudication method is described for the test set. The comparison is directly between the Emit® II Plus Ecstasy Assay results and the GC/MS reference results. Discrepancies are noted and analyzed (e.g., that discrepant samples were within ±50% of the cutoff concentration), but there isn't a stated adjudication process involving multiple human reviewers.
5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study
No. The study described is a comparison of a single device's performance against a reference method (GC/MS) for detecting MDMA in urine. It does not involve human readers or assess the effectiveness of human readers with or without AI assistance. Therefore, there is no effect size reported for human readers improving with AI.
6. Standalone (Algorithm Only) Performance Study
Yes, the study primarily evaluates the standalone performance of the Emit® II Plus Ecstasy Assay. It directly compares the assay's output to the GC/MS reference method without any human intervention or interpretation of the assay results themselves (beyond reading the instrument output).
7. Type of Ground Truth Used
The type of ground truth used is objective analytical data from a reference chemical method: Gas Chromatography/Mass Spectrometry (GC/MS). GC/MS is considered the "gold standard" for confirming drug presence and concentration in toxicology.
8. Sample Size for the Training Set
The document does not specify a separate "training set" size. The information provided relates to the performance evaluation of the Emit® II Plus Ecstasy Assay, implying it is a finished product being evaluated, not a model undergoing active training. Therefore, sample size for a training set is not applicable to the presented data.
9. How the Ground Truth for the Training Set Was Established
Since no training set is described, the method for establishing its ground truth is not applicable to this document.
§ 862.3100 Amphetamine test system.
(a)
Identification. An amphetamine test system is a device intended to measure amphetamine, a central nervous system stimulating drug, in plasma and urine. Measurements obtained by this device are used in the diagnosis and treatment of amphetamine use or overdose and in monitoring levels of amphetamine to ensure appropriate therapy.(b)
Classification. Class II (special controls). An amphetamine 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).