(192 days)
The STC Methamphetamine Intercept™ MICRO-PLATE EIA is intended for use in the qualitative determination of methamphetamine in oral fluid collected with the Intercept™ Drugs of Abuse (DOA) Oral Specimen Collection Device. For In Vitro Diagnostic Use.
The STC Methamphetamine Intercept™ MICRO-PLATE EIA is a competitive micro-plate immunoassay for the detection of methamphetamine in oral fluid collected with the Intercept™ DOA Oral Specimen Collection Device. Specimen or standard is added to an EIA well in combination with an enzyme-labeled hapten derivative. In an EIA well containing an oral fluid specimen positive for methamphetamine, there is a competition between the drug and the enzyme-labeled hapten to bind the antibody fixed onto the EIA wells are then washed, substrate is added, and color is produced. The absorbance measured for each well at 450 mm is inversely proportional to the amount of methamphetamine present in the specimen or calibrator/control.
Here's a breakdown of the acceptance criteria and the study details for the STC Methamphetamine Intercept™ MICRO-PLATE EIA, based on the provided text:
Acceptance Criteria and Device Performance
| Acceptance Criteria Category | Specific Criteria/Metric | Reported Device Performance (STC Methamphetamine Intercept™ MICRO-PLATE EIA) |
|---|---|---|
| Analytical Sensitivity/Limit of Detection (LOD) | LOD (ng/mL) | 8.0 ng/mL |
| Precision | Intra-Assay %CV Range | 6.2 - 7.8% |
| Inter-Assay %CV Range | 7.5 - 8.4% | |
| Analytical Specificity/Cross-Reactivity | % Cross-Reactivity for d-Methamphetamine | 100% (used as kit standard) |
| % Cross-Reactivity for MDMA (Ecstasy) | 288.471% (at 12.5 ng/mL spiked concentration) | |
| Absence of signal for a defined list of common substances (e.g., Acetylsalicylic Acid, Cocaine, Ibuprofen, Morphine) at 10,000 µg/mL | None of the tested compounds produced a signal less than or equal to the Oral Fluid Cutoff Calibrator. | |
| Clinical Performance (Agreement with GC/MS) | % Agreement with Oral Fluid GC/MS for positive and negative samples | 98% agreement (24 positive, 25 negative, 0 false positive, 1 false negative) |
| Clinical Performance (Agreement with Urine Assay) | % Agreement with Urine Assay (EIA and GC/MS) for positive and negative samples | 94% agreement (20 positive, 54 negative, 3 false positive, 2 false negative) |
| Sample pH Effect | No false positives at specific pH ranges | False positives at pH ≤ 6.0 |
| Effect of Common Materials | Identified interfering substances | Orange Juice (pH effect), Cough Syrup (Pseudoephedrine), Antiseptic (pH effect) |
Study Information
2. Sample Size and Data Provenance for the Test Set:
* Sample Size: A total of 80 matching oral fluid and urine specimens were collected. An additional 6 random oral fluid samples were screened and confirmed for methamphetamine.
* Data Provenance: The specimens were collected from "known or suspected drug abusers." The country of origin is not explicitly stated, but given the US FDA regulatory submission, it is likely the study was conducted in the United States. The data appears to be retrospective, as specimens were collected and then tested.
3. Number of Experts and Qualifications for Ground Truth - Test Set:
* The document does not specify the number of experts used to establish the ground truth or their qualifications.
* Ground truth was established by GC/MS (Gas Chromatography/Mass Spectrometry), which is a gold standard analytical method, not by human expert consensus or interpretation of images. Therefore, the concept of "experts" in the context of visual interpretation of results is not directly applicable here for establishing the ground truth of methamphetamine presence. The experts involved would be laboratory personnel skilled in GC/MS operation and data interpretation.
4. Adjudication Method for the Test Set:
* The document does not describe an adjudication method in the traditional sense of resolving discrepancies between human readers. For the clinical performance, samples that tested positive by EIA and 20 samples that tested negative were confirmed by GC/MS. This acts as a confirmation step rather than an adjudication method between multiple interpretations of the device's output.
5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study:
* No, an MRMC comparative effectiveness study was not done. This study focuses on the analytical and clinical performance of the device itself against established methods (GC/MS, predicate urine assay), not on how human readers' performance improves with or without the device's assistance.
6. Standalone Performance Study:
* Yes, a standalone performance study was done. The entire clinical and analytical evaluation describes the performance of the "STC Methamphetamine Intercept™ MICRO-PLATE EIA" as a standalone device. The "clinical data" section directly compares the device's results to GC/MS for oral fluid and a commercial immunoassay/GC/MS for urine samples, demonstrating the algorithm/device's performance without specific human interpretation or intervention in the primary measurement.
7. Type of Ground Truth Used:
* The primary ground truth for both oral fluid and urine samples was established by GC/MS (Gas Chromatography/Mass Spectrometry). This is a highly accurate chemical analytical method, often considered a definitive method for drug detection.
8. Sample Size for the Training Set:
* The document does not explicitly state a training set size or describe a distinct training phase for the device's development. This is typical for immunoassay devices, where the "training" analogous to machine learning models is inherent in the assay design and optimization process (e.g., antibody selection, reagent concentrations, cutoff determination) rather than a separate data-driven training set in the AI sense.
9. How Ground Truth for the Training Set Was Established:
* Since no explicit training set or AI-like "training" is described, the question of how its ground truth was established is not applicable in the context of this document. The assay's performance characteristics (e.g., cutoff) were determined through analytical studies rather than by training on a labeled dataset. The recommended cutoff of 40 ng/mL was explicitly stated to be "within the limit of detection by the STC Methamphetamine Intercept™ MICRO-PLATE EIA," implying it was determined through internal analytical validation.
§ 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).