(38 days)
The Psychemedics Microplate EIA for Amphetamine is an enzyme immunoassay (EIA) for the preliminary qualitative detection of amphetamine in human head and body hair using an amphetamine calibrator at 3 ng /10 mg hair cutoff for the purpose of identifying amphetamine use. This is an in vitro diagnostic device intended exclusively for Psychemedics use only. Psychemedics has not performed an evaluation of reproducibility at different laboratories.
The Psychemedics Microplate EIA amphetamine assay provides only a preliminary analytical test result. A more specific alternative chemical method must be used in order to obtain a confirmed analytical result. Gas or Liquid Chromatography/Mass Spectrometry (GC/MS or LC/MS/MS) is the preferred confirmatory method. Clinical consideration and professional judgment should be exercised with any drug of abuse test result, particularly when the preliminary result is positive.
The test consists of two parts; a pre-analytical hair treatment procedure (to convert the solid matrix of hair to a measurable liquid matrix) and the screening assay, the Psychemedics Microplate EIA for Amphetamine. The screening portion of the test system consists of ( 1 ) microplate wells coated with multiple antigens including methamphetamine conjugated to bovine serum albumin (BSA), monoclonal mouse anti-amphetamine, rabbit anti-mouse secondary antibody conjugated to HRP (horseradish peroxidase), substrate [3, 3', 5, 5' tetramethylbenzidine (TMB)], HCl to acidify (and stop the reaction), and wash buffer for washing the plates. Absorbance in the wells is read with a microplate reader.
Here's a breakdown of the acceptance criteria and the study details for the Psychemedics Microplate EIA for Amphetamine in Hair, based on the provided 510(k) summary:
1. Table of Acceptance Criteria and Reported Device Performance
The document doesn't explicitly state "acceptance criteria" with numerical targets in a structured table for diagnostic accuracy (e.g., sensitivity, specificity). Instead, the performance is demonstrated through various studies. The primary comparison is against LC/MS/MS as the confirmatory method. The closest we get to performance criteria are successful precision, cross-reactivity, interference, and environmental contamination studies, as well as substantial equivalence to the predicate device.
Implicit Acceptance Criteria and Reported Device Performance:
| Performance Aspect | Acceptance Criteria (Implicit from Study Design) | Reported Device Performance |
|---|---|---|
| Precision | Demonstrate consistent results across intra-assay and inter-assay conditions for negative, cutoff, and various concentration levels relative to the cutoff. | Intra-Assay: 15/15 positive or negative results for each level (including -100%, -75%, -50%, -25% for negative; +25%, +50%, +75%, +100% for positive). |
| Inter-Assay: 75/75 positive or negative results for each level (including -100%, -75%, -50%, -25% for negative; +25%, +50%, +75%, +100% for positive). All results were concordant with expected outcomes. | ||
| Comparison to LC/MS/MS (Diagnostic Accuracy) | Demonstrate substantial equivalence to LC/MS/MS for identifying amphetamine use, with minimal discordant results. | Out of 180 samples: |
- True Negatives: 38 (EIA Negative, LC/MS/MS Negative)
- False Positives: 14 (EIA Positive, LC/MS/MS Negative)
- Discordant within Negative Range:
- EIA Positive, LC/MS/MS
§ 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).