(145 days)
The LZI Amphetamines 500 Enzyme Immunoassay is intended for the qualitative and semi-quantitative determination of amphetamine and methamphetamine in human urine, at a cutoff value of 500 ng/mL when calibrated with d-methamphetamine. The assay is designed for professional use with a number of automated clinical chemistry analyzers.
The LZI Amphetamines 500 Drugs of Abuse (DAU) Calibrators are for use as calibrators in the qualitative and semi-quantitative calibration of the LZI Amphetamines Enzyme Immunoassay.
The LZI Amphetamines 500 Drugs of Abuse (DAU) Controls are for use as assayed quality control materials to monitor the precision of the LZI Amphetamines 500 Enzyme Immunoassay.
The assay provides only a preliminary analytical 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) is the preferred confirmatory method). Clinical consideration and professional judgment should be exercised with any drug of abuse test result, particularly when the preliminary test result is positive.
The LZI Amphetamines 500 assay is a homogeneous enzyme immunoassay with readyto-use liguid reagent. The assay is based on competition between drug in the sample and drug labeled with the enzyme glucose-6-phosphate dehydrogenase (G6PDH) for a fixed amount of antibody in the reagent. Enzyme activity decreases upon binding to the antibody, and the drug concentration in the sample is measured in terms of enzyme activity. In the absence of drug in the sample, amphetamines-labeled G6PDH conjugate is bound to antibody, and the enzyme activity is inhibited. On the other hand, when free drug is present in the sample, antibody would bind to free drug, the unbound amphetamines-labeled G6PDH then exhibits its maximal enzyme activity. Active enzyme converts nicotinamide adenine dinucleotide (NAD) to NADH, resulting in an absorbance change that can be measured spectrophotometrically at 340 nm.
The LZI Amphetamines 500 Enzyme Immunoassay is a kit comprised of two reagents, an R1 and R2 which are bottled separately but sold together within the kit.
The Ri solution contains two mouse monoclonal anti-amphetamines antibodies, glucose-6-phosphate (G6P) nicotinamide adenine dinucleotide (NAD), stabilizers, and sodium azide (0.09%) as a preservative. The R2 solution contains glucose-6-phosphate dehydrogenase (G6PDH) labeled with amphetamines in buffer with sodium azide (0.09%) as preservative.
The LZI Amphetamines 500 Enzyme Immunoassay calibrators and controls contain 0, 250, 375, 500, 625, 1000, or 2000 ng/mL of d-methamphetamine in human urine with sodium azide (0.09%) as preservative. These five calibrators and two controls are sold as individual bottles.
Acceptance Criteria and Device Performance for LZI Amphetamines 500 Enzyme Immunoassay
This document outlines the acceptance criteria and reported device performance for the LZI Amphetamines 500 Enzyme Immunoassay, based on the provided 510(k) summary.
1. Table of Acceptance Criteria and Reported Device Performance
The provided document details various performance characteristics, primarily precision and method comparison (agreement with GC/MS). The acceptance criteria are not explicitly stated as "acceptance criteria" but are implied by the reported performance, with the device demonstrating high agreement rates with confirmatory methods for positive and negative samples, and good precision metrics.
Implicit Acceptance Criteria (based on reported performance for a device seeking substantial equivalence):
- High agreement (e.g., 96-100%) with a confirmatory method (GC/MS) for both positive and negative clinical samples.
- Reliable qualitative determination (positive/negative) around the 500 ng/mL cutoff, with minimal misclassification at concentrations significantly above or below the cutoff.
- Acceptable precision (low coefficient of variation (CV%) and standard deviation (SD)) for semi-quantitative measurements across various concentrations, indicating consistent results within and between runs.
Table 1: Device Performance Summary for LZI Amphetamines 500 Enzyme Immunoassay
| Performance Metric | Acceptance Criteria (Implicit) | Reported Device Performance (d-methamphetamine) | Reported Device Performance (d-amphetamine) |
|---|---|---|---|
| Method Comparison (Clinical Samples) - 500 ng/mL Cutoff | |||
| Agreement with Positive Samples (Semi-Quantitative) | High agreement (e.g., ≥95% agreement) with confirmatory method (GC/MS) | 100% agreement | 97.8% agreement |
| Agreement with Negative Samples (Semi-Quantitative) | High agreement (e.g., ≥95% agreement) with confirmatory method (GC/MS) | 67.4% agreement (This value is lower than ideal but likely considered acceptable in the context of screening tests where confirmation is required. It suggests some samples below the cutoff might be reported as positive by EIA, indicating a need for GC/MS confirmation as stated in the intended use.) | 100% agreement |
| Agreement with Positive Samples (Qualitative) | High agreement (e.g., ≥95% agreement) with confirmatory method (GC/MS) | 100% agreement | 96.4% agreement |
| Agreement with Negative Samples (Qualitative) | High agreement (e.g., ≥95% agreement) with confirmatory method (GC/MS) | 69.8% agreement (Similar considerations as above for semi-quantitative negative samples.) | 100% agreement |
| Precision (Qualitative Results at 500 ng/mL Cutoff) | |||
| Samples at +25% to +100% of Cutoff (>625 ng/mL) | Consistent positive results (e.g., 100% positive) | 100% Positive (Across all tested concentrations for Total Precision) | 100% Positive (Across all tested concentrations for Total Precision) |
| Samples at -100% to -25% of Cutoff ( |
§ 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).