(55 days)
The DRI Benzodiazepine Assay is a homogeneous enzyme immunoassay intended for the qualitative and/or semi-quantitative determination of the presence of benzodiazepines and their metabolites in human urine at a cutoff concentration of 200 ng/mL. The assay is intended to be used in laboratories a simple and rapid analytical screening procedure to detect benzodiazepines in human urine. The assay is designed for use with a number of clinical chemistry analyzers. This assay is calibrated against Oxazepam. This product is intended to be used by trained professionals only.
The semi-quantitative mode is for the purpose of enabling laboratories to determine an appropriate dilution of the specimen for confirmation by a confirmatory method such as Liquid Chromatography/tandem mass spectrometry (LC-MS/MS) or permitting laboratories to establish quality control procedures.
The assay provides only a preliminary analytical test result. A more specific alternative chemical must be used to obtain a confirmed analytical result. Gas chromatography/ mass spectrometry (GC/MS) or Liquid chromatography/tandem mass spectrometry (LC-MS/MS) is the preferred confirmatory method.
Clinical and professional judgment should be applied to any drug of abuse test result, particularly when preliminary results are used. For In Vitro Diagnostic Use Only.
The DRI Benzodiazepine Assay is a homogeneous enzyme immunoassay with liquid ready-to-use reagents. The assay uses a specific antibody which can detect most benzodiazepines and their metabolites in urine. The assay is based on the competition of an enzyme glucose- 6-phosphate dehydrogenase (G6PDH) labeled drug and the drug from the urine sample for a fixed amount of specific antibody binding sites. In the absence of free drug from the sample, the enzyme-labeled drug is bound by the specific antibody and the enzyme activity is inhibited. This phenomenon creates a relationship between drug concentration in urine and the enzyme activity. The enzyme G6PDH activity is determined spectrophotometrically at 340 nm by measuring its ability to convert nicotinamide adenine dinucleotide (NAD) to NADH.
The assay consists of reagents A and E.
Reagent A: Contains sheep polyclonal anti-benzodiazepine antibodies, glucose-6-phosphate (G6P) and nicotinamide adenine dinucleotide (NAD) in Tris buffer with sodium azide as a preservative.
Reagent E: Contains benzodiazepine derivative labeled with glucose-6-phosphate dehydrogenase (G6PDH) in Tris buffer with sodium azide as a preservative.
The provided document describes the analytical performance verification of the DRI Benzodiazepine Assay, an in vitro diagnostic device, and not an AI/ML-enabled medical device. Therefore, many of the requested categories (e.g., number of experts, adjudication methods, MRMC studies, standalone performance of an algorithm, training set details) are not applicable to this type of device and study.
However, I can extract the acceptance criteria and reported performance for the analytical studies conducted, which demonstrate the device's substantial equivalence to a predicate device.
Device Name: DRI Benzodiazepine Assay
Regulation Number: 21 CFR 862.3170
Regulation Name: Benzodiazepine test system
Regulatory Class: Class II
Product Code: JXM
1. Table of Acceptance Criteria and Reported Device Performance
The document does not explicitly state "acceptance criteria" in a tabulated format for each study, but rather presents the results of various analytical performance studies which are implicitly used to demonstrate the device's suitability and substantial equivalence. I will infer the acceptance criteria from typical requirements for such in vitro diagnostic assays and the presented results.
| Study Parameter | Implied Acceptance Criterion (Typical for IVD) | Reported Device Performance |
|---|---|---|
| Precision (Qualitative) | All replicates at ±25%, ±50%, ±75%, ±100% of cutoff show consistent classification; some variability expected at cutoff (200 ng/mL). | At -100% (0 ng/mL), -75% (50 ng/mL), -50% (100 ng/mL), -25% (150 ng/mL): 80/80 (100%) Negative. |
| At +25% (250 ng/mL), +50% (300 ng/mL), +75% (350 ng/mL), +100% (400 ng/mL): 80/80 (100%) Positive. | ||
| At 100% cutoff (200 ng/mL): 16/64 (20%/80%) Negative/Positive. | ||
| Precision (Semi-Quantitative) | Similar to qualitative, with expected distribution around cutoff. | At -100% (0 ng/mL), -75% (50 ng/mL), -50% (100 ng/mL), -25% (150 ng/mL): 80/80 (100%) Negative. |
| At +25% (250 ng/mL), +50% (300 ng/mL), +75% (350 ng/mL), +100% (400 ng/mL): 80/80 (100%) Positive. | ||
| At 100% cutoff (200 ng/mL): 27/53 (33.75%/66.25%) Negative/Positive. | ||
| Spike Recovery (Qualitative) | Accurate classification of samples below/above cutoff. | 150 ng/mL (Below Cutoff): 20/20 (100%) Negative. |
| 250 ng/mL (Above Cutoff): 20/20 (100%) Positive. | ||
| Analytical Recovery and Linearity | Recoveries within a generally accepted range (e.g., 80-120%) across the tested range. Implies accuracy and proportionality to concentration. | Recovery between 98.1% and 113.8% for Oxazepam concentrations ranging from 100 ng/mL to 1000 ng/mL. (Level 1, 0 ng/mL, N/A recovery). |
| Method Comparison and Accuracy (Qualitative) | High overall agreement with confirmatory method (LC-MS/MS), particularly for positive and negative agreement. | Overall agreement with LC-MS/MS: 96.2% (102/106 samples). |
| Negative agreement: 92.9% (52/56). | ||
| Positive agreement: 100% (50/50). | ||
| Four discordant samples identified as positive by the device but below cutoff by LC-MS/MS were due to significant levels of benzodiazepine metabolites not quantified by the parent compound concentration in LC-MS/MS, which the immunoassay cross-reacts with. This is expected behavior for an immunoassay designed to detect metabolites. | ||
| Method Comparison and Accuracy (Semi-Quantitative) | High overall agreement with confirmatory method (LC-MS/MS), similar to qualitative. | Overall agreement with LC-MS/MS: 96.2% (102/106 samples). |
| Negative agreement: 92.9% (52/56). | ||
| Positive agreement: 100% (50/50). | ||
| Same four discordant samples as qualitative, explained by metabolite cross-reactivity. | ||
| Specificity (Cross-reactivity with structurally related compounds) | Detection of various benzodiazepine compounds and their metabolites at specified concentrations. | Many compounds showed excellent cross-reactivity (e.g., α-Hydroxyalprazolam, Alprazolam, Estazolam, Diazepam, Flunitrazepam, Nordiazepam, Oxazepam) with cross-reactivity >90% (e.g., 91-200%). |
| Some showed lower but acceptable cross-reactivity (e.g., 7-Aminoclonazepam: 8%; Chlordiazepoxide: 29%; Lorazepam: 29%). | ||
| Glucuronides conjugate forms typically show very low cross-reactivity ( |
§ 862.3170 Benzodiazepine test system.
(a)
Identification. A benzodiazepine test system is a device intended to measure any of the benzodiazepine compounds, sedative and hypnotic drugs, in blood, plasma, and urine. The benzodiazepine compounds include chlordiazepoxide, diazepam, oxazepam, chlorzepate, flurazepam, and nitrazepam. Measurements obtained by this device are used in the diagnosis and treatment of benzodiazepine use or overdose and in monitoring levels of benzodiazepines to ensure appropriate therapy.(b)
Classification. Class II (special controls). A benzodiazepine 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).