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The DRI Ecstasy Enzyme Immunoassay is a homogeneous enzyme immunoassay intended for the qualitative or semiquantitative determination of ecstasy drugs in human urine. The assay provides a simple and rapid analytical screening procedure for detecting ecstasy drugs at a Cutoff level of 500 ng/mL.

This assay provides only a preliminary analytical test result. A more specific alternate chemical method must be used in order to obtain a confirmed analytical result. Gas chromatography/mass spectrometry (GC/MS) is the preferred confirmatory method. Clinical consideration and professional judgment should be applied to any drug of abuse test result, particularly when preliminary positive results are used.

The DRI Ecstasy Assay is a liquid ready-to-use homogeneous enzyme immunoassay. The assay uses specific antibodies, which can detect ecstasy drugs in urine with minimal cross-reactivity to various amphetamine compounds. The assay is based on competition between a drug labeled with glucose-6-phosphate dehydrogenase (G6PDH) enzyme, and free drug from the urine sample for a fixed amount of specific antibody binding sites. In the absence of free drug from the sample, the specific antibody binds the drug labeled with G6PDH causing a decrease in enzyme activity. This phenomenon creates a direct relationship between drug concentration in urine and enzyme activity. The enzyme G6PDH activity is determined spectrophotometrically at 340 nm by measuring its ability to convert nicotinamide adenine dinucleotide (NAD) to NADH.

Here's a breakdown of the acceptance criteria and study information for the DRI® Ecstasy Enzyme Immunoassay, based on the provided text:

1. Acceptance Criteria and Reported Device Performance

The document does not explicitly state "acceptance criteria" as a set of predefined thresholds that the device must meet to be approved. Instead, it presents the performance characteristics of the device without directly comparing them to a pre-stated pass/fail benchmark within the document. However, we can infer the reported performance that was deemed acceptable for substantial equivalence.

Comparison to Predicate Device (CEDIA DAU Amphetamines/Ecstasy Assay):

2. Sample Size Used for the Test Set and Data Provenance

The document provides limited detail on specific sample sizes for all tests.

• Accuracy Test Set:
  • New Device: 92 true positives, 18 true negatives. This indicates a total of 110 samples were used in the accuracy study for the DRI Ecstasy Enzyme Immunoassay.
  • Predicate Device (for comparison): 159 true positives, 18 true negatives. This indicates a total of 177 samples were used in the accuracy study for the predicate device.
• Other tests (sensitivity, linearity, specificity, precision): The specific sample sizes are not explicitly stated.
• Data Provenance: The document does not specify the country of origin of the data or whether the studies were retrospective or prospective. It refers to them as "traditional laboratory studies."

3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications

• The ground truth for the test set was established using Gas Chromatography/Mass Spectrometry (GC/MS).
• The document does not mention the use of human experts or their qualifications for establishing the ground truth; GC/MS is described as the "preferred confirmatory method" and the reference standard.

4. Adjudication Method

• Since the ground truth was established by GC/MS (a definitive laboratory method), there was no mention of an adjudication method involving human readers for the test set. The GC/MS results served as the objective reference.

5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study

• No, a multi-reader multi-case (MRMC) comparative effectiveness study was not performed or reported in this document. This device is an in-vitro diagnostic assay, not an imaging or diagnostic AI tool that would typically involve human readers interpreting results with or without AI assistance.

6. Standalone (Algorithm Only Without Human-in-the-Loop Performance) Study

• Yes, the performance data presented (sensitivity, precision, linearity, accuracy, specificity) represents the standalone performance of the DRI Ecstasy Enzyme Immunoassay itself. It evaluates the assay's ability to detect ecstasy drugs in urine based on its chemical reactions and spectrophotometric measurements, without human interpretation other than reading the instrument's output. The document explicitly states that the assay "provides only a preliminary analytical test result" and "a more specific alternate chemical method must be used in order to obtain a confirmed analytical result" (GC/MS). This reinforces that the assay's performance is being assessed as an initial screening tool, independent of human interpretive steps for confirmation.

7. Type of Ground Truth Used

• The type of ground truth used was GC/MS (Gas Chromatography/Mass Spectrometry), which is a highly reliable and definitive analytical method for confirming the presence and concentration of substances like drugs.

8. Sample Size for the Training Set

• The document does not provide any information about a "training set" or its sample size. This is typical for traditional enzyme immunoassays, where the assay itself is developed and optimized through chemical and biochemical engineering, rather than machine learning models that require distinct training sets.

9. How the Ground Truth for the Training Set Was Established

• As no training set is mentioned for this type of device, no information is provided on how its ground truth would have been established. The device development process would have involved internal validation and optimization against known standards and samples, but these are not referred to as a "training set" in the context of this submission.

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