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The Ecstasy Enzyme Immunoassay is a homogeneous enzyme immunoassay with a 500 ng/mL cutoff. The assay is intended for use in the qualitative and semi-quantitative analyses of Ecstasy (MDMA) in human urine. The assay is designed for professional use with a number of automated clinical chemistry analyzers.

The Ecstasy Enzyme Immunoassay provides only a preliminary analytical test result. A more specific alternative chemical method must be used to obtain a confirmed analytical result. Gas chromatography/mass spectrometry (GC/MS) is the preferred confirmatory method. Clinical consideration and professional judgement should be applied to any drug-of-abuse test result, particularly when preliminary positive results are used.

The Ecstasy Drug of Abuse Calibrators are intended for in vitro diagnostic use for the calibration of the Ecstasy enzyme immunoassay to detect ecstasy in human urine.

The Ecstasy Drug of Abuse Controls are intended for in vitro diagnostic use for the validation of the Ecstasy enzyme immunoassay to detect ecstasy in human urine.

LZI's Ecstasy Enzyme Immunoassay is a ready-to-use, liquid reagent, homogeneous enzyme immunoassay. The assay uses specific antibody that can detect Ecstasy (MDMA) in human urine with minimal cross-reactivity to various, common prescription drugs and abused drugs. The assay is based on competition between ecstasy labeled with glucose-6-phosphate dehydrogenase (G6PDH) enzyme and free drug from the urine sample for a fixed amount of specific antibody. In the absence of free drug from the urine sample the specific antibody binds to the drug labeled with G6PDH enzyme causing a decrease in enzyme activity. The G6PDH enzyme activity is determined spectrophotometrically at 340 nm by measuring its ability to covert nicotinamide adenine dinucleotide (NAD) to NADH.

All of the Single Analyte Urine DAU Calibrators and Controls are human urine-based liquid, and ready to use. These Calibrators and Controls do not have any especially unique technical characteristics. Each contains a known concentration of a specific drug analyte. The Negative DAU calibrator is a processed, drug-free human urine matrix, which has also been used with all assays. The calibrators and controls are prepared by spiking known concentrations of drug analyte into the Negative DAU Calibrator matrix.

Here's a breakdown of the acceptance criteria and study information for the Lin-Zhi International, Inc. Ecstasy Enzyme Immunoassay, based on the provided text:

Acceptance Criteria and Device Performance

The acceptance criteria are implicitly defined by comparing the performance of the LZI Ecstasy EIA to the performance of the predicate device, DRI Ecstasy Assay, and demonstrating "acceptable results." Specific quantitative acceptance criteria are not explicitly stated in the document as numerical thresholds, but rather through the reported performance relative to the predicate or confirmed methods.

Study Details

1. Sample Size used for the test set and the data provenance:

   • Test Set Sample Size: 127 samples for the Accuracy study (comparison against GC/MS).
   • Data Provenance: Not explicitly stated but clinical performance data typically comes from laboratory testing of human urine samples. The document does not specify country of origin or whether it's retrospective or prospective. Given the nature of a 510(k) for an in vitro diagnostic, these are typically laboratory-based studies.

2. Number of experts used to establish the ground truth for the test set and the qualifications of those experts:

   • Number of experts: Not applicable for this type of device.
   • Qualifications of experts: The ground truth was established by Gas Chromatography/Mass Spectrometry (GC/MS), which is an analytical chemical method, not human expert consensus.

3. Adjudication method (e.g., 2+1, 3+1, none) for the test set:

   • Adjudication Method: Not applicable. The ground truth was established by GC/MS, which is considered a definitive analytical method, not requiring human adjudication for interpretation in this context.

4. If a multi-reader multi-case (MRMC) comparative effectiveness study was done, If so, what was the effect size of how much human readers improve with AI vs without AI assistance:

   • MRMC Study: No. This device is an enzyme immunoassay for drug detection in urine, not an imaging or diagnostic device requiring human reader interpretation in the same way as AI in radiology, for example. The output is a quantitative or qualitative chemical result.

5. If a standalone (i.e. algorithm only without human-in-the loop performance) was done:

   • Standalone Performance: Yes, the performance described (precision, sensitivity, accuracy, analytical recovery, specificity) is "standalone" performance of the assay itself, without human intervention in the result determination beyond instrument operation and result recording. The "human-in-the-loop" aspect for such a device is typically clinical interpretation of the analytically confirmed result, not the initial assay performance.

6. The type of ground truth used (expert consensus, pathology, outcomes data, etc.):

   • Ground Truth Type: GC/MS (Gas Chromatography/Mass Spectrometry). This is a highly specific and sensitive analytical chemical method considered the gold standard for drug confirmation.

7. The sample size for the training set:

   • Training Set Sample Size: Not explicitly mentioned. For an immunoassay, "training" typically refers to the development and optimization of the assay reagents and parameters, which would involve numerous experiments and titrations, rather than a distinct "training set" of patient samples in the way an AI algorithm uses for machine learning. The stability, precision, and accuracy studies would be considered part of the validation/testing after the assay is developed.

8. How the ground truth for the training set was established:

   • Ground Truth for Training Set: Not applicable in the context of a machine learning "training set". During the development of the immunoassay, known concentrations of MDMA in urine (spiked samples) would be used to develop the assay's dose-response curve and optimize its components, with the "ground truth" being the known, spiked concentrations verified by reference methods if necessary.

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