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VITROS Chemistry Products METD Reagent is used on VITROS 5,1 FS Chemistry Systems for the semi-quantitative or qualitative determination of methadone (METD) in human urine using a cutoff of either 150 ng/mL or 300 ng/mL. Measurements obtained with the VITROS METD method are used in the diagnosis and treatment of methadone use or overdose.

The VITROS Chemistry Products METD assay is intended for use by professional laboratory personnel. It provides only a preliminary test result. A more specific alternative chemical method must be used to confirm a result obtained with this assay. 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 evaluating a preliminary positive result.

For in vitro diagnostic use only. VITROS Chemistry Products Calibrator Kit 26 is used to calibrate VITROS 5,1 FS Chemistry Systems for the qualitative or semi-quantitative measurement of drugs of abuse.

For in vitro diagnostic use only. VITROS Chemistry Products DAT Performance Verifiers are assayed controls used to monitor performance of urine drugs of abuse screening assays on VITROS 5,1 FS Chemistry Systems.

The VITROS METD assay is a homogeneous enzyme immunoassay that is performed using the VITROS Chemistry Products METD Reagent in conjunction with the VITROS Chemistry Products Calibrator Kit 26 and VITROS Chemistry Products FS Diluent Pack 4 (DAT Diluent/DAT Diluent 2) on VITROS 5,1 FS Chemistry Systems.

The VITROS METD Reagent is a dual chambered package containing ready-to-use liquid reagents that are used to detect methadone in urine. Sample, calibrators, and controls are automatically treated with surfactant (DAT Diluent 2) prior to addition of reagents. Treated sample is added to Reagent 1 containing antibodies reactive to methadone, glucose-6-phosphate and nicotinamide adenine dinucleotide (NAD*), followed by Reagent 2 containing methadone labeled with the enzyme glucose-6-phosphate dehydrogenase (G6P-DH). The assay is based on competition between methadone in the treated urine sample and the methadone labeled with the enzyme glucose-6-phosphate dehydrogenase (G6P-DH) for antibody binding sites. Enzyme activity decreases upon binding to the antibody, therefore the concentration of methadone in the urine sample is directly proportional to measured enzyme activity. Active enzyme converts oxidized nicotinamide adenine dinucleotide (NAD*) to NADH, resulting in an absorbance change that is measured spectrophotometrically at 340 nm.

VITROS Chemistry Products Calibrator Kit 26 is prepared from human urine to which drugs of abuse, metabolites of drugs of abuse, organic salt, surfactants, and preservative have been added. VITROS Calibrator Kit 26 is a single fluid and from it six dilutions are performed by the VITROS 5,1 FS Chemistry System to create a total of six calibrators. These standards are used to calibrate VITROS 5,1 FS Chemistry Systems for the qualitative or semi-quantitative measurement of methadone (METD).

VITROS Chemistry Products DAT Performance Verifiers I, II, III, IV and V are prepared from a human urine pool to which analytes, surfactant, and preservative have been added. These are assayed controls used to monitor performance of the VITROS METD assay on VITROS 5,1 FS Chemistry Systems.

The VITROS Chemistry Products FS Diluent Pack 4 (DAT Diluent/ DAT Diluent 2) is a common reagent that is used with several drugs of abuse assays to dilute calibrators and samples on the VITROS 5,1 FS System. This is a dual chambered package containing two ready-to-use liquid diluents. DAT Diluent is prepared from human urine to which organic salt, surfactants, and preservative have been added. DAT Diluent 2 is prepared from processed water to which surfactant and preservative have been added.

The VITROS 5,1 FS Chemistry System is a clinical chemistry instrument that provides automated use of the VITROS Chemistry Products MicroTip® and MicroSlides® range of products. The VITROS 5,1 FS System was cleared for market by 510(k) premarket notification (K031924).

Here's a breakdown of the acceptance criteria and study information for the VITROS Chemistry Products METD Reagent, VITROS Chemistry Products Calibrator Kit 26, and VITROS Chemistry Products DAT Performance Verifiers, based on the provided document:

1. Table of Acceptance Criteria and Reported Device Performance

The document does not explicitly state "acceptance criteria" in a quantitative manner as one might find for a pass/fail threshold. Instead, it describes the results in terms of "good agreement" with the predicate device. The primary performance metric mentioned is agreement between the new device and the predicate device for methadone detection in urine.

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

• Test Set Sample Size: The document states that "patient samples" were used. However, it does not specify the number of patient samples in the test set.
• Data Provenance: The document does not explicitly state the country of origin or whether the study was retrospective or prospective. It uses the general term "patient samples," which typically implies prospective collection for such validation studies, but this is not explicitly confirmed.

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

This information is not provided in the document. For an in vitro diagnostic device for drug testing, "ground truth" is typically established by a more specific and accurate analytical method rather than human expert consensus.

4. Adjudication Method for the Test Set

This information is not applicable or provided for this type of in vitro diagnostic device study. Adjudication methods (like 2+1 or 3+1) are typically used in imaging or clinical evaluation studies where human readers are involved in interpreting results. For chemical assays, the comparison is typically against a reference method.

5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done, and the Effect Size of Human Improvement with AI vs. Without AI Assistance

• Was an MRMC study done? No.
• Effect size of human improvement with AI vs. without AI assistance: This information is not applicable as the device is an in vitro diagnostic assay, not an AI-assisted diagnostic tool for human readers.

6. If a Standalone (Algorithm Only Without Human-in-the-Loop Performance) Was Done

• Was a standalone study done? Yes. The study directly compares the performance of the VITROS METD assay (an automated chemical assay) against a predicate device on an automated analyzer. This is inherently a standalone performance evaluation of the assay itself.

7. The Type of Ground Truth Used

The ground truth for the test set was established by comparison to a predicate device, specifically the EMIT® II Plus Methadone Assay on the OLYMPUS® AU400 System. While not explicitly stated as "ground truth" in the document, in the context of substantial equivalence, the predicate device's established performance serves as the reference for the new device. For confirming positive results in drug-of-abuse testing, the document explicitly states that Gas Chromatography/Mass Spectrometry (GC/MS) is the preferred confirmatory method, implying that GC/MS would be the ultimate ground truth. However, the equivalence study itself was against another immunoassay.

8. The Sample Size for the Training Set

The document does not specify a separate "training set" or its size. For a chemical assay like this, the assay development and optimization phases would involve numerous samples, but these are generally not referred to as a "training set" in the same way as machine learning models. The calibration and control materials are described, but not a dataset used to "train" the underlying assay principle.

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

Since a "training set" is not explicitly defined in the context of this document, the method for establishing its ground truth is not provided. The calibrators and controls used for the assay are prepared with known concentrations of methadone, establishing their "ground truth" by design.

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