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Wondfo Buprenorphine Urine Test is an immunochromatographic assay for the qualitative determination of Buprenorphine in human urine at a cutoff concentration of 10 ng/mL. The test is available in a dip card format and a cup format. It is intended for over the counter use.

The Buprenorphine assay will yield preliminary positive results when Buprenorphine is ingested at or above therapeutic doses. There are no uniformly recognized drug levels for buprenorphine in urine. The Wondfo Buprenorphine Urine Test shows the drug was or was not present at the cutoff level. The test provides only preliminary test results. A more specific alternative chemical method must be used in order to obtain a conformed analytical result. 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 result is positive.

The device does not differentiate between drug abuse and prescription use of buprenorphine.

Immunochromatograph assays for Buprenorphine Urine Tests use a lateral flow, one step system for the qualitative detection of Buprenorphine (target analyte) in human urine. Each assay uses a monoclonal antibody-dye conjugate against drugs with gold chloride and fixed drug-protein conjugates and anti-mouse IgG polyclonal antibody in membranes.

Here's a breakdown of the acceptance criteria and study information for the Wondfo Buprenorphine Urine Test, based on the provided text:

Acceptance Criteria and Device Performance

The provided text only explicitly states the performance for the lay-user study as percentages of agreement with GC/MS. This can be interpreted as the acceptance criteria for user comprehension and accurate result interpretation by lay users.

Note: The acceptance criteria are inferred based on the observed high agreement for most concentrations. The 90.0% and 95.0% performance at +/-25% cutoff suggests a tolerance for slight variations near the cutoff, which is common in qualitative assays.

Study Information

2. Sample Size and Data Provenance:

• Test Set Sample Size (Lay-user study):
  • Cup format: 140 lay persons were involved. The urine samples were prepared at 7 different concentrations, with 20 samples per concentration. So, a total of 140 urine samples were tested.
  • Dip Card format: 140 lay persons were involved. The urine samples were prepared at 7 different concentrations, with 20 samples per concentration. So, a total of 140 urine samples were tested.
• Data Provenance: The study was performed at "three intended user sites." The country of origin is not explicitly stated, but the manufacturer is "Guangzhou Wondfo Biotech Co., Ltd." in Guangzhou, P.R. China. The study appears to be a prospective user study, as participants were provided with blind-labeled samples and devices for testing.

3. Number of Experts and Qualifications for Ground Truth:

• Number of Experts: Not applicable. The ground truth for the test set was established by objective chemical analysis (GC/MS), not by expert interpretation of the device results.
• Qualifications of Experts: Not applicable.

4. Adjudication Method for the Test Set:

• Adjudication Method: Not applicable. The ground truth was established by GC/MS, which is a definitive chemical method and does not require adjudication of human interpretations. The lay users performed the test and recorded the results, which were then compared to the GC/MS confirmed concentrations.

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

• MRMC Study Done: No, an MRMC comparative effectiveness study was not done. This study focuses on the agreement of lay users with the device results compared to a gold standard (GC/MS), not on comparing human reader performance with and without AI assistance.

6. Standalone Performance Study:

• Standalone Study Done: Yes, in essence, the "Lay-user study" is a standalone performance study in the context of Over-the-Counter (OTC) use. It evaluates the device's ability to provide accurate results when used by its intended end-users (lay persons) without professional intervention. The device's output (positive/negative) is directly compared to the true concentration.
  • The document also references "Analytical Performance" and "Comparison Studies" in predicate K113624, implying that a more technical standalone analytical performance (measuring sensitivity, specificity, accuracy against known concentrations) would have been performed and documented in the predicate device’s submission.

7. Type of Ground Truth Used:

• Ground Truth Type: Objective chemical analysis, specifically GC/MS. The concentrations of urine samples were "confirmed by GC/MS."

8. Sample Size for the Training Set:

• Training Set Sample Size: The document does not provide information about a "training set" or explicit details of the algorithm's development. This is a point-of-care immunoassay, not an AI device in the modern sense. Therefore, the concept of a training set for an algorithm is not directly applicable here. The device's performance relies on its physical and chemical properties developed through traditional R&D, not machine learning.

9. How the Ground Truth for the Training Set was Established:

• Ground Truth Establishment for Training Set: Not applicable, as there isn't a "training set" in the context of an algorithm. The development of such immunoassay devices typically involves extensive analytical testing of various concentrations and interfering substances to optimize the performance characteristics (e.g., antibody specificity, cutoff concentration calibration), which would form the "ground truth" for its design and manufacturing.

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