FDA 510(k) Search - By Innolitics (SaMD and AI Experts)

Wondfo Methamphetamine Urine Test (MET 300) is an immunochromatographic assay for the qualitative determination of D(+)-Methamphetamine in human urine at a Cut-Off concentration of 300 ng/mL. The test is available in a Dip Card format and a Cup format. This product is only intended for prescription use and is not intended for point-of-care use.

The test provides only preliminary test results. A more specific alternative chemical method must be used in order to obtain a confirmed analytical result. GC/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.

Wondfo Oxazepam Urine Test (BZO 200) is an immunochromatographic assay for the qualitative determination of Oxazepam in human urine at a Cut-Off concentration of 200 ng/mL. The test is available in a Dip Card format and a Cup format. This product is only intended for prescription use and is not intended for point-of-care use.

Device Description

Immunochromatographic assays for Methamphetamine and Oxazepam Urine Tests use a lateral flow, one step system for the qualitative detection of D(+)-Methamphetamine and Oxazepam (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. Oxazepam is part of the Benzodiazepine class of drugs of abuse.

AI/ML Overview

Here's a summary of the acceptance criteria and study details for the Wondfo Methamphetamine Urine Test (MET 300) and Wondfo Oxazepam Urine Test (BZO 200), based on the provided 510(k) summary:

Acceptance Criteria and Device Performance

The acceptance criteria for drug testing devices like these are typically based on the accurate classification of samples relative to a defined cut-off concentration. While explicit "acceptance criteria" percentages are not directly stated in the document, the precision and comparison studies demonstrate the device's ability to correctly identify samples around the cut-off.

The reported performance indicates that:

For concentrations below -25% Cut-Off, all samples were reported as Negative.
For concentrations at and above +25% Cut-Off, all samples were reported as Positive.

This suggests an implied acceptance criterion of 100% agreement for samples sufficiently far from the cut-off. For samples at the cut-off, a high percentage of positive results is expected, though not necessarily 100% due to inherent variability allowed around the cut-off.

Table of Acceptance Criteria and Reported Device Performance

Performance Characteristic	Acceptance Criteria (Implied)	Wondfo MET 300 Reported Performance (Cup/Dip Card)	Wondfo BZO 200 Reported Performance (Cup/Dip Card)
Precision	100% agreement for samples at/below -25% from cut-off. 100% agreement for samples at/above +25% from cut-off. High agreement for samples at cut-off.	Cup:
-100% to -25% Cut-off: 50-/0+ (100% Neg)
At Cut-off: 45-47+/3-5- (90-94% Pos)
+25% to +100% Cut-off: 50+/0- (100% Pos)
Dip Card:
-100% to -25% Cut-off: 50-/0+ (100% Neg)
At Cut-off: 44-45+/5-6- (88-90% Pos)
+25% to +100% Cut-off: 50+/0- (100% Pos)	Cup:
-100% to -25% Cut-off: 50-/0+ (100% Neg)
At Cut-off: 46-47+/3-4- (92-94% Pos)
+25% to +100% Cut-off: 50+/0- (100% Pos)
Dip Card:
-100% to -25% Cut-off: 50-/0+ (100% Neg)
At Cut-off: 45-46+/4-5- (90-92% Pos)
+25% to +100% Cut-off: 50+/0- (100% Pos)
Cut-off Verification	All positive at and above +25% Cut-off. All negative at and below -25% Cut-off.	All positive at and above +25% Cut-off. All negative at and below -25% Cut-off.	All positive at and above +25% Cut-off. All negative at and below -25% Cut-off.
Interference	No interference from common substances at 100 µg/mL.	Compounds listed show no interference at 100 µg/mL.	Compounds listed show no interference at 100 µg/mL.
Specificity	Demonstrate cross-reactivity profiles.	D(+)-Methamphetamine: 100%. Other amphetamines/substances show varying degrees of cross-reactivity.	Oxazepam: 100%. Other benzodiazepines/substances show varying degrees of cross-reactivity.
Urine Gravity/pH Effect	No effect on results when urine gravity is 1.000-1.035 or pH is 4-9.	All positive at and above +25% Cut-Off, all negative at and below -25% Cut-Off within specified ranges.	All positive at and above +25% Cut-Off, all negative at and below -25% Cut-Off within specified ranges.
Method Comparison	Good agreement with GC/MS across different concentration ranges.	Agreements shown in tables (performance varies slightly per viewer and format). For example, Viewer A (Cup) for MET 300 showed 0 false positives for drug-free, low negative, and high positive samples. Some discrepancies near cut-off.	Agreements shown in tables (performance varies slightly per viewer and format). For example, Viewer A (Cup) for BZO 200 showed 0 false positives for drug-free, low negative, and high positive samples. Some discrepancies near cut-off.

Study Details

Sample sizes used for the test set and the data provenance:
- Precision Study: For each drug (MET 300 and BZO 200) and each format (Cup, Dip Card), 8 concentrations were tested (-100%, -75%, -50%, -25%, Cut-off, +25%, +50%, +75%, +100% of cut-off).
  - Each concentration was tested two runs per day for 25 days across 3 lots of the device. This means for each distinct drug/format (e.g., MET 300 Cup), there were: 8 concentrations x 2 runs/day x 25 days/run x 3 lots = 1200 tests.
  - The exact number of unique "samples" is not explicitly stated beyond "samples prepared by spiking drug in negative samples." It implies contrived samples.
- Cut-off Verification: 150 samples were used (equally distributed at -50%, -25%, Cut-Off, +25%, +50% Cut-Off). These were tested using three different lots of each device by three different operators. (150 samples x 3 lots x 3 operators = 1350 tests per drug)
- Interference Study: "drug-free urine and target drugs urine with concentration at 25% below and 25% above Cut-Off level" were spiked with potential interferents. These were tested using three batches of each device for both Dip Card and Cup formats. The number of unique samples is not specified.
- Specificity Study: Various compounds were tested against three batches of each device for both Dip Card and Cup formats. The number of unique samples is not specified.
- Urine Specific Gravity and pH Effect: Urine samples with varying specific gravity (1.000~~1.035) or pH (4~~9) were spiked at -25% and +25% of Cut-Off. These were tested using three batches of each device for both Dip Card and Cup formats. The number of unique samples is not specified.
- Comparison Studies:
  - MET 300: 80 unaltered clinical samples were used (40 negative and 40 positive). These were tested by three laboratory assistants.
  - BZO 200: 80 unaltered clinical samples were used (40 negative and 40 positive). These were tested by three laboratory assistants.
- Data Provenance: The study was performed "in-house" and used "unaltered clinical samples" for the comparison studies. The country of origin of these clinical samples is not specified, but the submitter is from Guangzhou, P.R. China. The samples were likely retrospective, as they were "blind labeled" and then retrospectively compared to GC/MS results.
Number of experts used to establish the ground truth for the test set and the qualifications of those experts:
- Ground Truth Establishment: For the comparison studies, the ground truth was established by GC/MS (Gas Chromatography/Mass Spectrometry). This is considered the "preferred confirmatory method" and is an objective, analytical gold standard rather than expert consensus.
- No "experts" in the clinical sense (e.g., radiologists) were used to establish the ground truth; it was established by chemical analysis.
Adjudication method for the test set:
- For the comparison studies, the Wondfo results from each of the three "viewers" (laboratory assistants) were individually compared to the GC/MS ground truth. There is no mention of an adjudication process among the viewers' interpretations of the Wondfo device to reach a single "device" result; each viewer's interpretation stands separately. The GC/MS results serve as the objective truth against which each viewer's reading of the rapid test is compared.
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:
- No, a multi-reader multi-case (MRMC) comparative effectiveness study was not done.
- This device is a rapid diagnostic test based on immunochromatography, not an AI-based imaging or interpretive device. Therefore, there is no AI component, and no effect size for human readers with and without AI assistance is applicable or reported.
If a standalone (i.e. algorithm only without human-in-the loop performance) was done:
- No, a standalone (algorithm-only) performance study was not done in the context of AI.
- This is a qualitative rapid diagnostic test where human observation of a colored line determines the result. While the chemical reaction is the "algorithm," the interpretation traditionally involves a human "in-the-loop." The precision studies and cut-off verification can be considered standalone performance in the sense that the device's chemical reactions perform consistently with known spiked concentrations, but the final reading is still noted as being performed by operators/viewers.
The type of ground truth used:
- GC/MS (Gas Chromatography/Mass Spectrometry) was used as the ground truth for confirming drug concentrations in samples for the precision studies, cut-off verification, and method comparison studies. This is a highly accurate and objective analytical method.
The sample size for the training set:
- The document describes performance studies for the device, which are typically analogous to validation or test sets. There is no mention of a "training set" in the context of machine learning or AI, as this is a traditional immunochromatographic assay.
- The document implies that the device (likely the antibodies and reagent concentrations) was developed through an internal R&D process, but no specific dataset labeled as a "training set" with associated size is disclosed here.
How the ground truth for the training set was established:
- As no "training set" for an algorithm is described, this question is not applicable. The components of the assay (antibodies, drug-protein conjugates) would have been developed based on known chemical specificities and binding affinities, likely validated against known concentrations of analytes, but not in the format of a "ground truth for a training set" as it would be for an AI model.

Summary

Regulation Number and Section

§ 862.3610 Methamphetamine test system.

(a)
Identification. A methamphetamine test system is a device intended to measure methamphetamine, a central nervous system stimulating drug, in serum, plasma, and urine. Measurements obtained by this device are used in the diagnosis and treatment of methamphetamine use or overdose.(b)
Classification. Class II (special controls). A methamphetamine 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).