(47 days)
Wondfo Cocaine Urine Test (COC 100) is an immunochromatographic assay for the qualitative determination of Benzoylecgonine in human urine at a Cut-Off concentration of 100 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 Cannabinoids Urine Test (THC 40) is an immunochromatographic assay for the qualitative determination of 11-nor-A9-THC-9-COOH in human urine at a Cut-Off concentration of 40 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.
Immunochromatograph assays for Cocaine and Cannabinoids Urine Tests use a lateral flow, for the for step system qualitative detection of Benzoylecgonine and one 11-nor-A9-THC-9-COOH (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.
This document describes the performance of the Wondfo Cocaine Urine Test (COC 100) and Wondfo Cannabinoids Urine Test (THC 40). The acceptance criteria and the study results are detailed below.
1. Table of Acceptance Criteria and Reported Device Performance
The document does not explicitly state formal acceptance criteria in terms of specific percentages for agreement, sensitivity, or specificity. However, the precision studies and comparison studies implicitly demonstrate the expected performance around the cut-off values. For the purpose of this summary, we will interpret the demonstrated ability to correctly identify positive and negative samples, particularly around the cut-off, as the acceptance criteria.
COC 100 (Cocaine Urine Test) - Cup Format
| Performance Characteristic | Acceptance Criteria (Implied from Study Design) | Reported Device Performance (Worst Case for a single Viewer) |
|---|---|---|
| Precision (Analytical) | All negative samples below -25% Cut-Off should be negative. All positive samples above +25% Cut-Off should be positive. Cut-Off samples may show mixed results. | -100% to -25% Cut-Off: All 50 samples per lot/concentration were negative (50-/0+). |
| +25% to +100% Cut-Off: All 50 samples per lot/concentration were positive (50+/0-). | ||
| At Cut-Off: Viewer C: 47+/3- (47 positive, 3 negative out of 50) | ||
| Comparison Study | High agreement with GC/MS for drug-free, low negative, and high positive samples. Reasonable agreement near cut-off. | Drug-free: All 10 samples were negative. |
| Low Negative: All 15 samples were negative. | ||
| Near Cut-Off Negative: 13 or 14 negative, 1 or 2 positive. | ||
| Near Cut-Off Positive: All 27 samples were positive. | ||
| High Positive: All 13 samples were positive. |
COC 100 (Cocaine Urine Test) - Dip Card Format
| Performance Characteristic | Acceptance Criteria (Implied from Study Design) | Reported Device Performance (Worst Case for a single Viewer) |
|---|---|---|
| Precision (Analytical) | All negative samples below -25% Cut-Off should be negative. All positive samples above +25% Cut-Off should be positive. Cut-Off samples may show mixed results. | -100% to -25% Cut-Off: All 50 samples per lot/concentration were negative (50-/0+). |
| +25% to +100% Cut-Off: All 50 samples per lot/concentration were positive (50+/0-). | ||
| At Cut-Off: Viewer A and C: 45+/5- (45 positive, 5 negative out of 50) | ||
| Comparison Study | High agreement with GC/MS for drug-free, low negative, and high positive samples. Reasonable agreement near cut-off. | Drug-free: All 10 samples were negative. |
| Low Negative: All 15 samples were negative. | ||
| Near Cut-Off Negative: 12 or 13 negative, 2 or 3 positive. | ||
| Near Cut-Off Positive: All 27 samples were positive. | ||
| High Positive: All 13 samples were positive. |
THC 40 (Cannabinoids Urine Test) - Cup Format
| Performance Characteristic | Acceptance Criteria (Implied from Study Design) | Reported Device Performance (Worst Case for a single Viewer) |
|---|---|---|
| Precision (Analytical) | All negative samples below -25% Cut-Off should be negative. All positive samples above +25% Cut-Off should be positive. Cut-Off samples may show mixed results. | -100% to -25% Cut-Off: All 50 samples per lot/concentration were negative (50-/0+). |
| +25% to +100% Cut-Off: All 50 samples per lot/concentration were positive (50+/0-). | ||
| At Cut-Off: Viewer A and B: 45+/5- (45 positive, 5 negative out of 50) | ||
| Comparison Study | High agreement with GC/MS for drug-free, low negative, and high positive samples. Reasonable agreement near cut-off. | Drug-free: All 10 samples were negative. |
| Low Negative: All 13 samples were negative. | ||
| Near Cut-Off Negative: 14, 15 or 16 negative, 1, 2 or 3 positive. | ||
| Near Cut-Off Positive: All 20 samples were positive. | ||
| High Positive: All 20 samples were positive. |
THC 40 (Cannabinoids Urine Test) - Dip Card Format
| Performance Characteristic | Acceptance Criteria (Implied from Study Design) | Reported Device Performance (Worst Case for a single Viewer) |
|---|---|---|
| Precision (Analytical) | All negative samples below -25% Cut-Off should be negative. All positive samples above +25% Cut-Off should be positive. Cut-Off samples may show mixed results. | -100% to -25% Cut-Off: All 50 samples per lot/concentration were negative (50-/0+). |
| +25% to +100% Cut-Off: All 50 samples per lot/concentration were positive (50+/0-). | ||
| At Cut-Off: Viewer B and C: 45+/5- (45 positive, 5 negative out of 50) | ||
| Comparison Study | High agreement with GC/MS for drug-free, low negative, and high positive samples. Reasonable agreement near cut-off. | Drug-free: All 10 samples were negative. |
| Low Negative: All 13 samples were negative. | ||
| Near Cut-Off Negative: 14 or 15 negative, 2 or 3 positive. | ||
| Near Cut-Off Positive: All 20 samples were positive. | ||
| High Positive: All 20 samples were positive. |
2. Sample size used for the test set and the data provenance
-
Precision Studies (Analytical Performance):
- For each drug (COC 100 and THC 40), for each format (Cup and Dip Card), and for each of 3 lots:
- 9 concentrations were tested (-100%, -75%, -50%, -25%, Cut-Off, +25%, +50%, +75%, +100% of cut-off).
- Each concentration was tested by performing 2 runs per day for 25 days.
- Total samples per lot/concentration: 2 runs/day * 25 days = 50 samples.
- Total samples for precision study: 2 drugs * 2 formats * 3 lots * 9 concentrations * 50 samples/concentration = 5400 samples.
- Data Provenance: The samples were "prepared by spiking drug in negative samples" and confirmed by GC/MS. This indicates controlled laboratory conditions, likely in China (country of origin of the submitter). Given the preparation method, this is considered a prospective study for analytical precision.
- For each drug (COC 100 and THC 40), for each format (Cup and Dip Card), and for each of 3 lots:
-
Comparison Studies:
- COC 100: 80 "unaltered clinical samples" were tested.
- THC 40: 80 "unaltered clinical samples" were tested.
- Total samples for comparison study: 160 samples (80 for COC 100, 80 for THC 40).
- Data Provenance: The samples are described as "unaltered clinical samples." The country of origin is not explicitly stated, but given the submitter, it is likely China. These are retrospective samples as they were clinical samples already collected.
3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts
- Ground Truth for Analytical Performance (Precision): The ground truth was established by preparing samples with known concentrations by spiking negative samples and confirming them with GC/MS. No human experts were involved in establishing this ground truth beyond the laboratory personnel performing the spiking and GC/MS confirmation.
- Ground Truth for Comparison Studies: The ground truth for the 160 clinical samples was established using GC/MS (Gas Chromatography/Mass Spectrometry), which is the "preferred confirmatory method" as stated in the intended use. No human experts interpreted the GC/MS results for the purpose of establishing ground truth for the comparison study itself, as GC/MS is an objective analytical method.
4. Adjudication method for the test set
- Analytical Performance (Precision): Not applicable. The results were observations of whether a test line appeared or not, based on known spiked concentrations.
- Comparison Studies: The "Wondfo Result" for each clinical sample was determined by three "laboratory assistants" (Viewer A, B, C). Their readings were then compared against the GC/MS ground truth. There is no explicit mention of an adjudication method (like 2+1 or 3+1 consensus) among the three viewers to decide a single "device result" when their readings differed. Instead, the results for each viewer are presented individually in the tables, and discordant results for each viewer are also listed separately. This suggests individual reader performance was being assessed against the GC/MS, rather than a single adjudicated device reading.
5. 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 explicitly done in the context of comparing human readers with and without AI assistance. This device is a rapid diagnostic test where the result (presence/absence of a line) is interpreted directly by a human viewer. The "viewers" in the comparison study are reading the device's output, not interpreting medical images or complex data. The study compares the device's performance (as read by individual human viewers) against GC/MS, not human readers' diagnostic accuracy with vs. without AI.
6. 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. This device is an immunochromatographic assay that produces a visual result (a line) that requires a human to interpret as positive or negative. It is not an automated analytical instrument or an AI system that provides its own output. The "Wondfo Result" in the comparison study is the human interpretation of the device.
7. The type of ground truth used (expert consensus, pathology, outcomes data, etc)
- For both the precision studies and the comparison studies, the ground truth was based on analytical chemical methods.
- Precision Studies: Known concentrations of drugs spiked into negative urine, verified by GC/MS.
- Comparison Studies: GC/MS (Gas Chromatography/Mass Spectrometry) results for "unaltered clinical samples." GC/MS is considered the gold standard for confirming drug presence and concentration.
8. The sample size for the training set
- This document describes performance characteristics of a rapid diagnostic test, not a machine learning or AI model. Therefore, there is no "training set" in the context of algorithm development. The device's design and manufacturing processes are developed through internal R&D, not by training on a dataset in the way an AI algorithm would be.
9. How the ground truth for the training set was established
- As there is no training set for an AI/ML algorithm described, this question is not applicable.
§ 862.3250 Cocaine and cocaine metabolite test system.
(a)
Identification. A cocaine and cocaine metabolite test system is a device intended to measure cocaine and a cocaine metabolite (benzoylecgonine) in serum, plasma, and urine. Measurements obtained by this device are used in the diagnosis and treatment of cocaine use or overdose.(b)
Classification. Class II (special controls). A cocaine and cocaine metabolite 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).