(26 days)
Wondfo Amphetamine Urine Test is an immunochromatographic assay for the qualitative determination of d-Amphetamine in human urine at a cutoff concentration of 1000ng/mL. The test is available in a dip card format and a cup format. It is intended for prescription use and over the counter use.
The test provides only preliminary test results. A more specific alternative chemical method must be used in order to obtain a conformed analytical result. GCMS 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 Secobarbital Urine Test is an immunochromatographic assay for the qualitative determination of Secobarbital (major metabolite of Barbiturates) in human urine at a cutoff concentration of 300ng/mL. The test is available in a dip card format and a cup format. It is intended for prescription use and over the counter use.
The test provides only preliminary test results. A more specific alternative chemical method must be used in order to obtain a conformed analytical result. GCMS 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 is an immunochromatographic assay for the qualitative determination of Oxazepam (major metabolite of Benzodiazepines) in human urine at a cutoff concentration of 300ng/mL. The test is available in a dip card format and a cup format. It is intended for prescription use and over the counter use.
The test provides only preliminary test results. A more specific alternative chemical must be used in order to obtain a conformed analytical result. GCMS 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 Amphetamine, Secobarbital, and Oxazepam Urine Tests use a lateral flow, one step system for the qualitative detection of d-Amphetamine , Secobarbital, 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.
The acceptance criteria and study proving the device meets them are detailed below, based on the provided text.
1. Table of Acceptance Criteria and Reported Device Performance
The acceptance criteria are implied by the performance characteristics demonstrated in the precision and comparison studies, particularly the accuracy against GC/MS. The document does not explicitly state pre-defined acceptance criteria values for agreement percentages, but the reported performance serves as the basis for substantial equivalence.
Implied Acceptance Criteria and Reported Device Performance (Cup and Dip Card Formats):
| Drug | Concentration (relative to cutoff) | Implied Acceptance Criteria (Agreement with GC/MS) | Reported Performance (Cup Format) | Reported Performance (Dip Card Format) |
|---|---|---|---|---|
| Amphetamine | Negative | High agreement (e.g., ≥95-100%) | 100% | 100% |
| -75% | High agreement (e.g., ≥95-100%) | 100% | 100% | |
| -50% | High agreement (e.g., ≥95-100%) | 100% | 100% | |
| -25% | High agreement (e.g., ≥85-95%) | 90% | 85% | |
| +25% | High agreement (e.g., ≥85-95%) | 95% | 95% | |
| +50% | High agreement (e.g., ≥95-100%) | 100% | 100% | |
| +75% | High agreement (e.g., ≥95-100%) | 100% | 100% | |
| Secobarbital | Negative | High agreement (e.g., ≥95-100%) | 100% | 100% |
| -75% | High agreement (e.g., ≥95-100%) | 100% | 100% | |
| -50% | High agreement (e.g., ≥95-100%) | 100% | 100% | |
| -25% | High agreement (e.g., ≥85-95%) | 90% | 85% | |
| +25% | High agreement (e.g., ≥85-95%) | 90% | 90% | |
| +50% | High agreement (e.g., ≥95-100%) | 100% | 100% | |
| +75% | High agreement (e.g., ≥95-100%) | 100% | 100% | |
| Oxazepam | Negative | High agreement (e.g., ≥95-100%) | 100% | 100% |
| -75% | High agreement (e.g., ≥95-100%) | 100% | 100% | |
| -50% | High agreement (e.g., ≥95-100%) | 100% | 100% | |
| -25% | High agreement (e.g., ≥85-95%) | 90% | 95% | |
| +25% | High agreement (e.g., ≥85-95%) | 95% | 95% | |
| +50% | High agreement (e.g., ≥95-100%) | 100% | 100% | |
| +75% | High agreement (e.g., ≥95-100%) | 100% | 100% |
Note: The document implies acceptance by presenting these agreement percentages, suggesting they meet the regulatory expectations for accuracy in qualitative drug tests, especially around the cutoff concentrations where some variability is expected and observed.
2. Sample Size Used for the Test Set and Data Provenance
The comparison studies used 80 unaltered clinical samples for each drug (40 negative and 40 positive).
The samples were "blind labeled."
The provenance refers to "unaltered clinical samples," implying they were genuine human urine samples from a clinical setting, but the country of origin is not specified. The study is retrospective in the sense that the samples were analyzed and then compared to a previously established ground truth (GC/MS).
For the lay user studies, for each drug and each format (cup/dip card):
- 140 lay persons were used.
- 140 samples were tested for each specific drug and format combination, prepared at various concentrations (Negative, +/-75%, +/-50%, +/-25% of cutoff) by spiking drug(s) into drug-free pooled urine specimens.
- This means a total of (7 concentrations * 20 samples per concentration) = 140 samples were used for each drug. So, each of the 140 lay persons likely tested one sample.
- The provenance for these samples is that they were "prepared" by spiking drug(s) into "drug-free pooled urine specimens." This suggests a controlled laboratory setting, not necessarily directly collected clinical samples. The country of origin is not specified. This study is also retrospective in how samples were evaluated against a known ground truth.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Their Qualifications
The primary ground truth for the comparison studies was GC/MS (Gas Chromatography/Mass Spectrometry) results. GC/MS is a laboratory analytical method for specific compound identification and quantification and does not involve human experts establishing the ground truth in the same way, for example, a radiologist establishes ground truth for imaging. Samples' concentrations were "confirmed by GC/MS."
For the in-house comparison study, three laboratory assistants with relevant experience and one lay person with no experience other than reading instructions were used as "viewers" for the device result. Their role was to interpret the device's outcome, not to establish the ground truth for the presence or absence of the drug, which was done by GC/MS.
For the lay user study, 140 lay persons (with diverse educational and professional backgrounds, aged 21 to >50) interpreted the device results after reading instructions. Again, their role was to interpret the device, not establish the ground truth.
4. Adjudication Method for the Test Set
The document does not explicitly state an adjudication method (like 2+1, 3+1 consensus) for establishing the ground truth or resolving discrepancies between GC/MS and device readings. The GC/MS result is presented as the definitive truth. Discrepancies between the device reader's interpretation and the GC/MS result are simply noted in the "Discordant table," but no further adjudication process is described for those specific discrepancies.
5. If a Multi Reader Multi Case (MRMC) Comparative Effectiveness Study Was Done, and Effect Size of Human Improvement
A formal MRMC comparative effectiveness study, as typically understood (e.g., comparing human readers with and without AI assistance on diagnosis accuracy), was not performed. The studies involved multiple "viewers" (laboratory assistants and lay persons) interpreting the rapid test results, but this is a multi-reader study of device performance, not direct "human reader improvement with AI vs. without AI assistance." This device is an immunoassay, not an AI-powered diagnostic. Therefore, no effect size of human improvement with AI assistance is applicable or reported.
6. If a Standalone (i.e. algorithm only without human-in-the-loop performance) Was Done
This device is a rapid immunoassay test. Its mechanism relies on chemical reactions and visual interpretation of colored lines, not an algorithm. Therefore, the concept of "standalone (algorithm only without human-in-the-loop performance)" does not apply to this type of device. The device's "performance" is inherently based on a human reading the test result.
7. The Type of Ground Truth Used
The ground truth used for both the in-house comparison study and the lay user study was GC/MS (Gas Chromatography/Mass Spectrometry). This is a highly accurate and generally accepted method for confirming the presence and concentration of specific substances in toxicology.
8. The Sample Size for the Training Set
The document describes the device's performance characteristics (precision, linearity, stability, cut-off, interference, specificity) and then "Comparison Studies" and "Lay User Studies." It does not explicitly mention a "training set" for the device itself, as it is a chemical immunoassay, not a machine learning model that typically requires a training set. The descriptions of device development and analytical performance relate to the overall design and validation of the chemical components and detection mechanism.
9. How the Ground Truth for the Training Set Was Established
Since a "training set" in the context of machine learning is not applicable to this immunoassay device, the method for establishing its ground truth is also not applicable. The device's functionality is based on established biochemical principles and extensive internal analytical validation described in the "Analytical Performance" section (e.g., precision, specificity, interference against defined cut-off values), rather than being "trained" on a dataset.
§ 862.3100 Amphetamine test system.
(a)
Identification. An amphetamine test system is a device intended to measure amphetamine, a central nervous system stimulating drug, in plasma and urine. Measurements obtained by this device are used in the diagnosis and treatment of amphetamine use or overdose and in monitoring levels of amphetamine to ensure appropriate therapy.(b)
Classification. Class II (special controls). An amphetamine 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).