(29 days)
SAFECARE® THC Urine Strip Test is a competitive binding, lateral flow immunochromatographic assay for qualitative detection of Marijuana in human urine at the cutoff concentrations of 50 ng/mL.
The test provides only preliminary test results. A more specific alternative chemical must be used in order to obtain a confirmed analytical result. GC/MS or LC/MS is the preferred confirmatory method.
The test is intended for over-the-counter use.
SAFECARE® THC Urine Strip Test devices are immunochromatographic assays for the qualitative detection of 11-nor-A9-THC-9 COOH (target analyte) in human urine. The product is a single-use in vitro diagnostic device. It contains a Test Device and a package insert. Each test device is sealed with a desiccant in an aluminum pouch.
The provided document outlines the acceptance criteria and performance data for the SAFECARE® THC Urine Strip Test, which is a qualitative lateral flow immunoassay for detecting Marijuana in human urine.
Here's the breakdown of the requested information:
1. Table of Acceptance Criteria and Reported Device Performance
The document does not explicitly state formal "acceptance criteria" for precision or accuracy using specific numerical thresholds (e.g., >95% agreement). Instead, it presents the results of various performance studies. The overall acceptance is inferred from the device being deemed "substantially equivalent" to a predicate device.
However, based on the performance characteristics, we can infer performance goals for accuracy at different concentrations relative to the cutoff.
| Acceptance Criteria Category | Specific Metric (Inferred) | Acceptance Threshold (Inferred/Observed) | Reported Device Performance | Comments on Performance |
|---|---|---|---|---|
| Analytical Performance | ||||
| Precision | Agreement at various | High agreement expected, especially | ||
| concentrations | at concentrations further from cutoff. | |||
| -100% Cut-off | 100% Negative (0% Positive) | Lot 1, 2, 3: 50-/0+ | Meets expectation | |
| -75% Cut-off | 100% Negative (0% Positive) | Lot 1, 2, 3: 50-/0+ | Meets expectation | |
| -50% Cut-off | 100% Negative (0% Positive) | Lot 1, 2, 3: 50-/0+ | Meets expectation | |
| -25% Cut-off | 100% Negative (0% Positive) | Lot 1, 2, 3: 50-/0+ | Meets expectation | |
| Cut-off (50 ng/mL) | ~50% Positive, ~50% Negative | Lot 1, 2: 25-/25+; Lot 3: | Meets expectation | |
| 26-/24+ | ||||
| +25% Cut-off | 100% Positive (0% Negative) | Lot 1, 2, 3: 50+/0- | Meets expectation | |
| +50% Cut-off | 100% Positive (0% Negative) | Lot 1, 2, 3: 50+/0- | Meets expectation | |
| +75% Cut-off | 100% Positive (0% Negative) | Lot 1, 2, 3: 50+/0- | Meets expectation | |
| +100% Cut-off | 100% Positive (0% Negative) | Lot 1, 2, 3: 50+/0- | Meets expectation | |
| Interference | No interference from | No false positives or negatives due to | Compounds at 100µg/mL | No interference reported |
| common substances | specified interfering substances when | (list provided) showed no | ||
| drug is absent or present above cutoff | interference. | |||
| Specificity | Cross-reactivity with | Low or no cross-reactivity with | Provided specific cross- | Demonstrated specificity |
| related compounds | non-target compounds. | reactivity percentages for | ||
| related cannabinoids. | ||||
| Urine Specific Gravity | Correct results across | Correct classification (negative for | Samples from 1.000 to 1.035 | Device performs reliably |
| range of SG | -25% cutoff, positive for +25% cutoff). | with THC at +/-25% cutoff | across range of urine SG | |
| showed expected results. | ||||
| Urine pH | Correct results across | Correct classification (negative for | Samples from pH 4 to 9 with | Device performs reliably |
| range of pH | -25% cutoff, positive for +25% cutoff). | THC at +/-25% cutoff | across range of urine pH | |
| showed expected results. | ||||
| Comparison Studies | Agreement with LC/MS | High agreement between device results | ||
| for clinical samples | and LC/MS, particularly for samples | |||
| not near the cutoff. | ||||
| Overall Agreement | Not explicitly quantified, but inferred | Viewer A: 78/80 (97.5%) | High agreement for | |
| from discordant results. | Viewer B: 78/80 (97.5%) | human readers | ||
| Viewer C: 79/80 (98.75%) | ||||
| Lay-User Study | Ease of use | Instructions are easily understood. | All lay users indicated | Instructions are clear |
| instructions were easy to | ||||
| Accuracy of self-testing | High percentage of correct results, | |||
| decreasing near the cutoff. | ||||
| -100% Cutoff | 100% agreement | 100% Correct | Excellent | |
| -75% Cutoff | 100% agreement | 100% Correct | Excellent | |
| -50% Cutoff | 100% agreement | 100% Correct | Excellent | |
| -25% Cutoff | >90% agreement, with expected | 90% Correct | Acceptable, slight dip | |
| increase in discordance. | near cutoff. | |||
| +25% Cutoff | >90% agreement, with expected | 95% Correct | Acceptable, slight dip | |
| increase in discordance. | near cutoff. | |||
| +50% Cutoff | 100% agreement | 100% Correct | Excellent | |
| +75% Cutoff | 100% agreement | 100% Correct | Excellent |
2. Sample Size Used for the Test Set and Data Provenance
- Precision Study:
- Sample Size: 9 different concentrations, with 50 tests performed for each concentration per lot (2 runs per day for 25 days). Since 3 lots were tested, this amounts to 9 concentrations * 50 tests/lot * 3 lots = 1350 tests in total for the precision study itself. The samples were prepared by spiking drug in "negative samples." The provenance is not explicitly stated but implies laboratory-prepared samples.
- Comparison Studies (Clinical Samples):
- Sample Size: 80 unaltered clinical samples (40 negative and 40 positive).
- Data Provenance: The document states "unaltered clinical samples." The country of origin for these clinical samples is not specified. It is a retrospective analysis as the samples were collected and then tested.
- Lay-User Study:
- Sample Size: 140 lay persons tested individual samples. There were 7 concentration levels, with 20 samples per concentration. So, 7 concentrations * 20 samples/concentration = 140 samples in total.
- Data Provenance: The samples were "spiked drug THC into drug free-pooled urine specimens." The country of origin is not specified. It is a prospective study in the sense that the lay users tested the devices with prepared samples, but the samples themselves were laboratory-prepared.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Their Qualifications
- Precision Study: The ground truth was established by laboratory preparation of samples with known concentrations confirmed by LC/MS. No human experts are explicitly mentioned for ground truth.
- Comparison Studies (Clinical Samples): The ground truth was established by LC/MS results. "LC/MS is the preferred confirmatory method." The number of LC/MS operators or analysts is not specified, nor are their qualifications.
- Lay-User Study: The ground truth for the prepared urine samples was established by LC/MS. The number of LC/MS operators or analysts is not specified, nor are their qualifications.
4. Adjudication Method for the Test Set
- Precision Study: Not applicable, as results were quantitative (known concentrations) rather than subjective interpretations needing adjudication.
- Comparison Studies (Clinical Samples): The document mentions "three different laboratory assistants" performing the tests. Their results were compared to LC/MS. There is no explicit adjudication method stated for discrepancies between human readers or between human readers and LC/MS. The discordant results table simply lists them.
- Lay-User Study: Not explicitly stated. Each lay person provided their own result. Their individual results were then compared to the LC/MS confirmed concentration.
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done, and the Effect Size of How Much Human Readers Improve with AI vs without AI Assistance
- No, an MRMC comparative effectiveness study was not done.
- This device is a standalone diagnostic strip test intended for visual interpretation, not an AI-assisted diagnostic tool. Therefore, there is no AI component or human readers improving with/without AI assistance.
6. If a Standalone (i.e. algorithm only without human-in-the-loop performance) Was Done
- Yes, in essence, the "device performance" in all studies represents a standalone performance relative to the ground truth (LC/MS). The device itself (the strip test) produces a visual result. While a human reads the result, the performance studies assess the accuracy of the device's output (presence/absence of a line) against known concentrations.
- For the "Comparison Studies," the performance of the "Safecare THC Urine Strip Test" is measured for each viewer by comparing their reading of the device against LC/MS. This measures the combined device-human performance.
- For the "Lay-User Study," it also measures the combined device-lay user performance.
7. The Type of Ground Truth Used
- For all performance studies (Precision, Comparison, Lay-User), the ground truth was primarily established by LC/MS (Liquid Chromatography-Mass Spectrometry). This is a highly accurate and quantitative laboratory method.
- For the precision study, it specifies "THC drug concentration was confirmed by LC/MS."
- For the comparison studies, it states "The samples were blind labeled and compared to LC/MS results. LC/MS is the preferred confirmatory method."
- For the lay-user study, it states "The concentrations of the samples were confirmed by LC/MS."
8. The Sample Size for the Training Set
- Based on the provided document, this is a 510(k) submission for a diagnostic device. Such submissions typically focus on analytical and clinical performance validation rather than explicitly detailing a "training set" for an algorithm.
- There is no information provided regarding a "training set" as this is not an AI/machine learning device. The immunoassay device relies on chemical reactions, not on data training.
9. How the Ground Truth for the Training Set Was Established
- As there is no mention of a "training set" or an algorithm that requires training, this question is not applicable based on the provided document.
§ 862.3870 Cannabinoid test system.
(a)
Identification. A cannabinoid test system is a device intended to measure any of the cannabinoids, hallucinogenic compounds endogenous to marihuana, in serum, plasma, saliva, and urine. Cannabinoid compounds includedelta -9-tetrahydrocannabinol, cannabidiol, cannabinol, and cannabichromene. Measurements obtained by this device are used in the diagnosis and treatment of cannabinoid use or abuse and in monitoring levels of cannabinoids during clinical investigational use.(b)
Classification. Class II (special controls). A cannabinoid 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).