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The SAFElife™ Fentanyl Urine Home Test (Cassette) is a competitive binding, lateral flow immunochromatographic assay for qualitative detection of Fentanyl in human urine at cutoff concentration of 1 ng/mL.

For in vitro diagnostic use. For Over The Counter (OTC) use.

The test provides only preliminary test results. To obtain a confirmed analytical result, a more specific alternate chemical method must be used. Chromatography/Mass Spectrometry (GC/MS) or Liquid Chromatography/Tandem Mass Spectrometry (LC/MS-MS) is the recommended confirmatory method.

The SAFElife™ Fentanyl (FTY) Urine Test Cassette is a competitive binding, lateral flow immunochromatoqraphic assay for qualitative detection of Fentanyl (FTY) in human urine at cutoff concentration of 1 ng/mL.

For in vitro diagnostic use.

lt is not intended to distinquish between prescription drug or abuse of the drug. Clinical consideration and professional judgment should be applied to the drug of abuse test result, particularly in evaluating a preliminary positive result.

The SAFElife™ T-Dip Fentanyl Urine Home Test (Dip Card) is a competitive binding, lateral flow immunochromatographic assay for qualitative detection of Fentanyl in human urine at cutoff concentration of 1 ng/mL.

For in vitro diagnostic use. For Over The Counter (OTC) use.

The SAFElife™ T-Dip Fentanyl (FTY) Urine Test Panel is a competitive binding, lateral flow immunochromatographic assay for qualitative detection of Fentanyl (FTY) in human urine at cutoff concentration of 1 ng/mL.

For in vitro diagnostic use.

It is not intended to distinguish between prescription drug or abuse of the drug. Clinical consideration and professional judgment should be applied to the drug of abuse test result, particularly in evaluating a preliminary positive result. The test provides only preliminary test results. To obtain a confirmed analytical result, a more specific alternate chemical must be used. Chromatography/Mass Spectrometry (GC/ MS) or Liquid Chromatography/Tandem Mass Spectrometry (LC/MS-MS) is the recommended confirmatory method.

Device Description

The Wondfo SAFElife™ Fentanyl Tests are immunoassays intended for the qualitative detection of fentanyl in human urine. Each Wondfo SAFElife™ Fentanyl Test consists of a Test Device in format of Cassette or Dip Card, and a package insert. Each Test Device is sealed with sachets of desiccant in an aluminum pouch.

AI/ML Overview

Acceptance Criteria & Study Analysis for SAFElife™ Fentanyl Urine Home Test

The SAFElife™ Fentanyl Urine Home Test (and its variants) are competitive binding, lateral flow immunochromatographic assays for qualitative detection of Fentanyl in human urine at a cutoff concentration of 1 ng/mL. The device provides preliminary test results, with confirmation requiring a more specific alternate chemical method like GC/MS or LC/MS-MS.

1. Acceptance Criteria and Reported Device Performance

The provided documentation does not explicitly state formal acceptance criteria in the typical "pass/fail" format for each performance characteristic. However, the study results implicitly demonstrate the device's acceptable performance based on standard expectations for qualitative drug screening tests.

Given the information, we can infer the acceptance criteria and compare them to the reported performance:

Acceptance Criteria (Inferred)	Reported Device Performance
Precision:	Cassette Precision:
Consistent results for samples significantly below and above the cutoff concentration.	-100% to -50% cutoff: All 50 tests across 3 lots were negative (50-/0+).
Acceptable performance around the cutoff, demonstrating the ability to differentiate positive and negative samples.	-25% cutoff: 46-48 negative, 2-4 positive across 3 lots.
	Cutoff (1 ng/mL): 23-28 positive, 22-27 negative across 3 lots.
	+25% to +100% cutoff: All 50 tests across 3 lots were positive (50+/0-).
	Dip Card Precision:
	-100% to -50% cutoff: All 50 tests across 3 lots were negative (50-/0+).
	-25% cutoff: 47-48 negative, 2-3 positive across 3 lots.
	Cutoff (1 ng/mL): 23-28 positive, 22-27 negative across 3 lots.
	+25% to +100% cutoff: All 50 tests across 3 lots were positive (50+/0-).
Stability:	The devices are stable at 36-86°F for 24 months based on accelerated stability study.
Interference:	Over 100 common substances (medications, endogenous compounds) showed no interference at specified concentrations (typically 100 µg/mL or physiological/pathological levels) when spiked into drug-free urine and fentanyl-positive urine (at -50% and +50% cutoff). This indicates a high level of specificity against a wide range of potential interferents.
No significant interference from common substances at physiological or therapeutic concentrations.
Specificity (Cross-Reactivity):	While some fentanyl analogs showed cross-reactivity (e.g., Acrylfentanyl, Isobutyryl fentanyl, Furanyl fentanyl at 100%; Butyryl fentanyl, Carfentanil at 50%), this is expected for drugs belonging to the same class or with similar chemical structures. Many other opioids (e.g., Morphine, Codeine, Buprenorphine, Oxycodone) and diverse compounds showed no cross-reactivity at 100 µg/mL, indicating good specificity against a broad range of other substances.
Acceptable cross-reactivity profile, with minimal false positives from unrelated compounds, and expected reactivity to close analogs.
Effect of Urine Specific Gravity & pH:	No differences in test results were observed across specific gravity ranges of 1.000 to 1.035 and pH ranges of 4 to 9. All samples at or above +50% Cut-Off were positive, and all samples at or below -50% Cut-Off were negative. This demonstrates robust performance across varying urine physiological conditions.
Robust performance across a physiologically relevant range of urine specific gravity and pH.
Method Comparison (Clinical Sample Performance):	Cassette: For 84 unaltered clinical samples (41 negative, 43 positive per LC/MS), typically 0 false positives for negative samples, 0-2 false negatives for high positive samples (with 1 false negative at 1.058 ng/mL, just over cutoff). A few "Near Cutoff Negative" (LC/MS between -50% and cutoff, i.e., 0.5-1 ng/mL) were reported positive by the rapid test, and some "Near Cutoff Positive" (LC/MS between cutoff and +50%, i.e., 1-1.5 ng/mL) were reported negative. The discordant results (e.g., sample 39 at 0.825 ng/mL, sample 41 at 0.914 ng/mL being positive) indicate reasonable performance near the cutoff.
High concordance with a confirmatory method (LC/MS) for both negative and positive samples, especially for samples well away from the cutoff.	Dip Card: Similar performance to the cassette. For 84 samples, typically 0 false positives for negative samples. A few false negatives for samples just above cutoff (e.g., 1.038 ng/mL, 1.015 ng/mL, 1.077 ng/mL). Discordant results (e.g., samples at 0.885, 0.914, 0.804, 0.825 ng/mL reported positive) demonstrate appropriate sensitivity around the cutoff. Overall, the method comparison shows acceptable agreement with LC/MS, particularly for samples clearly above or below the cutoff. The expected variation occurs in samples very close to the 1 ng/mL cutoff.
Lay-user Study:	Cassette & Dip Card: 100% correct results for samples well below (-100% to -50% cutoff) and well above (+25% to +75% cutoff). 95% correct results for -25% cutoff (0.7 ng/mL), with 1 out of 20 samples incorrectly read as positive. All lay users found instructions easy to follow, with a Flesch-Kincaid reading level below 7. This demonstrates the device's suitability for OTC (home) use.
High percentage of correct results by lay users, demonstrating ease of use and interpretation in a home setting.

2. Sample Size Used for the Test Set and Data Provenance

Precision Studies Test Set:
- For each of the 9 concentration levels, 50 tests were performed for each of the 3 device lots.
- Total tests for Precision (Cassette): 9 concentrations * 50 tests/concentration * 3 lots = 1350 tests.
- Total tests for Precision (Dip Card): 9 concentrations * 50 tests/concentration * 3 lots = 1350 tests.
- Data Provenance: The samples were "prepared by spiking fentanyl in negative samples." The document does not specify the country of origin but implies laboratory-prepared controlled samples. The study is prospective in nature as samples were prepared for the purpose of the study.
Interference Test Set: Not explicitly stated as a single "test set" size. "These urine samples were tested using three batches of each device." The number of samples for each interferent tested at specific concentrations (drug-free and fentanyl-spiked) is not quantified.
- Data Provenance: Laboratory-prepared controlled samples with spiked substances. Most likely retrospective analysis of prepared samples.
Specificity (Cross-Reactivity) Test Set: Similar to interference, not a single "test set" size. "drug metabolites and other components that are likely to interfere in urine samples were tested using three batches of device." The number of individual compounds tested is large (dozens of fentanyl analogs and many other opioids/non-opioids).
- Data Provenance: Laboratory-prepared controlled samples with spiked substances. Most likely retrospective analysis of prepared samples.
Effect of Urine Specific Gravity and pH Test Set: Not explicitly stated as a single "test set" size. "These samples were tested using three lots of device." Samples were prepared by spiking target fentanyl at -50% and +50% Cut-Off levels across specific gravity and pH ranges.
- Data Provenance: Laboratory-prepared controlled samples. Most likely retrospective analysis of prepared samples.
Method Comparison Studies Test Set:
- Cassette: 84 "unaltered clinical samples."
- Dip Card: 84 "unaltered clinical samples." (It's unclear if these are the same 84 samples for both formats or separate sets of 84).
- Data Provenance: "unaltered clinical samples." The country of origin is not specified, but the clinical nature suggests they were collected from human subjects. The study appears to be retrospective as these samples were "blind labeled" and then tested.
Lay-user Study Test Set:
- For each device format (Cassette and Dip Card), 7 different concentration levels were tested, with 20 samples per concentration.
- Total samples per device format: 7 concentrations * 20 samples/concentration = 140 samples.
- Total samples overall: 140 samples (Cassette) + 140 samples (Dip Card) = 280 samples.
- Data Provenance: Samples were "prepared at the following concentrations by spiking fentanyl into drug free-pooled urine specimens." The samples were then blind-labeled and randomized. The study is prospective since samples were prepared for the study.

3. Number of Experts Used to Establish the Ground Truth for the Test Set and Their Qualifications

Precision, Interference, Specificity, Effect of SG/pH, Lay-user Studies: The "ground truth" (actual fentanyl concentration or absence) was established by LC/MS (Liquid Chromatography/Mass Spectrometry) for all spiked samples. This is a highly accurate analytical method, and human experts are not directly establishing the ground truth in terms of visual interpretation for these studies. The LC/MS results are considered the definitive quantitative measurement.
Method Comparison Studies: The ground truth for the 84 "unaltered clinical samples" was established by LC/MS. The document states, "The samples were blind labeled and compared to LC/MS results." No human experts (e.g., pathologists, radiologists) were involved in establishing the ground truth for these quantitative drug levels.

4. Adjudication Method for the Test Set

The concept of "adjudication" (e.g., 2+1, 3+1) typically applies to situations where multiple human readers are interpreting results and their agreement/disagreement needs to be resolved. In this case, the device output is a qualitative (positive/negative) result based on a visual line, and the ground truth is established by a quantitative analytical method (LC/MS).

For the Precision studies, the results are quantitative counts of "positive" or "negative" for each lot and concentration, implying a direct read of the test.
For the Method Comparison Studies, the rapid test results from the operators were directly compared to the LC/MS results. Discordant results are simply listed. No adjudication process is described for resolving discrepancies in the rapid test readings themselves among different operators, but rather the discrepancy is noted between the rapid test result and the LC/MS ground truth.
For the Lay-user study, each participant (lay person) used one device and provided their result. The comparison was then made between the lay person's result and the LC/MS confirmed concentration. The study report only mentions "Lay person results" (No. of Positive / No. of Negative) implying their individual readings were collected and analyzed for correctness.

Therefore, an adjudication method in the traditional sense (e.g., expert panel review to resolve conflicting interpretations) was not applied, as the output is a qualitative visual reading compared to an analytical gold standard.

5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study was done

No, a Multi-Reader Multi-Case (MRMC) comparative effectiveness study was not done.

An MRMC study typically compares the performance of multiple human readers on multiple cases, often with and without AI assistance, to determine if the AI improves human reader performance (e.g., sensitivity, specificity, efficiency). The studies presented here focus on the standalone performance of the device itself (precision, analytical performance, and comparison to LC/MS) and a lay-user study for ease of use. There is no mention of human readers being compared with and without AI assistance.

6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) was done

Yes, the primary studies presented are essentially standalone performance studies for the device.

The SAFElife™ Fentanyl Urine Home Test is a qualitative lateral flow immunoassay. Its "algorithm" is the biochemical reaction that produces a visual line. The precision studies, interference studies, specificity studies, effect of SG/pH studies, and method comparison studies all evaluate the device's ability to correctly classify samples as positive or negative based on its inherent properties, without human interpretation being the primary variable of interest for method comparison against LC/MS.

While the "reading" of the line is ultimately done by a human (either a trained operator in the method comparison or a lay-user in that specific study), the performance characteristics described (e.g., sensitivity at cutoff, cross-reactivity) are intrinsic to the device's chemical and physical design, functioning as an "algorithm-only" or "device-only" performance evaluation against a gold standard. The lay-user study specifically tests the human-in-the-loop aspect for OTC use, but the core analytical performance is evaluated as standalone.

7. The Type of Ground Truth Used

The primary ground truth used across all analytical performance studies (Precision, Interference, Specificity, Effect of SG/pH, and Method Comparison) and the Lay-user study was Liquid Chromatography/Mass Spectrometry (LC/MS).

LC/MS is a highly sensitive and specific analytical technique used to identify and quantify substances in complex mixtures, making it a robust "gold standard" for determining precise drug concentrations in urine samples.

8. The Sample Size for the Training Set

The document does not describe a "training set" in the context of an algorithm that learns from data. This device is a biochemical immunoassay, not a software-based AI algorithm that requires a training phase. Its performance is determined by its physical and chemical design, not by learning from a dataset.

Therefore, the concept of a "training set" is not applicable to this device.

9. How the Ground Truth for the Training Set Was Established

As noted above, a "training set" is not applicable because this is a biochemical immunoassay, not a machine learning algorithm.

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