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First Sign Drug of Abuse MDMA Tests are immunoassay tests. The test can detect MDMA in human urine. The cut-off value is 500 ng/mL.. The tests are available in a Cup format and a Dip Card format.

The tests provide only preliminary test results. If you want to get a confirmed result, you must use a more specific chemical method. Gas Chromatography/Mass Spectrometry is the preferred confirmatory method. Clinical consideration and professional judgment should be used when you get any drug of abuse test result. It should be used particularly when the preliminary result is positive.

For in vitro diagnostic use only. The tests are intended for over-the-counter and for prescription use.

First Sign Drug of Abuse EDDP Tests are immunoassay tests. The test can detect EDDP in human urine. The cut-off value is 300 ng/mL. The tests are available in a Cup format and a Dip Card format.

The tests provide only preliminary test results. If you want to get a confirmed result, you must use a more specific chemical method. Gas Chromatography/Mass Spectrometry is the preferred confirmatory method. Clinical consideration and professional judgment should be used when you get any drug of abuse test result. It should be used particularly when the preliminary result is positive.

For in vitro diagnostic use only. The tests are intended for over-the-counter and for prescription use.

First Sign Drug of Abuse Nortriptyline Tests are immunoassay tests. The test can detect Nortriptyline in human urine. The cut-off value is 1,000 ng/mL. The tests are available in a Cup format and a Dip Card format.

The tests provide only preliminary test results. If you want to get a confirmed result, you must use a more specific chemical method. Gas Chromatography/Mass Spectrometry is the preferred confirmatory method. Clinical consideration and professional judgment should be used when you get any drug of abuse test result. It should be used particularly when the preliminary result is positive.

For in vitro diagnostic use only. The tests are intended for over-the-counter and for prescription use.

First Sign™ Drug of Abuse MDMA Test, First Sign™ Drug of Abuse EDDP Test and First Sign™ Drug of Abuse Nortriptyline Test are immunochromatographic assays. Each assay test is a lateral flow system for the qualitative detection of MDMA, or EDDP or Nortriptyline in human urine. The products are single-use in vitro diagnostic devices, which come in the formats of Dip Cards or Cups. Each test kit contains a Test Device (in one of the two formats), a package insert and a urine cup for sample collection. Each test device is sealed with a desiccant in an aluminum pouch.

The provided document describes the performance characteristics of three drug of abuse tests: First Sign® Drug of Abuse MDMA Test, First Sign® Drug of Abuse EDDP Test, and First Sign® Drug of Abuse Nortriptyline Test. These are qualitative immunoassay tests designed to detect specific drugs in human urine.

Here's an analysis of the acceptance criteria and study details:

1. Table of Acceptance Criteria and Reported Device Performance

The document does not explicitly state formal acceptance criteria thresholds in terms of specific percentages for accuracy, sensitivity, or specificity. However, the performance is reported through various studies, and the implied acceptance criteria are that the device performs reliably at and around the defined cut-off values, and that lay users can operate the device effectively.

Below is a table summarizing the reported device performance, categorized by drug:

First Sign® Drug of Abuse MDMA Test

First Sign® Drug of Abuse EDDP Test

First Sign® Drug of Abuse Nortriptyline Test

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

• Precision Studies:

  • For each drug (MDMA, EDDP, Nortriptyline) and each format (Cup, Dip Card): 9 concentration levels (from -100% cut-off to +100% cut-off).
  • At each concentration level: 50 tests (2 runs/day for 25 days).
  • Total for precision per drug/format: 9 concentrations * 50 tests/concentration = 450 tests.
  • Total for precision across all 3 drugs and 2 formats: 3 * 2 * 450 = 2700 tests.
  • Data Provenance: "Prepared by spiking drug in negative urine samples." This suggests laboratory-controlled samples, likely from a US lab given the FDA submission. Retrospective, as samples were prepared and then tested.

• Cut-off Verification Studies:

  • For each drug and format: 4 concentration levels ( -50% cut-off, cut-off, +25% cut-off, +50% cut-off).
  • Total of 150 samples "equally distributed" meaning approximately 37-38 samples per concentration level. These were tested using three different lots.
  • Data Provenance: Laboratory-controlled samples, likely from a US lab. Retrospective.

• Interference and Specificity Studies:

  • The document implies that these were conducted with spiked samples in drug-free urine, testing against three lots of each device for all formats. No specific sample numbers are given for individual interference compounds or cross-reactants, but the method suggests a systematic laboratory study.
  • Data Provenance: Laboratory-controlled samples, likely from a US lab. Retrospective.

• Effect of Urine Specific Gravity and Urine pH:

  • Urine samples with varying specific gravity and pH were spiked with target drugs at 25% below and 25% above cut-off levels. Tested using three lots of each device for all formats. No specific sample number provided, but implies a comprehensive set to cover the specified ranges.
  • Data Provenance: Laboratory-controlled samples, likely from a US lab. Retrospective.

• Comparison Studies (Clinical Samples):

  • For each drug and each format: 80 unaltered clinical samples (40 negative, 40 positive).
  • Total for comparison studies across all 3 drugs and 2 formats: 3 * 2 * 80 = 480 clinical samples.
  • Data Provenance: "Unaltered clinical samples" implies real human urine samples from an unspecified source (likely US-based for FDA submission). The study is retrospective, as samples were collected and then tested.

• Lay-User Study:

  • For each drug: 280 lay persons.
  • Each participant tested one blind-labeled urine sample. There were 7 concentration levels tested (-100%, -75%, -50%, -25%, +25%, +50%, +75% of cut-off).
  • For each concentration and format (Dip Card / Cup): 20 samples.
  • Total samples given to lay users per drug: 7 concentrations * 20 samples/concentration * 2 formats = 280 samples. This matches the 280 lay persons.
  • Data Provenance: Laboratory-prepared urine samples (spiked drug into drug-free pooled urine). This is a prospective simulation of real-world use with prepared samples. The study was performed at "three intended user sites". Given the FDA submission, these are likely US sites.

3. Number of Experts and Qualifications for Ground Truth

• Precision, Cut-off, Interference, Specificity, Urine SG/pH Studies:

  • The ground truth (drug concentration) for all these studies was established by GC/MS (Gas Chromatography/Mass Spectrometry). This is a highly accurate and widely accepted reference method for drug quantification in toxicology. The document does not specify a separate "expert" for interpreting GC/MS results, as the instrument provides quantitative values which are then used to prepare samples.

• Comparison Studies (Clinical Samples):

  • The ground truth for the 80 clinical samples per drug/format was established by GC/MS results.
  • The device results were interpreted by three different laboratory assistants. Their qualifications are not explicitly stated beyond "laboratory assistants," but it can be inferred they are trained professionals in a laboratory setting.

• Lay-User Study:

  • The ground truth for the prepared urine samples was established by GC/MS to confirm the spiked drug concentrations.
  • No "experts" were used to establish ground truth for how the lay users interpreted the test, as the study's purpose was to evaluate if lay users could correctly interpret the device results against the known (GC/MS confirmed) concentration.

4. Adjudication Method for the Test Set

• Precision Studies, Cut-off Verification, Interference, Specificity, Urine SG/pH Studies: The ground truth used was quantitative GC/MS results, which serves as a definitive reference standard. There's no indication of an adjudication process among multiple readers for these lab-controlled tests; the output of the device (positive/negative line) was compared directly to the GC/MS confirmed concentration.

• Comparison Studies (Clinical Samples): The document mentions "three different laboratory assistants" running the tests and comparing them to GC/MS results. It does not describe an adjudication method (like 2+1 or 3+1) among these three assistants where they would resolve discrepancies in their readings. Instead, individual discrepancies are noted in the "Discordant Results" tables for each viewer. This suggests independent assessment rather than a consensus-seeking or adjudicated process for the readers.

• Lay-User Study: Each lay user interpreted their own test result individually against the known GC/MS confirmed concentration. No adjudication among lay users was described.

5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study

• No, a typical MRMC comparative effectiveness study was not explicitly conducted as described for AI vs. human readers.
• The comparison studies did involve multiple readers (three laboratory assistants) reviewing clinical cases, which provides some multi-reader data. However, this was a standalone performance evaluation of the device being read by humans, not a comparison of human performance with vs. without AI assistance. The device itself is an immunoassay, not an AI algorithm providing assistance in interpreting complex images or data.
• Therefore, an "effect size of how much human readers improve with AI vs without AI assistance" is not applicable here.

6. Standalone (Algorithm Only) Performance

• Yes, in essence, the "Analytical Performance" section (Precision, Cut-off, Interference, Specificity) represents the standalone performance of the devices. These studies evaluate the intrinsic performance of the immunoassay devices under controlled laboratory conditions, without human interpretation variability, by comparing the device's qualitative output (presence/absence of lines) against known, quantitatively confirmed drug concentrations.
• The "Comparison Studies" with laboratory assistants and "Lay-user studies" then evaluate the human-in-the-loop performance.

7. Type of Ground Truth Used

• All studies (Analytical, Comparison, Lay-User) consistently used Gas Chromatography/Mass Spectrometry (GC/MS) results as the gold standard ground truth.
• GC/MS is a laboratory-based, highly accurate, and quantitative method for identifying and measuring specific substances in a sample, making it a robust ground truth for drug testing.

8. Sample Size for the Training Set

• Not applicable. These are immunoassay devices (lateral flow tests), not machine learning or AI algorithms that require a "training set." The performance characteristics are derived from intrinsic chemical and physical properties, evaluated through these detailed analytical and clinical studies.

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

• Not applicable, as no training set was used.

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