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Affirm One-Step Professional Pregnancy Test is a rapid one-step visual test for the qualitative detection of human Chorionic Gonadotropin in human urine to aid in the diagnosis of pregnancy. This test is intended for Professional use.

Affirm detects the presence of hCG in urine by using a combination of polyclonal and monoclonal antibodies on the reagent pad and the test strip. The assay begins functioning with the addition of urine onto the absorbent wick. Through capillary action the urine is pulled to the reagent pad where the hCG reacts with the conjugate, and then through the membrane containing bound capture antibodies. Positive results are determined by one color line in the test window and one color line in the control window. The absence of hCG produces only one color line in the control window.

Here's a breakdown of the acceptance criteria and study information for the Affirm One-Step Professional Pregnancy Test, based on the provided text:

Acceptance Criteria and Device Performance

Study Information

2. Sample size used for the test set and the data provenance (e.g. country of origin of the data, retrospective or prospective)

• Sensitivity/Specificity Test Set:
  • Sample Size: 20 negative urine samples for sensitivity testing, and additional samples for cross-reactivity/inhibition (number not specified but implied to be sufficient for testing against LH, FSH, TSH, and spiked hCG samples).
  • Data Provenance: Not explicitly stated, but implied to be a laboratory-controlled study using spiked urine samples. Country of origin not specified. Retrospective (samples were prepared/spiked for testing).
• User/Laboratory Accuracy Test Set (Comparison with Predicate Device):
  • Sample Size: 104 specimens
  • Data Provenance: Women participating in the study were solicited by a flyer in clinics locally, and participated at Athena Medical Corporation, Planned Parenthood in Southeast Portland or Beaverton, Oregon. This indicates prospective data collection within the USA.

3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts (e.g. radiologist with 10 years of experience)

• Sensitivity/Specificity: Ground truth was established by spiking known concentrations of hCG into negative urine samples. Therefore, no human experts were required to establish ground truth in the traditional sense; the ground truth was inherent in the controlled spiking.
• User/Laboratory Accuracy: The text doesn't specify how the "true positives" and "true negatives" were definitively established for the 104 specimens used in the accuracy correlation study. It mentions the SAS™ Pregnancy Strip identified 54 true positives and 46 true negatives, implying this predicate device's results were used as a reference for laboratory accuracy. For the "user accuracy," women participants identified the results, and these were then presumably compared to a referencestandard. It's unclear if a separate "expert" confirmation (e.g., blood tests, clinical diagnosis) was used to define the absolute ground truth for pregnancy status.

4. Adjudication method (e.g. 2+1, 3+1, none) for the test set

• The text does not describe an adjudication method for the test sets. For the sensitivity/specificity, results were direct readings of the device against known spiked concentrations. For the user/laboratory accuracy, direct comparisons were made, and it's not clear if discrepancies beyond the 1 false negative were subjected to adjudication.

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 conducted. This device is a rapid diagnostic test, not an AI-assisted diagnostic tool for interpretation by multiple human readers. The comparative study was between the new device and a predicate device, and also included "user accuracy" where individual users interpreted the test.

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

• Yes, the performance characteristics (sensitivity, specificity, interfering substances) represent the standalone performance of the device without human-in-the-loop interpretation being the primary variable. The "user accuracy" section does involve human interpretation, but the core performance criteria are about the device's inherent ability to detect hCG. The device itself is designed for visual interpretation.

7. The type of ground truth used (expert consensus, pathology, outcomes data, etc)

• Sensitivity/Specificity: Spiked samples/Known concentrations. Ground truth was established by artificially creating urine samples with precise, known concentrations of hCG and other substances.
• User/Laboratory Accuracy: The ground truth for pregnancy status appears to have been established primarily by comparison with a predicate device (SAS™ Pregnancy Strip) for the laboratory aspect. For user accuracy, while user input was collected, the ultimate "true positive" and "true negative" labels likely stemmed from this predicate device comparison or another clinical reference standard not explicitly detailed in the summary.

8. The sample size for the training set

• This device is a lateral flow immunoassay, not an AI/machine learning algorithm. Therefore, there is no "training set" in the context of algorithmic development. The development process would involve formulation and optimization of reagents and design rather than data training.

9. How the ground truth for the training set was established

• As there is no training set for an AI/machine learning algorithm, this question is not applicable.

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