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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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Affirm One-Step home 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 over-the-counter home 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 along the membrane to the reagent pad where the hCG reacts with the conjugate. 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 an analysis of the provided text regarding the Affirm One-Step home pregnancy test, structured according to your request:

In this case, the acceptance criteria are largely implied rather than explicitly stated with numerical targets for specificity, sensitivity, and accuracy. The study aims to demonstrate that the device performs comparably to a predicate device and effectively detects hCG at a specified concentration.

1. Table of Acceptance Criteria and Reported Device Performance

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

• Specificity Test: The sample size is not explicitly stated as unique samples for LH, FSH, and TSH, but 25 mIU/ml hCG was tested simultaneously. It implies that at least one sample for each substance was tested.
• Sensitivity and Accuracy (Analytical): 20 negative urine samples were used, which were then "spiked with hCG at varying levels." This means 20 samples were tested at each concentration level: 10mIU/ml, 25mIU/ml, 50mIU/ml, 100mIU/ml, and 0mIU/ml.
• Interfering Substances: For each of the 8 interfering substances, samples were tested both with and without 25 mIU/ml hCG. The specific number of samples for each substance is not given, but it implies at least one sample for each condition.
• Predicate Device Result Correlation: 100 specimens.
• Data Provenance:
  • Analytical studies (Specificity, Sensitivity, Accuracy, Interfering Substances): The text does not explicitly state the country of origin but references "spiked" samples, indicating these were laboratory-controlled rather than collected from patients directly.
  • Predicate Device Result Correlation:
    • Country of Origin: Not explicitly stated, but "clinics around town" and "Planned Parenthood in either Southeast Portland or Beaverton" (Oregon, USA) suggest the data is from the United States.
    • Retrospective or Prospective: Prospective. The women were "solicited by a flyer" and asked to participate.

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

• Analytical Studies (Specificity, Sensitivity, Accuracy, Interfering Substances): For spiked samples (known concentrations of hCG, LH, FSH, TSH, and interfering substances), the "ground truth" is established by the laboratory's precise control over the spiked concentrations. No human experts are typically used to establish ground truth in this context; it's based on biochemical assays and measurements.
• Predicate Device Result Correlation: The ground truth for the 100 specimens (54 true positives and 46 true negatives) is implied to be established by the predicate device itself (SAS™ Pregnancy Strip), which is used as the reference test. No explicit number of experts or their qualifications are mentioned for establishing the "true positive" or "true negative" status of these clinical samples beyond the performance of the predicate device.

4. Adjudication Method for the Test Set

• None explicitly stated. For the analytical studies, the results are directly read from the device and compared to the known spiked concentrations. For the predicate device correlation, it's a direct comparison of the Affirm device's result to the SAS™ Pregnancy Strip's result for each specimen. There's no mention of multiple readers or an adjudication process for discrepancies.

5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done

• No. This type of study (MRMC) is not mentioned or described. The study focuses on the device's standalone performance and its comparison to a predicate device, not on how human readers' performance improves with or without AI assistance. This device is a home-use, over-the-counter diagnostic test, not a system designed to assist healthcare professionals in interpretations.

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

• Yes. The entire performance evaluation for the Affirm One-Step home pregnancy test is a standalone assessment. It's a consumer-use device where the user reads the visual result directly from the test strip without any "human-in-the-loop" decision support from an algorithm. The reported performance characteristics (specificity, sensitivity, accuracy, interference, and correlation study) all reflect the device's inherent capability to detect hCG.

7. The Type of Ground Truth Used

• Analytical Studies (Specificity, Sensitivity, Accuracy, Interfering Substances): Laboratory-controlled spiked concentrations of hCG and other substances. This represents a highly controlled, synthetic form of ground truth.
• Predicate Device Result Correlation: The results from the SAS™ Pregnancy Strip were used as the reference standard (ground truth) for the 100 clinical specimens.

8. The Sample Size for the Training Set

• This information is not provided in the summary. Pregnancy tests like this are typically developed through biochemical and immunoassay research and optimization, rather than machine learning models that require labeled training sets in the computational sense. The "training" would involve optimizing antibody concentrations, membrane types, and reaction conditions.

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

• This information is not provided as there isn't a conventional "training set" in the machine learning sense for this type of device. The development process would have involved establishing optimal performance characteristics through experimental design, using known concentrations of analytes (hCG, interfering substances) in the laboratory. The ground truth for this optimization would be based on the accurate measurement of these analytes in controlled laboratory settings.

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