(68 days)
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
| Acceptance Criteria Category | Acceptance Criteria | Reported Device Performance |
|---|---|---|
| Sensitivity | Detects hCG as low as 25 mIU/ml | All 20 samples spiked at 25 mIU/ml generated a positive reading within 4 minutes. (5/20 at 10 mIU/ml positive after ~15 min) |
| Specificity | No cross-reactivity with LH (300 mIU/ml), FSH (1000 mlU/ml), and TSH (1000 ulU/ml). No inhibition of 25 mIU/ml hCG by these substances. | Affirm did not cross-react with LH, FSH, or TSH at the specified levels. Samples spiked with 25 mIU/ml hCG were not inhibited by these substances. |
| Interference | No interference from specified substances (Acetaminophen, Acetylsalicylic Acid, Ascorbic Acid, Atropine, Caffeine, Gentisic Acid, Glucose, Hemoglobin) | No interference reported for any of the listed substances at their specified concentrations. |
| User Accuracy | Not explicitly stated as an "acceptance criteria" but evaluated against the predicate device. | 99% user accuracy rate (53 true positives, 46 true negatives, 1 false negative) |
| Laboratory Accuracy | Not explicitly stated as an "acceptance criteria" but evaluated against the predicate device. | 100% laboratory accuracy rate using the predicate device (54 true positives, 46 true negatives) |
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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K964574
Jan. 21, 1997
510 (k) SUMMARY
AFFIRM ONE STEP PROFESSIONAL PREGNANCY TEST
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510(k) Summary
Athena Medical Corporation
10180 SW Nimbus Ave. Suite J-5 Portland, OR 97223
Patricia Feetham
Phone: 503/968-8800 ext. 19
Fax: 503/639-3674 Proprietary Name: Product Name: Affirm One-Step Professional Pregnancy Test Classification Name: human Chorionic Gonadotropin test systems 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. Description of Device: 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.
Predicate device for substantial equivalence comparison:
Date Prepared:
Submitted by:
Intended Use:
Contact:
SAS™ Pregnancy Strip
November 1, 1996
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Substantial Equivalence:
Comparison Product: SAS™ Pregnancy Strip SA Scientific™ Scientific™
4919 Golden Quail Manufactured by: San Antonio TX 78240
Similarities to SAS™ Pregnancy Strip:
| Items to be compared | Affirm One-Step ProfessionalPregnancy Test | SAST™ Pregnancy Strip |
|---|---|---|
| • Detection method: | hCG in urine specimens reactswith the colored-conjugate on thepad producing a solid color (red)line in the test region. Mouseconjugate binds to goat anti-mouseantibody in the control region onthe strip. | hCG in urine specimens reactswith the colored-conjugate on thepad producing a solid color (red)line in the test region. Mouseconjugate binds to goat anti-mouseantibody in the control region onthe strip. |
| • Method | Mid-stream or dip. | Dip only. |
| • Usage: | Anytime of the day. | Anytime of the day. |
| • Pregnancy determination: | As early as the first day of awomen's missed period. | As early as the first day of awomen's missed period. |
| • Antibodies: | Polyclonal goat anti-alpha hCGantibody is on the test strip,monoclonal anti-beta hCGantibody is on the conjugate pad,and polyclonal goat anti-mouseIgG antibody is on the control line. | Polyclonal goat anti-alpha hCGantibody is on the test strip,monoclonal anti-beta hCGantibody is on the conjugate pad,and polyclonal goat anti-mouseIgG antibody is on the control line. |
| • Results: | Positive = color line in testwindow and control window.Negative = color line in controlwindow only. | Positive = color line in specimenzone and control zone.Negative = color line in controlzone only. |
| • Format: | Lateral Flow assay. | Lateral Flow assay. |
| • Sensitivity: | Detects level of hCG as low as25 mIU/ml. | Detects level of hCG as low as25 mIU/ml. |
| • Device design: | Slender, pen-like shape, removablecap, absorbent tip partiallyenclosed, two window result view. | Test strip utilizing an immersionzone, a specimen zone and controlzone. |
| • Visual detection: | A solid color line appears incontrol and test window in thepresence of hCG.A solid color line appears in thecontrol window only in theabsence of hCG. | A solid color band appears inspecimen and control zones in thepresence of hCG.A solid color band appears in thecontrol zone only in the absence ofhCG. |
| Items to be compared | Affirm One-Step Professionalpregnancy test | SAST™ Pregnancy Strip |
| • Device engineering: | Test device which contains anexposed absorbent wick, aconjugate pad, nitrocellulosemembrane containing boundantibodies, and a wicking pad ina disposable plastic container.Result windows and two "teardrop" openings exposing theabsorbent wick appear on thesame side of the device. Areacovering wick is a small cap.Result and control windowsinclude a moisture resistant clearbarrier. | Test strip only, which contains anexposed absorbent wick, aconjugate pad, nitrocellulosemembrane containing boundantibodies, and a wicking pad.Test strips are stored in adesiccated canister until ready foruse. |
| • Developing time: | Minimum of 4 minutes fornegative results to appear;positive results as soon as 1 - 2minutes (see Appendix A).Maximum of 20 minutes for anyresult. | Read results after 5 minutes. Donot interpret results after 30minutes. |
| • Absorbent wick: | Partially enclosed with 2 tear dropopenings in the plastic housing. | Wick is bottom 1/3 of test strip. |
| • Results windows: | Covered by a clear plastic shieldwhich acts as splash guard toprotect the results. | Colored bands are displayed inthe specimen and/or control zoneon the strip. |
| • Test window/Control window: | Test window shape is: "+".control window shape is: "O". | Test zones are bands in themiddle to upper quadrant of thetest strip. |
| • Color of holder: | Ivory | No holder |
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The differences between the Affirm One-Step Professional Pregnancy Test and SASTM Pregnancy Strip are not significant and do not effect the safety and effectiveness of the device.
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Performance characteristics:
Specificity:
Affirm One-Step Professional Pregnancy Test was evaluated for specificity against LH (300 mIU/ml), FSH (1000 mlU/ml), and TSH (1000 ulU/ml. Affirm did not cross-react with these substances at these levels, nor were samples spiked with 25 mIU/ml concentration of hCG inhibited by these substances.
Sensitivity:
The sensitivity of the Affirm One-Step Professional Pregnancy Test was determined using 20 negative urine samples spiked with hCG at varying levels. The results are described in the table below.
| ConcentrationSpiked at: | Results: Positive | Results: Negative |
|---|---|---|
| 10 mIU/ml | 5 | 15 |
| 25 mIU/ml | 20 | 0 |
| 50 mIU/ml | 20 | 0 |
| 100 mIU/ml | 20 | 0 |
| 0 mIU/ml | 0 | 20 |
Sensitivity of Affirm One-Step Professional Pregnancy Test:
Of the 20 samples that were tested at the 10 mIU/ml concentration, 5 of them generated a positive reading after about 15 minutes from the point of sauration. The 20 samples tested at the 25 mIU/ml concentration all generated a positive reading within 4 minutes. Therefore our claim is a 25 mIU/ml sensitivity with the Affirm One-Step Professional Pregnancy Test. Even though the test is sensitive enough to read concentrations lower than 25 mIU/ml this does not occur regularly for us to claim a lower sensitivity for the test.
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Interfering Substances:
The following potentially interfering substances were added to hCG negative and 25 mIU/ml hCG spiked urine samples. Interfering test samples were compared directly to the control result. The following results are described in the table below:
| Substance: | Concentration: | Interference: |
|---|---|---|
| Acetaminophen | 20 mg/dl | NONE |
| Acetylsalicylic Acid | 20 mg/dl | NONE |
| Ascorbic Acid | 20 mg/dl | NONE |
| Atropine | 20 mg/dl | NONE |
| Caffeine | 20 mg/dl | NONE |
| Gentisic Acid | 20 mg/dl | NONE |
| Glucose | 2 g/dl | NONE |
| Hemoglobin | 200 mg/dl | NONE |
Interference of the Affirm One-Step Professional Pregnancy Test
Predicate Device Accuracy Correlation:
One hundred and four specimens were evaluated by the urine stream method and the dir method. The women participating in the study were solicited by a flyer appearing in clinics locally, and asked to participate at one of the following locations: Athena Medical Corporation, Planned Parenthood in either Southeast Portland or Beaverton, Oregon. Women who participated in the urine stream method answered a questionnaire about the product. The women participants identified 53 true positives and 46 true negatives, with 1 false negative, generating a 99% user accuracy rate for the Affirm One-Step Professional Pregnancy Test. The laboratory comparison of the same collected samples using the SAS™ Pregnancy Strip identified 54 true positives and 46 true negatives, generating a 100% laboratory accuracy rate. There were four invalid results due to insufficient urine placed on the device.
§ 862.1155 Human chorionic gonadotropin (HCG) test system.
(a)
Human chorionic gonadotropin (HCG) test system intended for the early detection of pregnancy —(1)Identification. A human chorionic gonadotropin (HCG) test system is a device intended for the early detection of pregnancy is intended to measure HCG, a placental hormone, in plasma or urine.(2)
Classification. Class II.(b)
Human chorionic gonadotropin (HCG) test system intended for any uses other than early detection of pregnancy —(1)Identification. A human chorionic goadotropin (HCG) test system is a device intended for any uses other than early detection of pregnancy (such as an aid in the diagnosis, prognosis, and management of treatment of persons with certain tumors or carcinomas) is intended to measure HCG, a placental hormone, in plasma or urine.(2)
Classification. Class III.(3)
Date PMA or notice of completion of a PDP is required. As of the enactment date of the amendments, May 28, 1976, an approval under section 515 of the act is required before the device described in paragraph (b)(1) may be commercially distributed. See § 862.3.