(76 days)
The UniMark™ Midstream Pregnancy Test Stick is intended for the qualitative measurement of human chorionic gonadotropin (hCG) in urine as a home use screening test for pregnancy.
The UniMark™ Midstream Pregnancy Test Stick is a home use, rapid, visual, one step screening test for pregnancy. UniMark™ is a colored solid-phase immunoassay for qualitative detection of elevated levels of hCG in urine for the early pregnancy diagnosis. It is based on a two-site sandwich immunometric assay which utilizes a unique combination of monoclonal and polyclonal antibodies to selectively identify hCG with a high degree of sensitivity. UniMark™ contains a strip with a sample pad and a membrane area. The former contains mouse anti-hCG monoclonal antibody conjugated with colloid gold. The latter is coated with goat anti-mouse IgG at the control zone and goat anti-hCG antibody at the test zone. During the test, the urine is sucked up through sample pad by capillary action, and hCG in the urine sample binds to the gold conjugate, moving chromatographically toward the membrane. The immobilized goat anti-hCG antibody at the test zone catches the resulting complexes, forming an antibody-hCG-gold conjugate complex. The appearance of a purple band in the test window resulted from the complex shows a positive result, which indicates presence of hCG and suggests a pregnancy. Absence of this band, on the other hand, displays a negative result, i.e. no detectable hCG in the urine sample. The appearing of a purple band in the control window demonstrates proper performance and validity of the reactive reagent.
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1. Table of Acceptance Criteria and Reported Device Performance
| Acceptance Criteria | Reported Device Performance (UniMark™) |
|---|---|
| Sensitivity | 25 mIU/ml or greater |
| Accuracy | >99% |
| Specificity | No interferences (from hLH, hFSH, hTSH) |
Detailed Performance Breakdown:
Non-Clinical Tests:
- Sensitivity:
- 0 mIU/ml hCG: 100% negative (3 lots tested)
- 20 mIU/ml hCG: 95% negative, 5% positive (3 lots tested) - Note: This indicates some border-line detection at 20 mIU/ml, but full positive detection is at 25 mIU/ml.
- 25 mIU/ml hCG: 100% positive (3 lots tested)
- 50 mIU/ml hCG: 100% positive (3 lots tested)
- 100 mIU/ml hCG: 100% positive (3 lots tested)
- Specificity (Interference Studies):
- hLH: No interference observed at 10, 100, 200 mIU/ml hLH. The device remained positive when 25 mIU/ml hCG was added to these hLH concentrations.
- hFSH: No interference observed at 1000 mIU/ml hFSH. The device remained positive when 25 mIU/ml hCG was added.
- hTSH: No interference observed at 1000 uIU/ml hTSH. The device remained positive when 25 mIU/ml hCG was added.
Clinical Tests:
- Correlation with CIDA Professional Test (Reference Standard): 100% correlation with UniMark™ home user results.
- UniMark™ Positive / CIDA Positive: 119 cases
- UniMark™ Negative / CIDA Negative: 27 cases
- Total cases: 146
2. Sample Size Used for the Test Set and Data Provenance
- Sample Size (Clinical Test Set): 146 home users.
- Data Provenance: Prospective, from a women's center in southern New Jersey, USA.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of those Experts
- Number of Experts: At least two for the clinical portion:
- "The user test results were observed and verified by the lab assistant (to verify correct interpretation of positive or negative)."
- The "CIDA professional test results" imply a professional lab test was used as the ground truth, likely interpreted by qualified lab personnel, though their specific qualifications are not detailed beyond "professional test."
- Qualifications of Experts: The text states "lab assistant" and "CIDA professional test results." Specific qualifications (e.g., years of experience, certification) are not provided for either.
4. Adjudication Method for the Test Set
- Clinical Test Set: The text indicates that the home user's interpretations were "observed and verified by the lab assistant." This suggests a form of 1:1 verification, where the lab assistant confirmed the user's reading. The "CIDA professional test" was then used as the definitive ground truth against which both the home user's interpretation and the lab assistant's verification would presumably align or be compared. It implies a direct comparison rather than a formal voting/adjudication process like 2+1 or 3+1 among multiple human readers of the device itself.
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
- MRMC Study: No, an MRMC comparative effectiveness study was not conducted. This device is a standalone home-use test, and the study evaluated its performance against a professional lab test, not the improvement of human readers with AI assistance.
6. If a Standalone (i.e. algorithm only without human-in-the loop performance) was done
- Standalone Performance: Yes, the entire study effectively evaluates the standalone performance of the UniMark™ device itself. Both the non-clinical (sensitivity, specificity) and clinical (correlation with CIDA) tests assess the device's ability to accurately detect hCG without human interpretive intervention beyond observing the colored bands. The "home user" aspect tests the device usability and interpretability by a layperson, but the underlying performance is that of the device.
7. The Type of Ground Truth Used
- Clinical Test Set: The primary ground truth for the clinical study was the CIDA professional test results. This represents a laboratory reference standard.
- Non-Clinical Test Set: The ground truth for sensitivity and specificity was known concentrations of hCG, hLH, hFSH, and hTSH (prepared according to WHO standards).
8. The Sample Size for the Training Set
- The document describes performance data for the UniMark™ device, which is a chemical/immunological test kit. It does not employ an AI algorithm or machine learning model, and therefore, there is no training set in the context of AI development. The device relies on pre-determined biochemical reactions.
9. How the Ground Truth for the Training Set Was Established
- As stated in point 8, there is no training set for this type of 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.