(48 days)
The Pregnancy-Skreen™ controls are intended to validate the performance of qualitative hCG urine procedures and immunochromatographic devices.
The Biochemical Diagnostics, Inc., Pregnancy-Skreen™ urine controls are intended to validate the performance of qualitative hCG methods. They should be used as an external quality control to monitor the performance of the "specimen while following the specific protocol of the assay being used. This product is intended to be used by health care professionals as an integral part of good laboratory practices.
These products are manufactured in a liquid matrix solution prepared with negative human urine, chemicals, and preservatives. The matrix is not known to interfere with any immunoassay procedures including those used in handheld devices. The positive control is spiked in a target range of 200-400 mIU of Human Chorionic Gonadotropin per mL of urine.
Here's a summary of the acceptance criteria and the study that proves the device meets the acceptance criteria for the Pregnancy-Skreen™ hCG Liquid Control Urine, based on the provided text:
Device: Pregnancy-Skreen™ hCG Liquid Control Urine - Positive and Negative
1. Table of Acceptance Criteria and Reported Device Performance
| Acceptance Criteria | Reported Device Performance |
|---|---|
| Performance Validation (Substantial Equivalence): Controls should perform as expected when tested against predicate devices and on target diagnostic devices. | All controls performed as expected with positive controls reading positive and negative controls reading negative when tested side-by-side with predicate controls (Biorad Liquichek (K965171, K031231) and qUAntity urine controls (K042446)) on three elevated hCG diagnostic test devices (Unotech Accutest (K971886), Quidel Card QS (K972748), and Quickvue (K020799)). |
| New Lot Performance: New lots of material must perform comparably to released lots and other existing controls in the market. | New lots are stated to be run against released lots and other existing controls, implying comparable performance. (Specific data for new lots not detailed, but the acceptance states they perform as expected). |
| Room Temperature Stability (Accelerated Testing): Controls stored at room temperature (18-25°C) should maintain performance and show no cloudiness (indicating contamination). | Unopened controls were stable for at least 31 days (limit of study) when stored at room temperature (18-25°C). The testing serves to check for cloudiness. Opened controls were stable for at least 31 days when stored at room temperature (18-25°C). |
| Refrigerated Stability: Controls stored refrigerated at 2-8°C should maintain performance over a specified period. | Unopened controls were stable for two years when stored refrigerated at 2-8°C. Opened controls, when sampled by pouring (not pipetting) were stable for two years when stored at 2-8°C. |
| Qualitative Result Consistency: Positive controls should consistently read positive, and negative controls should consistently read negative. | During stability testing across various lots, identical qualitative results (positive or negative) were observed as the long-term test lot. All controls performed as expected (positive controls positive, negative controls negative). |
| Matrix Integrity: The liquid matrix solution should not interfere with immunoassay procedures. | The matrix is described as "not known to interfere with any immunoassay procedures." (This is more of a characteristic assertion than a tested criterion, but it's part of the device description). |
| Preservative Efficacy: Preservatives (Sodium Azide) should prevent contamination without exceeding specified concentrations. | Controls contain Sodium Azide in a concentration less than 0.1%, with a statement of being effective. (Implied efficacy through stability and absence of cloudiness observations). |
2. Sample Size Used for the Test Set and Data Provenance
- Sample Size for Test Set: The exact number of individual control units or tests performed is not explicitly stated as a single "sample size." However, the study involved:
- Testing the negative and positive Pregnancy-Skreen™ controls (presumably multiple units/aliquots) "from date of manufacture to date of expiration."
- Side-by-side testing with two predicate Biorad controls (Liquichek and qUAntity).
- Testing on three different hCG diagnostic test devices (Unotech Accutest, Quidel Card QS, and Quickvue).
- Stability testing across multiple lots (including a single long-term lot over two years, and "several other lots" tested periodically). Aliquots were sampled bi-weekly for unopened stability and an unspecified frequency for opened stability.
- Data Provenance: Retrospective (though the ongoing stability testing and customer surveys have prospective elements for continuous monitoring). The data was generated by the manufacturer, Biochemical Diagnostics, Inc., in the USA (Edgewood, NY).
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications
This device is a quality control material, not a diagnostic test being evaluated for accuracy against a clinical ground truth. Therefore, the concept of "experts establishing ground truth" in the traditional sense (e.g., radiologists interpreting images) does not directly apply here.
The "ground truth" for the controls themselves is inherent in their formulation:
- The negative control is prepared with negative human urine, meaning it should inherently test negative for hCG.
- The positive control is spiked with hCG in a target range of 200-400 mIU/mL, meaning it should inherently test positive for hCG within assays sensitive to this range.
The "experts" involved would be the quality control and R&D personnel at Biochemical Diagnostics, Inc. who formulated these controls and designed the testing protocols. Their qualifications would likely include expertise in immunoassay development, quality control, and analytical chemistry, but specific credentials are not provided.
4. Adjudication Method for the Test Set
No formal adjudication method (e.g., 2+1, 3+1) was described because the primary assessment for quality control materials is whether they perform as expected on established qualitative assays. The "ground truth" is known by design (negative control contains no hCG, positive control contains hCG). The observation is a simple qualitative 'positive' or 'negative' result from the assay.
The study simply states, "All controls performed as expected with positive controls reading positive and negative controls reading negative." This indicates direct observation of assay results against the known expected outcome for each control.
5. If a Multi Reader Multi Case (MRMC) Comparative Effectiveness Study Was Done
No. An MRMC study is typically used for diagnostic imaging or interpretation devices where human readers evaluate cases with and without AI assistance. This device is a quality control material for in vitro diagnostic tests, not a diagnostic test itself, and does not involve human reader interpretation. Therefore, no MRMC study was conducted, and no effect size for human reader improvement is applicable.
6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) Was Done
The device itself is a reagent (control material), not an algorithm or an automated system. Its "performance" is its ability to elicit the expected positive or negative result when run on a diagnostic test device. The study evaluated this standalone performance of the control material using existing diagnostic test devices. There is no "human-in-the-loop" concept for the control material itself; rather, it's used by humans (laboratory professionals) to validate other diagnostic tests.
7. The Type of Ground Truth Used
The ground truth used is primarily design-based or manufactured ground truth:
- Negative Control: Composed of human urine confirmed to be negative for hCG.
- Positive Control: Human urine matrix spiked with a known concentration of hCG (200-400 mIU/mL).
This is a form of analytical ground truth, where the composition and expected behavior of the control material are known parameters established during its formulation.
8. The Sample Size for the Training Set
This question is not applicable. The Pregnancy-Skreen™ is a quality control material, not an AI or machine learning algorithm. Therefore, there is no "training set" in the context of model development.
9. How the Ground Truth for the Training Set Was Established
This question is not applicable, as there is no training set for this type of device.
§ 862.1660 Quality control material (assayed and unassayed).
(a)
Identification. A quality control material (assayed and unassayed) for clinical chemistry is a device intended for medical purposes for use in a test system to estimate test precision and to detect systematic analytical deviations that may arise from reagent or analytical instrument variation. A quality control material (assayed and unassayed) may be used for proficiency testing in interlaboratory surveys. This generic type of device includes controls (assayed and unassayed) for blood gases, electrolytes, enzymes, multianalytes (all kinds), single (specified) analytes, or urinalysis controls.(b)
Classification. Class I (general controls). Except when intended for use in donor screening tests, quality control materials (assayed and unassayed) are exempt from the premarket notification procedures in subpart E of part 807 of this chapter subject to the limitations in § 862.9.