(70 days)
The DIA SCREEN® Reagent Strip for Urinalysis is a dip-and-read test strip for semiquantitative urinalysis. DIA SCREEN® Reagent Strips have been developed to allow health care professionals to test semiguantitatively for patient urine levels of specific gravity. ketone, glucose, protein, blood, nitrite, pH, ascorbic acid, billirubin, and urobilinogen by visual comparison with a color chart.
DIA SCREEN® Reagent Strips are plastic strips to which are affixed reagent areas. Several product configurations are included with this submission, but all configurations are limited to one, some or all of the following tests: specific gravity, ketone, glucose, protein, blood, nitrite, pH, ascorbic acid, bilirubin, and urobilinogen,
The reagent test areas on the DIA SCREEN® Reagent Strips are ready to use upon removal from the bottle and the entire reagent strip is disposable after use. The strips are to be read visually, requiring no additional laboratory equipment for testing.
Here's a breakdown of the acceptance criteria and the study that proves the device meets them, based on the provided text:
1. Table of Acceptance Criteria and Reported Device Performance
The device is considered substantially equivalent to existing marketed products, with the primary acceptance criterion being a high degree of correlation with these predicate devices and confirmatory tests. The general acceptance criterion for this device, which is a visual reagent test strip, is established through comparison to predicate devices, where "90% of all observations are within one color block."
| Analyte (Test) | Acceptance Criteria (Agreement within 1 Color Block with Predicate Devices or Confirmatory Test) | DIA SCREEN Lot 00226A Performance | DIA SCREEN Lot 00226B Performance |
|---|---|---|---|
| Specific Gravity | ≥ 90% | 96.5% | 96.5% |
| Ketone | ≥ 90% | 100% | 100% |
| Glucose | ≥ 90% | 100% | 100% |
| Protein | ≥ 90% | 100% | 100% |
| Blood | ≥ 90% | 98.3% | 98.3% |
| Nitrite | ≥ 90% | 100% | 100% |
| pH | ≥ 90% | 100% | 100% |
| Ascorbic Acid | ≥ 90% | 98.2% | 100% |
| Bilirubin | ≥ 90% | 100% | 100% |
| Urobilinogen | ≥ 90% | 100% | 100% |
All analytes meet or exceed the "90% of all observations are within one color block" criterion when adjusted for confirmatory test results.
2. Sample Size Used for the Test Set and Data Provenance
- Sample Size: The number of urine samples varied slightly by analyte, but generally the study used:
- 58 samples for Specific Gravity, Ketone, Glucose, Blood, and pH.
- 57 samples for Protein, Nitrite, and Ascorbic Acid.
- 48 samples for Bilirubin.
- 54 samples for Urobilinogen.
- Data Provenance: The study used fresh urine samples obtained at the medical facility (University of Minnesota Department of Medical Technology where the evaluation was conducted). This indicates prospective data collection from a clinical setting within the United States.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts
The document does not explicitly state the number of individuals who performed the visual readings or those who conducted the confirmatory tests as "experts" in the sense of specialized clinical diagnosticians establishing ground truth.
However, the study was conducted "under the direction of Nancy Brunzel, C.L.S., M.T., at the University of Minnesota Department of Medical Technology."
- Qualifications of Nancy Brunzel: C.L.S., M.T. (Certified Laboratory Scientist, Medical Technologist). These qualifications indicate expertise in clinical laboratory procedures and analysis.
- Implication for "Experts": While not explicitly stated how many readers were involved, it's reasonable to infer that the visual readings were performed by competent laboratory personnel, likely medical technologists or similar professionals, under Ms. Brunzel's supervision. The "ground truth" was established not solely by visual reading but significantly by confirmatory reference methods when discrepancies arose (see point 7).
4. Adjudication Method for the Test Set
The primary "adjudication" or reconciliation method was a confirmatory testing strategy.
- The study compared two lots of DIA SCREEN® strips against Ames Multistix 10 SG and Behring Rapignost strips.
- "When data between the two products did not agree within one color block, an alternate procedure (confirmation test)" was used.
- This implies a 2-way comparison (DIA SCREEN vs. Predicate) with a third, independent, and typically more accurate confirmatory method acting as the adjudicator for discrepancies.
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 done.
- This device is a visual dip-and-read non-AI based test strip. Therefore, the concept of "human readers improve with AI vs without AI assistance" is not applicable here. The study focuses on the performance of the DIA SCREEN® strips themselves against predicate devices and confirmatory tests, as read apparently by trained laboratory personnel.
6. If a Standalone (i.e. algorithm only without human-in-the loop performance) was Done
- No, a standalone (algorithm only) performance study was not done.
- This device relies on visual comparison with a color chart by a human reader. It is not an automated or AI-driven diagnostic system; it explicitly states "by visual comparison with a color chart" and "requiring no additional laboratory equipment for testing."
7. The Type of Ground Truth Used (expert consensus, pathology, outcomes data, etc.)
The ground truth for the test set was established using a combination of:
- Predicate device results: Initial comparison was made against Ames Multistix 10 SG and Behring Rapignost.
- Confirmatory (Reference) laboratory methods: For any discrepancies (results not within one color block) between the DIA SCREEN® strips and the predicate devices, a specific, established confirmatory test was employed. Examples include:
- Specific Gravity: Refractometer
- Ketone: Acetest
- Glucose: Chemstrip Reagent Strip (from Boehringer Mannheim)
- Protein: SSA (Sulfosalicylic Acid test)
- Blood: Microscopic Evaluation
- Nitrite: Microscopic Evaluation
- pH: pH Meter
- Ascorbic Acid: Urispec Reagent Strip (from Henry Schein)
- Bilirubin: Ictotest
- Urobilinogen: Chemstrip Reagent Strip (from Boehringer Mannheim)
This multi-faceted approach, heavily relying on established reference methods for discrepant results, serves as a strong form of ground truth.
8. The Sample Size for the Training Set
The document describes a clinical evaluation study (which serves as the "test set" in this context) but does not explicitly mention a separate "training set" for the DIA SCREEN® Reagent Strips. This is common for predicate-based 510(k) submissions, especially for visual assays. The implicit "training" for such devices often comes from the established clinical utility of the predicate devices and the internal development and quality control processes of the manufacturer to ensure the strips produce expected reactions.
9. How the Ground Truth for the Training Set Was Established
As no specific training set is mentioned in the provided text, the method for establishing its ground truth is also not described. The focus of this 510(k) submission is on demonstrating substantial equivalence through a direct comparison study (test set) against already established and approved predicate devices.
§ 862.1340 Urinary glucose (nonquantitative) test system.
(a)
Identification. A urinary glucose (nonquantitative) test system is a device intended to measure glucosuria (glucose in urine). Urinary glucose (nonquantitative) measurements are used in the diagnosis and treatment of carbohydrate metabolism disorders including diabetes mellitus, hypoglycemia, and hyperglycemia.(b)
Classification. Class II.