(149 days)
The GSP Neonatal GALT kit is intended for the quantitative determination of r ne Sose - 1-phosphate uridyl transferase (GALT) activity in blood specimens dried on filter paper as an aid in screening newborns for classical galactosemia caused by GALT deficiency using the GSP™ instrument.
The GSPTM Neonatal GALT assay is an adaptation of the quantitative enzymatic assay of Beutler and Baluda. The fluorescence is measured with the GSP Instrument using an excitation wavelength of 355 nm and an emission wavelength of 460 nm. The GSP Neonatal GALT assay uses prompt fluorescence technology.
Here's a breakdown of the acceptance criteria and study information for the GSP Neonatal GALT kit, based on the provided 510(k) summary:
Acceptance Criteria and Device Performance
The provided document does not explicitly state pre-defined acceptance criteria in terms of specific thresholds for precision, linearity, detection limits, or agreement with the predicate device. Instead, it presents the results of these performance characteristics studies and a comparison with the predicate device.
However, based on the intent of the comparison study with the predicate device, we can infer some implicit acceptance goals relating to agreement with the established method. The screening performance tables directly compare the classification of samples between the new device and the predicate.
Inferred Acceptance Criteria & Reported Device Performance:
| Performance Metric | Inferred Acceptance Criteria (Implicit) | Reported Device Performance |
|---|---|---|
| Precision (CV%) | Values within acceptable clinical laboratory ranges for quantitative assays, typically demonstrating good reproducibility. (Specific quantitative targets for CV% are not stated, but results are presented to demonstrate low variability across multiple conditions.) | Within-Run Variation: CV% range from 3.0% to 12.8% |
| Within-Lot Variation: CV% range from 4.9% to 14.3% | ||
| Total Variation: CV% range from 5.2% to 15.9% | ||
| Linearity | Demonstrated linearity across the expected measuring range for clinical utility. | Linear throughout the measuring range of 2.5 U/dL to 25 U/dL. Maximum observed difference between linear and 3rd order regression models is -2.6% for GALT activities >4 U/dL, and max absolute difference of 0.07 U/dL for GALT activities ≤ 4 U/dL. |
| Detection Limit (LoQ) | Ability to accurately quantify GALT activity at low concentrations relevant for screening GALT deficiency. | LoB: 1.6 U/dL |
| LoD: 2.5 U/dL | ||
| LoQ: 2.5 U/dL (with total CV ≤ 20%) | ||
| Analytical Specificity | No significant interference from common endogenous substances or therapeutic compounds (e.g., icteric, lipemic samples, ascorbic acid, galactose). Minimal or explainable interference from other relevant substances (e.g., glutathione, GAL-1-P) at clinically relevant concentrations. | No interference from icteric (bilirubin ≤ 40 mg/dL), lipemic (Intralipid ≤ 1000 mg/dL), ascorbic acid (≤ 3 mg/dL), or galactose (≤ 50 mg/dL). |
| Glutathione: Interference (decrease up to 63%) above 18.8, 37.5, 56.3 mg/dL at 3, 6, 12 U/dL GALT activity respectively. | ||
| GAL-1-P: No effect on 3 U/dL samples; interference (decrease up to 37%) on 6 and 12 U/dL samples at 12.5 mg/dL. | ||
| Total protein (HSA): No effect on 12 U/dL samples; interference (increase up to 30%) on 3 and 6 U/dL samples above 3000 mg/dL. | ||
| Comparison with Predicate - Screening Performance (using 0.5th percentile cut-off) | High overall agreement, positive percent agreement, and negative percent agreement with the predicate device (NG-1100/4100), demonstrating comparable screening classification. | Overall percent agreement: 99.6% (CI 99.3%-99.9%) |
| Positive percent agreement: 92.9% (CI 83.9%-100%) | ||
| Negative percent agreement: 99.8% (CI 99.5%-100%) | ||
| Comparison with Predicate - Screening Performance (using 1.0st percentile cut-off) | Similarly high agreement metrics at a different cut-off. | Overall percent agreement: 99.3% (CI 98.9%-99.7%) |
| Positive percent agreement: 84.9% (CI 74.3%-95.5%) | ||
| Negative percent agreement: 99.6% (CI 99.3%-99.9%) | ||
| Comparison with Predicate - Screening Performance (using 1.5th percentile cut-off) | Similarly high agreement metrics at a different cut-off. | Overall percent agreement: 98.9% (CI 98.4%-99.4%) |
| Positive percent agreement: 83.6% (CI 73.5%-93.7%) | ||
| Negative percent agreement: 99.3% (CI 99.0%-99.7%) |
Study Information
- Sample size used for the test set and the data provenance:
- Precision Study: 8 samples (S1-S8), each tested with 206-216 replicates (n values).
- Detection Limit Study:
- LoB: 83 GALT deficient samples
- LoD: 351 determinations of five low-level samples
- LoQ: 209 replicates
- Analytical Specificity Study: Whole blood samples with three different GALT activities (approx. 3, 6, and 12 U/dL) were tested. Hematocrit effect was tested on three whole blood samples (approx.
§ 862.1315 Galactose-1-phosphate uridyl transferase test system.
(a)
Identification. A galactose-1-phosphate uridyl transferase test system is a device intended to measure the activity of the enzyme galactose-1-phosphate uridyl transferase in erythrocytes (red blood cells). Measurements of galactose-1-phosphate uridyl transferase are used in the diagnosis and treatment of the hereditary disease galactosemia (disorder of galactose metabolism) in infants.(b)
Classification. Class II.