(78 days)
HiChem BUN/Urea Reagent (product no. 70006) is for the quantitative determination of urea nitrogen in serum. plasma and urine. Plasma urea levels are affected by a wide variety of factors including diet, increased protein catabolism and mild dehydration as well as many renal diseases. The major value of plasma urea measurement is in distinguishing between renal and non-renal related causes.
The HiChem BUN/Urea Reagent determines urea nitrogen through enzymatic hydrolysis by urease. The rate of this reaction, and the quantity of urea nitrogen in the specimen is monitored through the measurement of the resulting ammonia which oxidizes NADH to NAD in the presence of ox-keto-glutarate and glutamate dehydrogenase. The reagent is supplied as two liquid-stable reagent components which are intended to be combined, either before or during use, in the approximate ratio of 1 part BUN/Urea Enzyme Reagent and 5 parts BUN/Urea Buffer. The BUN/Urea Enzyme Reagent can also be used as a start reagent and combined with the reagent buffer after sample addition.
This document describes the performance of the HiChem BUN/Urea Reagent and compares it to existing reagents, rather than an AI-powered device. Therefore, many of the requested elements for an AI device study (e.g., sample size for AI test set, number of experts for ground truth, adjudication method, MRMC study, standalone performance, training set details) are not applicable.
However, I can extract the acceptance criteria and reported performance based on the provided text for the HiChem BUN/Urea Reagent.
1. Table of Acceptance Criteria and Reported Device Performance
The document doesn't explicitly state "acceptance criteria" with numerical thresholds for all evaluated aspects. Instead, it presents performance metrics and makes claims about substantial equivalence to predicate devices, linearity, and stability. I will infer acceptance criteria where possible from the claims made (e.g., linearity to at least 150 mgN/dL, shifts less than specified values for stability). For comparative studies, the acceptance is implied if the regression statistics (r², Sy.x) demonstrate strong agreement with the predicate device.
Manual Procedure:
| Performance Characteristic | Acceptance Criteria (Inferred) | Reported Device Performance (HiChem BUN/Urea Reagent) |
|---|---|---|
| Precision | Demonstrated by replicate assay | Low serum control (n=30): Mean 8.7 mgN/dL, within run SD 0.48 mgN/dL, total SD 0.58 mgN/dL |
| Mid. serum control (n=30): Mean 25.7 mgN/dL, within run SD 0.73 mgN/dL, total SD 0.70 mgN/dL | ||
| High serum control (n=30): Mean 52.1 mgN/dL, within run SD 0.93 mgN/dL, total SD 1.02 mgN/dL | ||
| Low urine pool (n=30): Mean 15.4 mgN/dL, within run SD 0.71 mgN/dL, total SD 0.90 mgN/dL | ||
| High urine pool (n=30): Mean 53.3 mgN/dL, within run SD 1.20 mgN/dL, total SD 1.54 mgN/dL | ||
| Linearity | Linear to at least 150 mgN/dL | Regression: (HiChem Results) = 0.1 mgN/dL + 0.986 × (Standard Value), r² = 1.000, Sy.x = 0.5 mgN/dL. (Spans claimed linear range) |
| Method Comparison (Serum/Plasma vs. Sigma) | Demonstrates substantial equivalence and produces equivalent results with clinical purpose. Implied strong correlation (high r²) and low bias (Sy.x). | 80 mixed serum and plasma specimens: |
| (HiChem Results) = 0.7 mgN/dL + 0.977 × (Sigma Results) | ||
| r² = 0.996, Sy.x = 1.00 mgN/dL | ||
| Method Comparison (Urine vs. BMD) | Demonstrates substantial equivalence and produces equivalent results with clinical purpose. Implied strong correlation (high r²) and low bias (Sy.x). | 39 urine specimens: |
| (HiChem Results) = 1.9 mgN/dL + 0.966 × (BMD Results) | ||
| r² = 0.990, Sy.x = 1.82 mgN/dL | ||
| Interfering Substances (Additives) | Observed differences less than 1% and statistically insignificant | Use of sodium and lithium heparin, EDTA, citrate, and iodoacetate are acceptable. Observed differences |
§ 862.1770 Urea nitrogen test system.
(a)
Identification. A urea nitrogen test system is a device intended to measure urea nitrogen (an end-product of nitrogen metabolism) in whole blood, serum, plasma, and urine. Measurements obtained by this device are used in the diagnosis and treatment of certain renal and metabolic diseases.(b)
Classification. Class II.