Analytical performance evaluation of two automated urine chemistry analyzers using two levels of commercially available quality control material.
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OBJECTIVE: Evaluate two point-of-care urine chemistry analyzers, VetScan SA and VetLab UA using assayed, bilevel (two concentrations) urine quality control material to determine if performance is acceptable for semiquantitative clinical urine chemistry analysis. MATERIALS AND METHODS: Normal and abnormal urine quality control material sent to 23 veterinary practices was evaluated three times by each clinic on in-clinic automated urinalysis instruments. Accuracy, precision and clinical utility were evaluated. RESULTS: Normal urine quality control material: Results for blood, glucose, ketones and bilirubin were 100% accurate and precise for both analyzers, and pH values were accurately acidic to neutral. However, pH from VetScan SA had clinically significant negative bias. Abnormal urine quality control material: VetScan SA: blood, microalbumin and bilirubin were 100% accurate; glucose, ketones, and protein demonstrated 10% inaccuracy; pH demonstrated 34% inaccuracy. VetLab UA: blood, ketones and bilirubin were 100% accurate; glucose and protein demonstrated 10% inaccuracy; pH was 100% accurately neutral to alkaline. CLINICAL SIGNIFICANCE: VetScan SA had marked negative pH bias versus VetLab UA resulting in clinically significant, overly acidic results. Specific gravity, nitrite, and leukocyte test pads should not be used. Both instruments had excellent performance in normal quality control material. While blood, glucose, protein and bilirubin are correctly identified as present in abnormal quality control material, exact concentrations cannot be interpreted due to imprecision. Only semiquantitative results, not numerical values implying quantification, should be reported from urine test strips.
author list (cited authors)
Hokamp, J. A., Freeman, K., & Harr, K. E.
complete list of authors
Hokamp, JA||Freeman, K||Harr, KE