Analytical performance evaluation of two automated urine sediment analysers using two levels of commercially available quality control material.

Abstract

Evaluate the in-clinic performance of point-of-care sediment analysers, Analyzer V (Vetscan SA, Abaxis) and Analyzer S (SediVue DX, IDEXX), using assayed, bilevel (2 concentrations) urine quality control material to determine if instrument specifications are acceptable for semi-quantitative clinical urine sediment analysis. Accuracy, precision and clinical utility of Analyzer V and Analyzer S measurements were evaluated using a bilevel, assayed quality control material in 23 veterinary practices. Photomicrographs taken by the instruments facilitated manual review and quality assessment. Analyzer V and Analyzer S under-identified the presence of cystine crystals with 83 and 13% inaccuracy in the positive quality control material, respectively. Analyzer V and Analyzer S over-reported bacteria in the sterile quality control material with 82 and 94% specificity, respectively. Analyzer V and Analyzer S reported RBCs and WBCs within manufacturer specifications with excellent sensitivity (93 to 100%) and specificity (100%). Additional improvement is needed to better classify crystal types and reduce false positives for bacteria before clinical use. While normal samples can generally be trusted, a manual review of abnormal samples is required to ensure that clinically important urine components are correctly evaluated. Future studies should evaluate the performance of these instruments with species-specific urine sediment.