Abstract Objectives Automated urine particle analyzers are increasingly employed in clinical laboratories to standardize urinalysis. These systems can reduce workload, turnaround time and the inter-observer variation. This study aimed to assess the performance of five automated urine particle analyzers in detecting and categorizing dysmorphic erythrocytes (isomorphic-, dysmorphic erythrocytes, acanthocytes) and pathological casts, in particular erythrocyte casts, for screening of glomerular vs. non-glomerular hematuria, compared to manual phase-contrast microscopy, as the reference method. Methods The analytical performance of five automated urine particle analyzers, Atellica UAS 800, FUS-3000Plus, iQ200, SediMAX conTRUST Pro, and UF-4000, for measuring and categorizing erythrocytes and pathological casts was evaluated. Urine samples spiked with erythrocytes were used to assess precision and performance characteristics, while 68 urine samples from patients with glomerular hematuria were analyzed for concordance. Results Automated analyzers demonstrated acceptable precision at middle and high erythrocyte concentrations. At low levels, the iQ200 performed relatively well and the SediMAX met the manufacturer’s precision criteria. Manual on-screen review was required for 90 % of samples analyzed to achieve acceptable results for dysmorphic erythrocytes and cast detection. None of the analyzers exhibited strong agreement with manual microscopy for identifying isomorphic-, dysmorphic erythrocytes or acanthocytes (concordance <0.80), whereas the FUS-3000 and UF-4000 had relatively higher sensitivities for pathological cast detection (58.6 and 69.6 %, respectively). Conclusions Current automated urine particle analyzers are limited in accurately identifying dysmorphic erythrocytes and pathological casts, necessitating manual microscopy for reliable assessment. While automation offers potential for standardization and efficiency, significant technological advancements are required to improve diagnostic accuracy, reliability, and clinical applicability.
Luimstra et al. (Fri,) studied this question.