Evaluation of AUTION EYE AI-4510 flow cell morphology analyzer for counting particles in urine

We evaluated the performance of a novel flow cell morphology analyzer AUTION EYE AI-4510 for counting particles in urine.

Analytical performance was assessed according to the EFLM European Urinalysis Guideline 2023. Trueness was compared by analyzing 1.012 fresh urine samples with the AUTION EYE AI-4510 (ARKRAY, Inc., Kyoto, Japan) against phase-contrast visual microscopy. Poisson statistics were utilized in assessment of imprecision of particle counts both with quality control material and patient specimens.

Relative imprecision against theoretical Poisson imprecision, R(CV), was estimated to be 1.1 for red blood cells (RBC), 1.0 for white blood cells (WBC), 0.9 for squamous epithelial cells (SEC) and 1.1 for bacteria. The agreement with visual microscopy (Cohen's weighted kappa) was 0.93 for RBC, 0.95 for WBC, 0.90 for SEC, 0.79 for non-squamous epithelial cells (NSEC), 0.67 for combined casts, 0.90 for crystals and 0.88 for bacteria. No clinically significant bias was observed. Limits of quantitation at CV=30 % reached 4 × 10⁶/L for RBC and 5 × 10⁶/L for WBC. Differentiation of urinary crystals was improved as compared to previous data on digital cuvette imaging.

The ARKRAY AUTION EYE AI-4510 provided a desirable imprecision, met the criteria for linearity, LoQ and carry-over, and showed an optimum comparison to visual microscopy for RBC, WBC, SEC and crystals as defined in the EFLM European Urinalysis Guideline 2023. The identification of kidney damage is recommended to be improved by using user-defined review rules. Performance of bacteria counting needs to be confirmed against urine bacterial cultures.