Evaluation of the performances of the iQ(®)200 ELITE automated urine microscopy analyser and comparison with manual microscopy method

• Published in: Pathologie biologie (Paris) Vol. 59; no. 5; pp. 264 - 268
• Main Authors: Dewulf, G, Harrois, D, Mazars, E, Cattoen, C, Canis, F
• Format: Journal Article
• Language: French
• Published: France 01-10-2011
• Subjects: Autoanalysis; Crystallization; Erythrocytes - cytology; Humans; Leukocytes - cytology; Microscopy - instrumentation; Microscopy - methods; Reproducibility of Results; Sensitivity and Specificity; Urinalysis - instrumentation; Urinalysis - methods; Urinalysis - standards; Yeasts - cytology
• ISSN: 1768-3114
• DOI: 10.1016/j.patbio.2009.10.006

Microscopy urinalysis is one of the last manual analyses in laboratories and it is difficult to control. The automation of this analysis permits our laboratory to standardise this test. We performed an evaluation of the iQ(®)200 ELITE's performances and compare the data to the manual microscopy method which is considered as "the gold standard". The repeatability achieved at different levels of leukocytes and erythrocytes showed CVs below 10% for pathological values. Inter-run repeatability is 5,57% and carry-over is negligible if we take into consideration the linearity of the formed particles. Compared to the manual method, sensitivity (Se) of the analyser for leukocytes and erythrocytes are respectively 94.85 and 100%, the negative predictive value (NPV) are 92.91 and 100%, respectively. The weaknesses of the specificity (Sp) and positive predictive value (PPV) of erythrocytes (24.22 and 41.92%) are due to the lack of sensibility of the manual method. Also, the weak PPV of yeasts, casts and crystals are due to the better detection of those particles with the iQ(®)200's image recognition system than with manual method. NPV for all the urine formed particles are excellent, they are between 98 and 100%. The iQ(®)200 ELITE permits us to standardise and control this test for a future accreditation of the laboratory. We also significantly increase the turn around time.