The standardization of urine particle counting in medical laboratories--a Polish experience with the EQA programme

Given the common problems with the standardization of urine particle counting methods and the great variability in the results obtained by Polish laboratories under international Labquality External Quality Assessment (EQA), we initiated educational recovery activities.

Detailed instructions on how to perform the standardized examination were sent to EQA participants, as was a questionnaire forms which enabled information to be gathered in respect to the procedures being applied. Laboratory results were grouped according to the method declared on the EQA 'Result' form or according to a manual examination procedure established on the basis of the questionnaire. The between-laboratory CVs for leukocyte and erythrocyte counts were calculated for each group and compared using the Mann-Whitney test.

Significantly lower between-laboratory CVs (p = 0.03) were achieved for leukocyte counting among the laboratories that analysed control specimens in accordance with standardized procedures as compared with those which used non-standardized procedures. We also observed a visible lower variability for erythrocyte counting. Unfortunately despite our activities, only a few of the Polish laboratories applied the standardized examination procedures, and only 29% of the results could have been considered to be standardized (16% - manual methods, 13% - automated systems).

The standardization of urine particle counting methods continues to be a significant problem in medical laboratories and requires further recovery activities which can be conducted using the EQA scheme.