Results obtained in 6 surveys (12 samples) of external quality programme performed in years 2000–2002 were used for calculation of uncertainty in qualitative measurement of routine urine analytes using the dipstick method. Uncertainties were evaluated according to the new approach proposed by EURACHEM-CITAC 2002 as false positive (FPR) or false negative (FNR) rates.ValuesFNR calculated for positive samples reached for glucose 5%, and even more than 10% for leukocytes, bilirubin and nitrite. In detection of positive values we ascertained better situation – no FPR value was over 10% and only for leukocytes and erythrocytes exceeded 5%. Using the reflectometers for detection instead of visual approach is more effective for uncertainty decrease in negative samples than in positive ones. Very strong dependency on the type of analytical systems was observed. Uncertainties obtained by use of different dipsticks and equipment were often differed. For example uncertainty of leukocytes and erythrocytes detection in negative samples is 5–10 times lower for certain reflectometric systems than for other reflectometric systems. On other hand more than 90% of false negative nitrite detection results were obtained by visual detection used dipsticks Lachema, and more than 60% false negative reflectance detection of bilirubin were obtained by use of Bayer and DOT measurement systems.

        Key words: qualitative detection, uncertainty, false negative ratio, false positive ratio, urine dipsticks, diagnostic strips.