Aim: Measurement uncertainty provides information about the limits at which the measured value may vary as a result of random effects in a biochemical measurement. It is a quantitative indicator of the quality of the result obtained and allows us to estimate the extent to which this result represents the actual value. The aim of our study; was to investigate the effect of the ethanol test on the test results by calculating the measurement uncertainty.

Materials and Methods: 730 low-level and 730 high-level internal quality control data and external quality control data were used in our laboratory for our study. The measurement uncertainty value of the ethanol analysis was calculated according to the Eurachem/CITAC Guide CG 4.

Results: The in-laboratory reproducibility (uRW) value was calculated as 1.31%, the external quality control uncertainty component (u(bias)) value as 2.64%, and the measurement uncertainty value of ethanol as ±5.8% at a 95% confidence interval. According to this result, 7 (0.32%) ethanol results were close to the threshold value. According to the obtained ethanol measurement uncertainty value, it can be considered that 5 (0.23%) results are low and 2 (0.09%) results are high.

Conclusion: It was determined that 99.4% of the total 2151 ethanol results were not affected by measurement uncertainty. For ethanol testing in our laboratory, although there is a low measurement uncertainty unlike most studies, it is aimed to further reduce the measurement uncertainty with stricter analytical performance conditions so that values close to legal limits are not affected.