Objective: The measurement of serum alcohol level is one of the most common tests in forensic and toxicologic laboratories. Measurement uncertainty is an analytical data which evaluate the reliability of a test. This study aims to evaluate the measurement uncertainty of the ethyl alcohol test using the internal and external quality control results of Elazig Mental Health Hospital Centeral Clinical Laboratory and to retrospectively examine serum ethanol analysis results analyzed in our laboratory in 2016.

Material and Methods: Standard, combined and expanded uncertainty values of serum ethyl alcohol analysis were calculated at six steps based on Nordest guide. A total of 566 serum ethanol test results analyzed in our laboratory in 2016 were retrospectively examined.

Results: As a result of the analyses made by using datas of our laboratory, uncertainty value of ethanol test was calculated as %14.2. The test results of 10 patients(1.76%) were near to cut-off (between 42.9- 57.1 mg/dl). It was observed that all of remaining patients (98.24%) were not affected by measurement uncertainty.

Conclusion: Uncertainty in measurement is a parameter that indicates the distribution of the probabilities attributed to the result of measurement and reported with result of measurement. The uncertainty value of ethyl alcohol test was determined as ±%14.2 in the %95 confident interval at our laboratory. It was observed that 1.76% of all patients were affected by uncertainty values.