Comparison of measured and calculated osmolality levels

Background Serum osmolality levels are measured to determine acid–base and electrolyte imbalance in serum. In cases where measurement is not possible, the serum osmolality value can be calculated by various calculation methods. In this study, we compared the Worthley osmolality calculation method which is used most frequently mentioned in literature and the measurements made with vapor pressure osmometer used in our laboratory. We compared whether there was a difference between the results obtained by measurement and calculation method in different age groups. Methods 221 serum samples of patients who were admitted to the Eskişehir Osmangazi University Hospital Biochemistry Laboratory between December 2016 and May 2018 were included in this study. Glucose, blood urea nitrogen and sodium values were recorded to determine the calculated osmolality values of the patients. Results There was a statistically significant difference between the measured osmolality values and the calculated osmolality values of the patients ( p