Comparison plasma osmolality between freezing point depression method and different calculation formulas / 国际检验医学杂志

ABSTRACT

Objective Sixteen common blood osmotic pressure calculation formulas were investigated to evaluate the calculation formula of the plasma osmotic pressure formula and the freezing point depression method.The collected data were used to simulate a formula that was consistent with the patient′s plasma osmotic pressure.Methods The osmotic pressure of plasma was measured by the freezing point descent method.Plasma sodium (Na), potassium (K), chloride (Cl), glucose (Glu), and urea (Urea) concentrations were measured by using a Vitros 5.1dry chemistry analyzer.Sixteen formulas were used to calculate the corresponding plasma osmotic pressure.The Passing-Bablok regression was used to determine the goodness of fit and paired t test was performed with the measured values.A multiple linear regression and paired t test method was used to fit a formula that most closely matched the measured values.Results The formula of plasma osmotic pressure and the measured value was the most consistent with the formula 1.86 (CNa+CK) +CGlu+CUrea+10;the regression formula using multiple linear regression was 1.86CNa+2.75CK+1.16CGlu+0.92CUrea+5.77.Conclusion It is tentatively concluded that the formula 1.86CNa+2.75CK+1.16CGlu+0.92CUrea+5.77can be used as the formula for calculating plasma osmolality.