266 I. Ryden et al. Table I. Total analytical imprecision at two levels for the Vitros methods used to calculate the reference intervals. Table I. (Continued). Concentration (two levels) Coefﬁcient of variation (CV) Analyte Alanine aminotransferase (ALT) Albumin Alkaline phosphatase Apolipoprotein A1 Apolipoprotein B Bilirubin Calcium Chloride Cholesterol HDL-cholesterol Creatinine Creatine kinase C-reactive protein (CRP) g-Glutamyltransferase (GGT) Glucose Iron Lipase Magnesium Phosphate Potassium Lactate dehydrogenase (LDH) 0.66 mkat/L 3.15 mkat/L 23 g/L 47 g/L 1.6 mkat/L 8.5 mkat/L 1.08 g/L 1.91 g/L 0.89 g/L 1.84 g/L 26 mmol/L 256 mmol/L 2.1 mmol/L 3.0 mmol/L 81 mmol/L 105 mmol/L 3.8 mmol/L 6.3 mmol/L 1.0 mmol/L 1.6 mmol/L 76 mmol/L 504 mmol/L 2.7 mkat/L 15.2 mkat/L 5.5 mg/L 84 mg/L 1.2 mkat/L 7.4 mkat/L 4.2 mmol/L 6.5 mmol/L 19 mmol/L 45 mmol/L 2.7 mkat/L 9.2 mkat/L 2.7 mkat/L 10.0 mkat/L 0.9 mmol/L 1.8 mmol/L 1.1 mmol/L 2.3 mmol/L 3.1 mmol/L 5.4 mmol/L 4.9% 1.3% 2.4% 1.8% 2.8% 3.1% 2.1% 3.7% 2.1% 1.7% 2.9% 1.1% 1.7% 1.5% 0.9% 0.8% 1.0% 1.0% 2.5% 2.2% 1.3% 1.2% 3.3% 4.1% 5.0% 5.9% 2.6% 1.8% 2.5% 2.4% 2.2% 1.5% 2.5% 1.5% 2.6% 1.0% 1.7% 1.2% 1.4% 0.7% 0.9% 0.7% Concentration (two levels) Coefﬁcient of variation (CV) 117 mmol/L 143 mmol/L 1.3 g/L 6.0 g/L 1.3 mmol/L 2.7 mmol/L 250 mmol/L 630 mmol/L 5.6 mmol/L 20.3 mmol/L 1.5% 1.7% 2.0% 3.7% 0.7% 1.1% 1.2% 1.4% 2.5% 2.2% Analyte Sodium Transferrin Triglycerides Urate Urea following variables were also calculated: ApoB/ ApoA1 ratio, LDL-cholesterol (LDL-cholesterol = cholesterol – (HDL-cholesterol + Triglycerides/ 2.2)), LDL/HDL ratio, total iron binding capacity (TIBC) (TIBC (mmol/L) = 25 transferrin (g/L)), and transferrin saturation (iron saturation (%) = 100 iron/TIBC). Blood glucose was analyzed in whole blood on a HemoCue instrument (HemoCue , Ängelholm, Sweden) with reagents from the manufacturer. Statistical calculations Calculations of reference values were performed by bootstrap estimation utilizing RefVal 4.0 (Department of Clinical Chemistry, Rikshospitalet, N-0027 Oslo, Norway). RefVal fulﬁlls the recommendations of the International Federation of Clinical Chemistry on the statistical treatment of reference values (10,11). Com- parisons between groups were performed with Mann– Whitney U test (Statistica, StatSoft, Tulsa, OK, USA). Results Description of the study population Basic characteristics of the total samples are presented in Table III. After the exclusion of individuals with diabetes the study population consisted of 373 females (338 without CVD) and 354 males (274 without CVD). Reference values The 2.5 and 97.5 percentiles for males and females with and without CVD are presented in Table IV. The corresponding values obtained in the Nordic Reference Interval Project (NORIP) are presented