Correlations between Direct and Calculated Low‐Density Lipoprotein Cholesterol Measurements in Children and Adolescents

Background Low‐density lipoprotein cholesterol (LDL‐C), as a modifiable risk factor for atherosclerotic cardiovascular disease, should be assessed and monitored. This study compared directly measured and Friedewald‐estimated LDL‐C values in children and adolescents. Methods Blood samples were collected from 464 children and adolescents. Calculated LDL‐C (CLDL‐C) levels were estimated using the Friedewald formula for any triglyceride value below 4.6 mmol/L. Direct LDL‐C (DLDL‐C) levels were measured on an ARCHITECT c8000 Abbott Clinical Chemistry Analyzer. The differences in LDL‐C were then calculated. Results The correlation coefficients (R) between DLDL‐C and CLDL‐C were 0.978 (P = .148) and R = 0.970 (P = .052) for children and adolescents, respectively. Children with LDL‐C values above 4.92 mmol/L had a correlation value of 0.971 (P = .419). The correlation and agreement between DLDL‐C and CLDL‐C in adolescents were moderate for LDL‐C below 2.85 mmol/L (R = 0.806; 84.1%) and improved above 2.85 mmol/L (R = 0.978; 91.5%). In children, good correlations between DLDL‐C and CLDL‐C were observed for normal (