title: LDL-cholesterol: Friedewald calculated versus direct measurement-study from a large Indian laboratory database.
abstract: BACKGROUND
  Validity of Friedewald formula (FF) in patients with serum triglycerides (TGs) <400 mg/dl is unclear.
  
  
  METHODS
  We compared low-density lipoprotein (LDL)-cholesterol calculated by FF to directly measured LDL in a laboratory database of 14,620 lipid profile samples from south India.
  
  
  RESULTS
  LDL by FF correlated with directly measured LDL with correlation coefficient of 0.89 with the best correlation seen in TG levels 100-150. Higher level of TG (>200) underestimates the LDL calculated by FF particularly at LDL values <70 mg/dl. On the other hand, LDL is overestimated by FF in more than 70% of cases at LDL levels >130 mg/dl.
  
  
  CONCLUSIONS
  We suggest repeating the LDL by direct assay techniques particularly in patients with TG >200 and when LDL <70 or >130. This helps in correctly stratifying the coronary artery diseases' (CADs') risk and goals of treatment.
authors.affiliation: Consultant, Endocrinology Diabetes and Bariatric Medicine, Narayana Health City, Bangalore, Karnataka, India.
authors.forename: Subramanian
authors.initials: S
authors.lastname: Kannan
authors.affiliation: Endocrine and Speciality Clinic, Chennai, India.
authors.forename: Shriraam
authors.initials: S
authors.lastname: Mahadevan
authors.affiliation: Assistant Professor Endocrinology, Chettinad Medical College, Chennai, India.
authors.forename: Bharath
authors.initials: B
authors.lastname: Ramji
authors.affiliation: Consultant Endocrinologist, Arka Center for Hormonal Health, Chennai, India.
authors.forename: Muthukumaran
authors.initials: M
authors.lastname: Jayapaul
authors.affiliation: Department of Clinical Endocrinology, Alpha Hospital and Research Centre, Anuppanady, Madurai, Tamil Nadu, India.
authors.forename: V
authors.initials: V
authors.lastname: Kumaravel
keywords: Friedewald formula; LDL cholesterol; triglyceride