The use of the non-fasted triglycerides in assessing cardiovascular risk
Ryan and colleagues (24th March 2018) should be congratulated on the clarity of their article on Dyslipidaemia and cardiovascular disease (Ryan A, Heath S, Cook P (2018) BMJ 2018; 360; k835). Whilst they are correct in saying that there is now less emphasis on the use of fasted lipid profiles, it is worth noting that the original Friedewald equation (Friedewald WT, Levy RI, Fredrickson DS (1972) 18; 6; 499-502) was predicated on the use of a fasted lipid profile, and makes the assumption that very low density lipoprotein (VLDL) is the only triglyceride-rich lipoprotein present. The accuracy of the LDL-cholesterol estimate is therefore likely to be affected by using a non-fasted sample, and this would be particularly important near the LDL>4.9 mmol/L decision cut-off. It is also worth noting that many clinical laboratories would not routinely measure triglycerides in a non-fasted sample. Obviously this can be resolved by obtaining a fasted lipid profile for patients in whom the non-fasted, calculated LDL-cholesterol is borderline, or by using a direct assay for LDL-cholesterol.
Competing interests: No competing interests