November 12th, 2012
Nonfasting Lipid Testing Gains Growing Acceptance
Although fasting before a lipid test has long been recommended, a new study and accompanying commentaries make the case that nonfasting lipid levels are acceptable and may even be superior to fasting levels for the assessment of cardiovascular risk.
Investigators at the University of Calgary analyzed data from laboratory tests obtained from more than 200,000 people and found that fasting time caused little variation in total cholesterol and HDL cholesterol levels, although LDL levels and triglycerides varied by as much as 10% and 20%, respectively. The finding, the authors write in their paper in the Archives of Internal Medicine, “suggests that fasting for routine lipid level determinations is largely unnecessary,” although patients with triglyceride levels over 400 mg/dL may require a fasting lipid level or a direct measurement of LDL.
In an accompanying editorial, J. Michael Gaziano writes that “the incremental gain in information of a fasting profile is exceedingly small for total and HDL cholesterol values and likely does not offset the logistic impositions placed on our patients, the laboratories, and our ability to provide timely counseling to our patients. This, in my opinion, tips the balance toward relying on nonfasting lipid profiles as the preferred practice.”
In an invited commentary, Amit Khera and Samia Mora take note of some limitations of the study but conclude that “given the current lack of evidence for the superiority of fasting lipid testing, it is reasonable to consider nonfasting lipid testing in most individuals who present for a routine clinic visit.” Fasting levels may be indicated in people with high triglycerides and in high-risk patients such as diabetics.