Fasting Isn't Required Before Lipid Levels Are Measured

In this evidence-based clinical review, the author identified three meta-analyses and five clinical practice guidelines that addressed whether fasting was required to measure lipid levels accurately and whether prediction of incident cardiovascular disease (CVD) events differed between fasting and nonfasting lipid levels.

The reviewer came to the following conclusions:

• Nonfasting testing results in clinically insignificant changes compared with fasting results in total, high-density, and low-density lipoprotein cholesterol levels and in only modest changes in triglyceride levels.

• Nonfasting and fasting lipid levels are at least equally predictive for adverse CVD events; nonfasting levels sometimes were more strongly predictive, presumably because nonfasting is the predominant metabolic condition for most people.

• Clinical practice guidelines have shifted during the past 5 years to endorse nonfasting testing in most routine circumstances.

• The recent European Atherosclerosis Society/European Federation for Laboratory Medicine guidelines recommend that, when triglyceride levels are >400 mg/dL with nonfasting testing, ordering a fasting test is appropriate (Eur Heart J 2016 Apr 26; [e-pub]).

• No studies directly compared the cost or convenience of nonfasting versus fasting testing, but a Danish study (where nonfasting testing has been the standard since 2009) showed that only 10% of patients who underwent nonfasting testing required repeat fasting testing.