For many years it has been standard to test bloodlipid levels in the fasting state. However, since 2009 starting in Denmark the utility of nonfasting testing became the test of choice. It is good to realize that except for a few hours in the morning, most of the people spend the majority of their lives in the nonfasting state. Moreover, it is much more convenient for patients not to have to come back for fasting testing, healthcare delivery is more streamlined and evoked hypoglycemia in patients with diabetes is avoided.
Several studies of fasting vs nonfasting lipid testing have shown that the differences between fasting and nonfasting lipidlevels are limited and that most of them do not change substantially after eating. It is good to realize that non-HDL cholesterol is now considered to be a better predictor of cardiovascular disease risk than LDL chlesterol.
Even more important is that a large evidence-based review of published literature from over 300,000 individuals found equal lipid relationship for predicting incident CVD events using nonfasting lipids. Another trial reported high concordance of fasting and nonfasting lipid levels for classifying participants into appropiate ASCVD (atherosclerotic cardiovascular disease) risk categories (94.8 %). According to the authors, these results suggest that routine measurement of nonfasting lipid levels may help facilitate ASCVD risk screening and treatment, including consideration of when to initiate statin therapy.
There are still circumstances where fasting testing should be used, such as in patients with genetic dyslipidemia, if patients have severe hypertriglyceremia (> 4.5 mmol/l ) and in patients with pancreatitis. Triglycerides values fluctuate the most between the fasting and nonfasting state and this could impact triglyceride disorder management and the accuracy of LDL cholesterol estimation through the Friedewald formula (in which LDL cholesterol = total cholesterol – HDL cholesterol – 0.45 x triglcerides).
In conclusion: nonfasting lipid testing has advantages vs fasting testing, both with respect to patient comfort as the streamline of healthcare delivery. Moreover, as far as CVD risk management is concerned fasting lipid testing has no advantages vs nonfasting testing apart from a few rather rare circumstances.
