Break the fast? Update on patient preparation for cholesterol testing

To provide an update on the clinical usefulness of nonfasting versus fasting lipid testing to improve patient compliance, patient safety, and clinical assessment in cholesterol testing.

Recommendations are identified as supported by good, fair, and poor (conflicting or insufficient) evidence, according to the classifications adopted by the Canadian Task Force on Preventive Health Care.

Screening for dyslipidemia as a risk factor for coronary artery disease and management of lipid-lowering medications are key parts of primary care. Recent evidence has questioned the fasting requirement for lipid testing. In population-based studies, total cholesterol, high-density lipoprotein cholesterol, and non-low-density lipoprotein cholesterol all varied by an average of 2% with fasting status. For routine screening, nonfasting cholesterol measurement is now a reasonable alternative to a fasting cholesterol measurement. For patients with diabetes, the fasting requirement might be an important safety issue because of problems with hypoglycemia. For the monitoring of triglyceride and low-density lipoprotein cholesterol levels in patients taking lipid-lowering medications, fasting becomes more important.

Fasting for routine lipid level determinations is largely unnecessary and unlikely to affect patient clinical risk stratification, while nonfasting measurement might improve patient compliance and safety.