From the Guidelines
A lipid profile for a healthy 34-year-old undergoing baseline bloodwork does not necessarily need to be done in a fasting state. Non-fasting lipid testing is now considered acceptable for routine screening in most healthy adults, as the difference between fasting and non-fasting total cholesterol and HDL cholesterol values is clinically insignificant 1. While triglycerides may be slightly elevated after eating, this actually represents the body's normal metabolic state and can still provide valuable information. LDL cholesterol calculated from non-fasting samples remains adequate for risk assessment in most cases. Non-fasting testing improves patient compliance, reduces laboratory burden, and eliminates the risk of hypoglycemia in vulnerable patients. Some key points to consider include:
- The 2019 American College of Cardiology/American Heart Association guideline supports the use of non-fasting lipid profiles for risk assessment in primary prevention and for assessment of baseline LDL-C levels before the initiation of a statin in primary and secondary prevention 1.
- Non-fasting samples can be used for risk assessment, and if more precision is necessary, fasting lipids can be measured, but a non-fasting sample is reasonable for most situations 1.
- However, if the initial non-fasting results show significantly elevated triglycerides (>400 mg/dL) or if the patient has a known disorder of lipid metabolism, a follow-up fasting test may be warranted. For most healthy 34-year-olds, the convenience of non-fasting testing outweighs any minor variations in results compared to fasting samples.
From the Research
Lipid Profile Testing for a Healthy 34-Year-Old
Fasting Requirements
- The requirement for fasting before a lipid profile test for a healthy 34-year-old undergoing baseline bloodwork can be assessed based on several studies 2, 3, 4, 5, 6.
- A study published in 2016 found that fasting for only 8 hours before measurement of serum triglyceride may be sufficient, as there was no significant difference in triglyceride levels between those who fasted for 8 hours and those who fasted for 12 hours 2.
- Another study from 1992 investigated postprandial changes of triglycerides in healthy males and found that total triglycerides increased significantly after a standardized lipid load, but this does not directly address the fasting requirement for baseline bloodwork 3.
- A joint consensus statement from the European Atherosclerosis Society and European Federation of Clinical Chemistry and Laboratory Medicine in 2016 recommended that non-fasting lipid profiles be used routinely, as the maximal mean changes after habitual meals are not clinically significant 4.
- Additional studies support the use of non-fasting lipid profiles for improving patient compliance and safety, especially for routine screening 5, 6.
Clinical Implications
- The use of non-fasting lipid profiles has been shown to have minimal impact on the clinical implications of lipid testing, including the prediction of cardiovascular disease 4.
- Laboratory reports should flag abnormal concentrations based on desirable concentration cut-points, regardless of fasting status 4.
- Fasting may still be considered in certain situations, such as when non-fasting triglycerides are >5 mmol/L (440 mg/dL) or for monitoring triglyceride and low-density lipoprotein cholesterol levels in patients taking lipid-lowering medications 4, 6.