From the Guidelines
A lipid profile in a fasted state is not necessary for most patients, as a nonfasting lipid profile provides acceptably accurate measures for risk calculation 1.
Key Points
- Nonfasting lipid profiles are generally adequate to document baseline lipid levels prior to initiation of statin therapy, with modest differences in LDL-C levels between fasting and non-fasting samples 1.
- Fasting lipid measures are only indicated if the purpose is to measure or monitor triglyceride levels, or if triglyceride levels are greater than 400 mg/dL 1.
- Triglyceride measurement has the advantage of being a direct, precise, and accurate measurement of all triglycerides in plasma, but high triglycerides should be viewed as a marker of high levels of cholesterol in triglyceride-rich lipoproteins 1.
- Remnant cholesterol, which can be estimated as total cholesterol minus LDL cholesterol minus HDL cholesterol, is a better predictor of ASCVD risk than triglycerides alone 1.
Clinical Implications
- Nonfasting lipid profiles can be used to estimate ASCVD risk and document baseline LDL-C levels in most patients, reducing the burden on patients and laboratories 1.
- Fasting lipid profiles should be reserved for specific cases, such as monitoring triglyceride levels or assessing LDL-C levels in patients with high triglyceride levels 1.
- Triglyceride levels should be interpreted in the context of remnant cholesterol and other lipid parameters to accurately assess ASCVD risk 1.
From the Research
Significance of Lipid Profile in Fasted State
- The significance of a lipid profile in a fasted state has been a topic of debate in recent years, with some studies suggesting that nonfasting lipid profiles are equally effective or even superior for cardiovascular risk prediction 2, 3, 4.
- Historically, lipids and lipoproteins were measured in the fasting state for cardiovascular risk prediction, but this approach has been challenged by studies showing that lipid, lipoprotein, and apolipoprotein concentrations vary minimally in response to normal food intake 3, 4.
- Some studies have found that nonfasting lipid profiles are associated with higher risk of cardiovascular disease, and that reducing levels of nonfasting lipids can reduce the risk of cardiovascular disease 3, 4.
Comparison with Nonfasting Lipid Profiles
- Nonfasting lipid profiles have been shown to be convenient and avoid the risk of hypoglycemia, and can simplify blood sampling for patients, laboratories, and clinicians worldwide 2, 3, 4.
- However, some studies have found that fasting for lipid profile testing is preferred as a conservative model to reduce variability and increase consistency in patients' metabolic status when sampling for lipid testing 5.
- The maximal mean changes for random, nonfasting versus fasting levels are +26 mg/dl for triglycerides, -8 mg/dl for total cholesterol, -8 mg/dl for low-density lipoprotein cholesterol, +8 mg/dl for remnant cholesterol, and -8 mg/dl for non-high-density lipoprotein cholesterol 3, 4.
Clinical Implications
- Several societies' guidelines and statements endorse nonfasting lipid profiles, including those in Denmark, the United Kingdom, Europe, Canada, Brazil, and the United States 2, 3, 4.
- However, some studies suggest that fasting specimen is preferred if cardiovascular risk assessment is based on total cholesterol, LDL cholesterol or non-HDL cholesterol 6.
- Further research is needed to fully understand the implications of nonfasting lipid profiles for cardiovascular risk prediction and to determine the optimal approach for lipid profile testing 2, 3, 5, 4, 6.