A lipid panel is a blood test that measures the fats and fat-carrying particles in your bloodstream. It’s one of the most common screening tools for heart disease risk, and it typically reports four numbers: total cholesterol, LDL cholesterol, HDL cholesterol, and triglycerides. If you’ve been told you need one, or you’re trying to make sense of results you just received, here’s what each number means and what counts as normal.
The Four Numbers on a Lipid Panel
Three of the four values are measured directly from your blood sample. The fourth, LDL cholesterol, is usually calculated from the other three.
- Total cholesterol is the sum of all cholesterol carried in your blood. A desirable level is generally under 200 mg/dL. Between 200 and 239 is considered borderline high, and 240 or above is high.
- LDL cholesterol is often called “bad” cholesterol because it’s the main particle that deposits cholesterol into artery walls. It’s the primary number most clinicians use to guide treatment decisions. Optimal is under 100 mg/dL for most people, though targets vary based on your overall risk.
- HDL cholesterol works in the opposite direction, carrying cholesterol back to the liver for disposal. Higher is better here. For men, HDL shouldn’t drop below 40 mg/dL; for women, the floor is 50 mg/dL. Levels between 60 and 80 are considered protective against heart disease.
- Triglycerides are the form your body uses to store energy in fat cells. A healthy level is under 150 mg/dL. Between 150 and 199 is borderline high, 200 to 499 is high, and anything at or above 500 is very high, which carries its own set of risks including inflammation of the pancreas.
How LDL Is Calculated (and When It’s Wrong)
Rather than measuring LDL directly, most labs use a formula that subtracts HDL and a fraction of your triglycerides from your total cholesterol. This works well for the majority of people, but the formula becomes unreliable when triglycerides are very high, roughly above 400 mg/dL. At that level, the standard calculation can underestimate your actual LDL, sometimes enough to change treatment decisions.
People with diabetes or those already taking cholesterol-lowering medications can also see larger gaps between calculated and directly measured LDL. If your triglycerides run high or your results seem inconsistent with your risk factors, your provider may order a direct LDL measurement instead.
Non-HDL Cholesterol and Ratios
Some lab reports include a fifth number: non-HDL cholesterol. This is simply your total cholesterol minus your HDL. It captures all the cholesterol particles that can contribute to artery damage, including LDL and a few other types like VLDL. For people with elevated triglycerides, non-HDL can be a more reliable indicator of risk than LDL alone.
Another useful metric is the total cholesterol to HDL ratio. You divide your total cholesterol by your HDL number. Most doctors want this ratio below 5 to 1, and a ratio below 3.5 to 1 is considered very good. A high ratio typically means you have too much harmful cholesterol relative to the protective kind.
Do You Need to Fast?
For decades, a 9 to 12 hour fast was standard before any lipid panel. That’s shifting. Major guidelines, including those from the Canadian Cardiovascular Society, now recommend nonfasting lipid panels as the default for both baseline and follow-up testing. Eating a meal raises triglycerides modestly but doesn’t meaningfully change total cholesterol, LDL, or HDL in most people.
Fasting is still recommended if you have a history of triglyceride levels above about 400 mg/dL, which applies to roughly 2% of the population. If a nonfasting test comes back with very high triglycerides, your provider will likely ask you to repeat it after fasting to get a more accurate reading. For everyone else, a nonfasting draw is perfectly reliable and far more convenient.
When and How Often to Get Tested
The 2026 ACC/AHA guidelines recommend screening children once between ages 9 and 11, because early signs of artery damage can appear that young. For adults without known lipid problems, screening starts at age 19 and repeats every five years. As you get older or accumulate risk factors like high blood pressure, diabetes, smoking, or a family history of early heart disease, testing becomes more frequent.
If you’re on cholesterol-lowering medication, expect a lipid panel 4 to 12 weeks after starting or changing your dose to see how well it’s working. Once your levels are stable, annual testing is typical.
What Can Throw Off Your Results
A lipid panel is a snapshot, and several things can temporarily shift the picture. Acute illnesses, especially infections or inflammatory conditions, tend to lower LDL and HDL while raising triglycerides. A blood draw taken during or shortly after an illness may not reflect your usual levels. Most providers will wait a few weeks after recovery before drawing a lipid panel they plan to act on.
Alcohol intake within 24 hours of your test can raise triglycerides noticeably. Intense exercise in the days before your draw can temporarily improve your numbers. Even the lab itself introduces minor variability: differences in equipment calibration and reagent formulations between labs mean that repeating the same blood sample at two facilities could yield slightly different results. None of this means the test is unreliable. It just means a single borderline result is best confirmed with a second draw rather than treated as a definitive verdict.
Genetic variation also plays a role. People naturally carry different proportions of LDL subtypes, and some lab methods interact unevenly with those subtypes. This is one reason your doctor looks at the full pattern of your results, your health history, and your risk factors rather than making decisions based on any single number in isolation.