A standard lipid panel reports total cholesterol, HDL cholesterol, triglycerides and LDL cholesterol. Many reports add non-HDL cholesterol. Three of those are measured in the lab. The other two are usually worked out with arithmetic.
Knowing which lines are measured and which are calculated explains most of the confusion people have with their results, including why LDL can look different from one lab to the next. This guide goes through the report line by line.
Key takeaways
- LDL cholesterol is usually an estimate built from the other lines, not a direct measurement.
- That estimate becomes less reliable when triglycerides are high or LDL is very low.
- Non-HDL cholesterol is total minus HDL, and it sidesteps the LDL estimate altogether.
- Eating beforehand shifts triglycerides the most and the cholesterol lines only a little.
- A lipid panel does not include ApoB or Lp(a), which have to be ordered separately.
The lines at a glance
| Line on the report | What it is | Measured or calculated |
|---|---|---|
| Total cholesterol | Cholesterol in all particles combined | Measured |
| HDL cholesterol | Cholesterol in HDL particles | Measured |
| Triglycerides | The main fat carried in the blood | Measured |
| LDL cholesterol | Cholesterol in LDL particles | Usually calculated |
| Non-HDL cholesterol | Total minus HDL | Calculated |
This article explains what each line is. What level is right for you depends on your overall risk and not on one universal cut-off. Our guide to LDL levels by risk, linked at the end, covers that.
Total cholesterol
Total cholesterol adds up the cholesterol in every kind of particle: the ones that form plaque and the HDL particles that do not. That mix is why it is a blunt number. Two people can share a total of 210 and have quite different risk.
It still earns its place, because heart risk calculators use it together with HDL. Just do not read much into total cholesterol in isolation.
LDL cholesterol: calculated or direct
LDL cholesterol is the line most treatment decisions refer to, and on most reports it is not measured. Look for "calc" or "calculated" beside it.
The classic method is the Friedewald equation. It takes total cholesterol, subtracts HDL, then subtracts an estimate of the cholesterol in triglyceride-rich particles. The Friedewald equation gets that estimate by dividing triglycerides by a fixed factor of 5.1
The weak point is the fixed factor. In real blood samples that relationship varies with triglyceride and cholesterol levels. When researchers checked estimated LDL against directly measured LDL in more than 1.3 million people, the Friedewald result put those with triglycerides below 400 mg/dL in the correct guideline category 85.4% of the time, compared with 91.7% for a newer method with an adjustable factor.1
The errors are not spread evenly. Calculated LDL is less accurate in people with a low LDL level or with triglycerides of 400 mg/dL or higher.2 Above that triglyceride level many labs will not report a calculated LDL at all.
This is why your report may name a method such as Martin-Hopkins or Sampson-NIH. These are updated equations meant to hold up better across a wider range. Some labs also offer a direct LDL test that measures it chemically. If your LDL jumped between two labs, a change in method is one possible reason.
HDL cholesterol
HDL cholesterol is the cholesterol carried in HDL particles, which do not build plaque. A low value is a warning sign. A European expert consensus advises labs to flag HDL at or below 40 mg/dL.3
Low HDL often travels with high triglycerides and insulin resistance. A very high HDL should not be read as extra protection, though. We explain why in is higher HDL always better?
Triglycerides
Triglycerides are fat, not cholesterol. They are the form in which your blood carries fat from food and from the liver. This is the line that responds most to what you ate and drank recently.
The same European consensus advises flagging triglycerides at 150 mg/dL or higher on a fasting sample, and at 175 mg/dL or higher on a non-fasting one.3 Our guide to triglycerides and heart risk covers the categories and causes.
Non-HDL cholesterol
Non-HDL cholesterol is the simplest calculation on the page: total cholesterol minus HDL. What is left is the cholesterol in every plaque-forming particle, not only LDL.
It has two advantages. It does not depend on the triglyceride-based estimate, so it stays dependable when triglycerides are high. And it can be read from a non-fasting sample. If your report does not print it, you can work it out yourself. Our separate guide to non-HDL cholesterol is linked below.
Fasting or not
For years everyone was told to fast. That advice has loosened. The 2018 US cholesterol guideline says screening can be done with a fasting or a non-fasting sample.4
The reason is that ordinary meals change the results less than people expect. A European consensus statement put the largest average changes after habitual meals at about 26 mg/dL higher for triglycerides and about 8 mg/dL lower for total and LDL cholesterol, with HDL cholesterol unaffected.3
That group suggested a fasting repeat when non-fasting triglycerides come back very high, above about 440 mg/dL. Your clinician may also ask for a fasting sample when other fasting tests are drawn at the same visit.
That is the case at our clinic. We ask you to fast for 10 to 12 hours before labs, for the best accuracy on the lipid and insulin results. See fasting before heart labs for the practical details.
What the panel leaves out, and where Cardio Res-Q fits
A lipid panel measures cholesterol content. It does not count particles, and it does not include Lp(a). Both need separate tests. Our article on normal cholesterol but still at risk explains why that gap matters.
The Cardio Res-Q Comprehensive Assessment ($775) measures ApoB, Lp(a), hs-CRP, homocysteine, insulin, glucose and A1c, along with the Cleveland Heart cardiac panel and Dr. Varano's clinical evaluation. The Enhanced Assessment ($999) adds a CIMT ultrasound and a coronary calcium score. If you have a recent lipid panel, bring it, and ask our team what else is included. You can book from the Cardio Res-Q program page.
Are You a Candidate for Cardio Res-Q?
Three quick questions about the risk factors we screen for. Your answers stay between you and the clinic.
Frequently asked questions
Why does my report say "LDL calc"?
Because the lab estimated LDL cholesterol from your total cholesterol, HDL and triglycerides instead of measuring it. This is standard practice and works well for most people. It is less dependable when triglycerides are high or LDL is very low.
Why is my LDL blank or marked "unable to calculate"?
Usually because your triglycerides were too high for the equation to be trusted, typically 400 mg/dL or more. Your clinician can order a direct LDL test, rely on non-HDL cholesterol, or repeat the panel fasting.
Which number on the panel matters most?
For treatment decisions, LDL cholesterol and non-HDL cholesterol carry the most weight. HDL and triglycerides add context, especially about insulin resistance. No single line should be read without the others or without your overall risk.
What is the VLDL line on some reports?
It is an estimate of the cholesterol in triglyceride-rich particles, worked out from your triglyceride result. It is the same estimate that is subtracted to get calculated LDL, so it is not an independent measurement.
Related reading
This article is for general education and is not medical advice. Decisions about testing and medication should be made with your clinician. If you have chest pain or other symptoms of a heart attack, call 911.
