How to understand your blood test results for cholesterol


If you ever took a blood test and wondered how to interpret it, this will be a quick and easy guide.

Let’s take my readings as an example. Cholesterol is measured in two main units:

  1. mmol/L (millimoles per liter) - used in Europe, UK, Canada, Australia, Asia. It counts the number of cholesterol molecules in blood.
  2. mg/dL (milligrams per deciliter) - used mainly in the USA. It measures the weight of cholesterol in blood.
I am in Europe so see my results below in mmol/l. As you see my cholesterol is really high.

Cholesterol 7,17 mmol/l
Cholesterol HDL 2,09 mmol/l
Cholesterol LDL 4,68 mmol/l
Cholesterol non HDL 5,08 mmol/l
Triglycerides 0,87 mmol/l


The first line is total cholesterol 7,17. If we sum up HDL and non HDL (2nd and 4th line) we get the same number.


HDL (High-Density Lipoprotein) – is called “good cholesterol” because it carries excess cholesterol from the blood and arteries back to the liver to be removed, which helps protect the heart. For me it is 2,09. Non HDL is every type of cholesterol you want to have lower, but most importantly LDL.

LDL (Low-Density Lipoprotein) – is called “bad cholesterol” because it carries cholesterol from the liver to the arteries, where it can build up as plaque and increase heart-disease risk if levels are high.For me it is 4,68.

In essence HDL and LDL are the most important readings in your test. Often people say that just looking at total cholesterol is not enough, you need to check for good and bad cholesterol. Total cholesterol alone doesn’t give the full picture of heart health.


How high is too high? The table below shows you optimal/borderline/high values for both mg/dL and mmol/L .

Lipid type Normal (mg/dL / mmol/L) Borderline High
LDL cholesterol <100 /<2.6 130-159 / 3.4-4.1 ≥160 / ≥4.1
HDL cholesterol ≥60 / ≥ 1.55 40-59 / 1.0-1.54 <40 / 1.0
Total cholesterol <200 / <5.2 200-239 / 5.2-6.2 ≥240 / ≥6.2
Triglycerides <150 / <1.7 150-199 / 1.7-2.2 ≥200 / ≥2.3

One comment about triglycerides. They are a type of fat (lipid) in your blood that your body uses for energy. Think of them as fuel your body stores for later in simplified words. High levels of triglycerides increase risk of heart disease and pancreatitis.

Let’s take a hypothetical example. We have 2 patients, one eats an extremely healthy diet. The second patient eats a lot of ultra processed foods. Both go to gym and have similar activity levels but patient 1 has a higher level of cholesterol. Why?

Because diet, exercise and weight are not the only factors affecting cholesterol. Age, gender, genetics and certain medical conditions also significantly affect cholesterol levels.

Now lastly, why would you care about cholesterol at all? Because too much bad cholesterol (LDL) or triglycerides and too little good cholesterol (HDL) can silently clog arteries and increase your risk of heart attack or stroke. High cholesterol is very common worldwide. About 1 in 3 adults has elevated total cholesterol, even in people who feel healthy.