Cardiologist Dr. Paul D. Thompson, MD, lists the blood tests he orders for people with high cholesterol and explains what each one adds, from thyroid and blood sugar checks to lipoprotein(a) and a simple count of harmful particles.
Blood Tests for High Cholesterol: Lipid Panel, Lipoprotein(a), Thyroid, A1c, and ApoB
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- The basic cholesterol panel
- Lipoprotein(a) testing
- Thyroid function
- Glucose and hemoglobin A1c
- ApoB and the number of particles
- Full Transcript
The basic cholesterol panel
The basic cholesterol panel is the starting point for everybody, cardiologist Dr. Paul D. Thompson, MD, tells Dr. Anton Titov, MD. It includes total cholesterol and what he calls the good, the bad, and the ugly: HDL is the good cholesterol, triglycerides are the bad, and LDL is the ugly.
Lipoprotein(a) testing
Lipoprotein(a) is a test Dr. Thompson thinks everybody should have. His reason is that a person whose cholesterol levels look good can still be at risk of heart disease with a terrible lipoprotein(a) level. In his closing list, he says measuring it avoids giving false reassurance that everything is okay.
Thyroid function
Thyroid function, measured with TSH, is another test he orders. Very low thyroid levels can cause very high cholesterol levels, and he says he has seen cholesterol levels of 400 in a patient whose only problem was low thyroid function.
Because low thyroid can be silent, he says a thyroid measurement is one of the first things to get when cholesterol is high, to make sure the thyroid is not causing the problem.
Glucose and hemoglobin A1c
Glucose and hemoglobin A1c tests look for diabetes, and he considers the A1c more important. He explains that glucose in the bloodstream binds to proteins, including hemoglobin, so the hemoglobin A1c gives an estimate of where glucose has been over the past three months.
A single glucose value, he notes, could be good now or very high after a big meal, and a fasting glucose level does not show that. He describes the A1c as a test that has been watching you for three months.
ApoB and the number of particles
ApoB is his answer to the question of fancy lipid testing, such as particle size. He says what happens to the arteries depends on the number of bad particles: atherosclerosis develops faster with more particles, just as a chemical reaction in high school chemistry goes faster with more reagent.
Every bad particle carries one ApoB, so an ApoB level shows whether there are too many particles, without the need for an expensive specialized test. In a short self-quiz, he notes that LDL and VLDL particles each carry one ApoB, while HDL, a good particle, carries none. An ApoB level, he says, shows how many particles are floating around trying to give you a heart attack.
Full Transcript
Dr. Anton Titov, MD: Cholesterol blood tests, which blood tests a patient with high cholesterol needs. On your blog, you described the cholesterol panel as the baseline test. You also measure thyroid function, lipoprotein little a, and apolipoprotein B. You wrote that lipoprotein little a is largely inherited, so one test is usually enough. Professor Thompson, which blood tests should a patient with high cholesterol ask for? Who would benefit from a lipoprotein little a test?
Dr. Paul D. Thompson, MD: So that is a great question. What sort of test should you get? So everybody really should have the basic cholesterol levels.
Dr. Paul D. Thompson, MD: So total cholesterol; your ugly cholesterol, the LDL; your good cholesterol, the HDL; and the bad cholesterol, the triglycerides. In addition, I think everybody should have a lipoprotein little a measurement, because if your cholesterol levels are good but you have a terrible lipoprotein(a), you are at risk of heart disease. So you ought to get that measured.
Dr. Paul D. Thompson, MD: Now, the other thing you need to get is a thyroid level with TSH. Very low thyroid levels can cause very high cholesterol levels. I have seen cholesterol levels of 400, and the only problem with the patient is that their thyroid function was low.
Dr. Paul D. Thompson, MD: In thyroid disease, low thyroid can be silent. You do not know you have got it. So if your cholesterol level is high, one of the first things you want to do is get a thyroid measurement.
Dr. Paul D. Thompson, MD: The other thing you want to get is a glucose measurement to look for diabetes, and what is called a hemoglobin A1c. The hemoglobin A1c is more important. Glucose, if your glucose is in the bloodstream, it binds to things.
Dr. Paul D. Thompson, MD: It binds to proteins, and one of the proteins it binds to is hemoglobin. Now, the hemoglobin A1c gives you an estimate of where your glucose has been over the past three months. I could get a good glucose now.
Dr. Paul D. Thompson, MD: I could have a big meal; my glucose could go very high. You do not know from a fasting glucose level. The hemoglobin A1c is more, "I have been watching you for three months, and here is your level." So a hemoglobin A1c is very important.
Dr. Paul D. Thompson, MD: I get the basic cholesterol levels, the good, the bad, and the ugly; the lipoprotein(a); a thyroid function; a glucose; a hemoglobin A1c. Now let us talk about whether you need fancy lipid testing, do you need particle size and all that sort of stuff. What happens to your arteries depends on the number of bad particles you have.
Dr. Paul D. Thompson, MD: Atherosclerosis, the development of cholesterol in your arteries, athero, remember, means artery, sclerosis means harder, atherosclerosis and how rapidly that occurs depends on how many particles there are. You remember high school chemistry, where you could make the reaction, the chemical reaction, go faster with more reagent? Well, the reagent for the chemical reaction of atherosclerosis in your artery, the reagent is how many particles you have.
Dr. Paul D. Thompson, MD: How many molecules did you have for that science project in high school? How many particles you have for the science project of your arteries. So I like to get an ApoB measurement.
Dr. Paul D. Thompson, MD: Why? Every bad particle has one ApoB. You do not need to get a $400 fancy test to measure your number of particles.
Dr. Paul D. Thompson, MD: A cheap test, an ApoB: if your ApoB is high, you know you have too many particles. Every bad particle has one ApoB. Let me quiz myself.
Dr. Paul D. Thompson, MD: "Dr. Thompson, how many ApoBs are on an LDL particle?" One.
Dr. Paul D. Thompson, MD: "Dr. Thompson, how many ApoBs are on a VLDL?" Very low density lipoprotein particle.
Dr. Paul D. Thompson, MD: One, right? Because it is a bad particle.
Dr. Paul D. Thompson, MD: "Dr. Thompson, how many ApoBs are on the HDL particle?" Because it is a good particle, zero.
Dr. Paul D. Thompson, MD: So you know how many bad particles you have when you get an ApoB measurement. So: standard cholesterol levels; thyroid function, to make sure it is not causing the problem; lipoprotein(a), so we do not give you false reassurance that everything is okay.
Dr. Paul D. Thompson, MD: And an ApoB level, to know how many particles are floating around trying to give you a heart attack.