For many of us with heart disease, our knowledge of blood tests is limited to knowing our cholesterol and that higher is “bad” and lower is “good.” But even the so-called “standard lipid panel” is really several tests that each provide useful information and potential drawbacks. You may also be missing out on newer tests that just might more accurately tell you how to win your battle against heart disease.
If you wish to practice what I call “Informed Self-Directed Healthcare” (ISH), or taking your health into your own hands, then enjoy this short primer on understanding heart health blood tests.
The standard lipid panel
The standard lipid panel measures your LDL (bad) cholesterol, HDL (good) cholesterol, total cholesterol, and your triglycerides (a blood fat that the body uses for many purposes). American Heart Association (AHA) guidelines call for:
- Total cholesterol: less than 200 mg/dL
- LDL cholesterol: less than 100 mg/dL
- HDL cholesterol: greater than 40 mg/dL for men and 50 mg/dL for women
- Triglycerides: less than 150 mg/dL
Note that “mg/dL” (milligrams per deciliter) is a unit of measure that determines the weight of all the cholesterol or triglyceride particles in a given volume of blood. A milligram is approximately 2.2 millionths of a pound (a very small weight) and a deciliter is a little over four-tenths of a cup (0.4222675284 to be precise).
Therefore, a total cholesterol of 200 mg/dL equals about one one-thousandth of a pound of cholesterol per cup of blood (0.0010628613903055 pounds per cup for the number geeks like me). There are other ways to measure these particles (by size and total number of particles for example) that may provide better information (more on this later).
The standard lipid panel is a useful device because it is simple, inexpensive, and widely known and understood by most doctors. But it is also fraught with many problems. Part of the problem is that it is based on a calculation developed by Dr. Friedewald more than 40 years ago. The process measures your total cholesterol, HDL cholesterol, and triglycerides and calculates your LDL cholesterol. That’s right, the most important number and the one used to prescribe cholesterol-lowering medications is a calculation and not a direct measurement—and it can be off by 50 percent or more.
Tests that measure cholesterol by particle number and size
Recall that the standard lipid panel measures cholesterol by weight for a given volume (just like pounds per cup for example). Now, imagine I told you that I had a cup of marbles that weighed one pound. It doesn’t tell you very much about those marbles does it? Do I have one large marble weighing one pound in that cup? Sixteen smaller marbles weighing one ounce each? Or maybe I have one million marbles about the size and weight of grains of sand?
It turns out that for cholesterol, for both LDL (bad) and HDL (good), size and number matter. In both cases, bigger size is better, and for LDL cholesterol, a smaller particle number is better (less than 1000 nmol/L).
Modern science has now classified LDL cholesterol into two major size groups (and many more groups as we continue the research) called “Pattern A” (larger, less dense, and healthier particles) and “Pattern B” (smaller, more dense, and less healthy particles). Therefore, a blood test revealing you have 100 mg/dL of LDL cholesterol may by a wonderful number if it is composed of a mix of particles that trend toward the larger Pattern A type, but it can be potentially deadly if they are mostly small Pattern B type.
HDL cholesterol behaves similarly. It is believed that one of the functions of HDL cholesterol is to remove the cholesterol that LDL cholesterol puts into our arteries leading to heart disease. That is why we are starting to hear about the importance of our LDL-to-HDL ratio. It makes sense that it is just as important to raise the rate at which cholesterol is taken out of our arteries as it is to lower the rate at which we put it in. The bad news is that it has proven far easier to lower LDL than it is to raise HDL, but many new and promising HDL-raising treatments are currently in the pipeline (one of them, a form of synthetic super-HDL, actually reduced plaques in as little as six weeks). Research suggests that the larger HDL particles (a subtype known as HDL2b) do a better job of removing cholesterol.
Ask your doctor if you might benefit from one of these more advanced tests. Your drug, diet, and supplement treatment could be greatly enhanced just by knowing this critical information. Here is a list of companies that offer such tests.
Other important lipid tests
In addition to testing for small LDL particles, I would also consider asking your doctor to test for a lipid particle known as “lipoprotein(a)” or “Lp(a).” Lp(a) has recently been discovered to be an independent risk factor for heart attacks, especially in young and middle-aged adults. It has sometimes been called “super-bad cholesterol” because even small amounts (above 30 mg/dL or 70 nmol/L) can lead to heart disease even if your other cholesterol numbers are good.
Genetic tests are beginning to explode upon the health scene with the power to greatly improve our understanding of the specific causes of heart disease in each person and tailor individual treatments rather than rely on “what works” for most people. Many of these genetic tests are expensive and, even if you find a genetic cause, there may be little you can do to treat it.
A recent exception is the ApoE gene. It is a rather inexpensive and readily available test that actually provides data that heart disease sufferers can use to tailor treatments, especially diet and lifestyle. ApoE genes come in three types or “alleles”—ApoE2, ApoE3, and ApoE4. ApoE3 is considered “normal” with different risks inferred by ApoE2 and ApoE3. You inherit one allele from each parent so you may have a combination of any two of the three (including a double dose of the same allele).
Compared to "standard" treatment recommendations for the "normal" apo E3 patients, and considering associated cardiovascular disease risk marker abnormalities, personalized recommendations for lifestyle changes and pharmacotherapy may be modified with apo E2 and apo E4 genotype patients.
- Responds particularly well to statins
- Moderate alcohol intake may have positive effects
- Low-fat diet may increase small dense LDL
- Moderate (35 percent) fat dietary restriction recommended
- Normal treatment guideline recommendations
- Preventive (25 percent) fat or moderate (35 percent) fat dietary restriction determined by overall lipid profile
- Limited responsiveness to statins
- Alcohol intake may have negative effects
- Very low (20 percent) fat dietary restriction recommended
So, there you have it—some practical guidelines to using blood tests to help better understand and treat your heart disease. I would encourage those who have additional questions to join in or start new discussions on the site.
Medical science is moving at a blinding pace, and there is a lot more to talk about than what conveniently fits in one article. But, that’s the good news!