What Laboratory Numbers Are Right For Me? Part 1

What Laboratory Numbers Are Right For Me?  Part 1

People following cholesterol values often ask what numbers are "right" for them. The answer is determined by the following questions.

Question 1 - What lipid / lipoprotein values should be used as goals?
Question 2 - What is the person's cardiovascular risk status (high-risk, moderate-risk, low-risk)?
Question 3 - What goals are appropriate for the level of cardiovascular risk present?

Each of these questions will be addressed in individual posts.

Question 1 - What lipid / lipoprotein values should be used as goals?

The first and most important goal is LDL. In general, the higher the cardiovascular risk, the lower the LDL target. Hence, specific LDL goals depend on a person's cardiovascular risk status.

Somewhat more complicated is the question of which measure of LDL quantity should be used as our target.

Most people are unaware that low-density lipoprotein (LDL), a particle that carries cholesterol, can be estimated by measuring cholesterol or determined by measuring the number of LDL particles (LDL-P). Cholesterol measures used to estimate LDL include LDL cholesterol (LDL-C), as well as total cholesterol minus HDL cholesterol (aka, non-HDL cholesterol [non-HDL-C]).

Because the amount of cholesterol in lipoprotein particles is highly variable (some LDL particles carry less than half the expected amount of cholesterol), LDL-P can be more than double the expected amount in people with very little cholesterol carried in their LDL particles. Thus, cholesterol measures of LDL (LDL-C or non-HDL-C) and particle number measures of LDL (LDL-P) may agree or disagree.

Multiple studies consistently show that when LDL-C or non-HDL-C (cholesterol estimates of particles) disagree with LDL-P (true measure of LDL particles), cardiovascular risk tracks with LDL-P, NOT cholesterol values (LDL-C or non-HDL-C).

As a result, expert panels now advise that when LDL-C and non-HDL-C are near or at goal physicians should check LDL-P values. If LDL-P is high, then the person actually has a HIGH LDL despite a good cholesterol value. In such a case, treatment should be tailored to ensure the patient reaches LDL-P targets, not just cholesterol goals.

Triglycerides are a second target of therapy. Values less than 150 are appropriate for all patients.

HDL is a controversial target of therapy. Some experts advocate HDL cholesterol values greater than 40 in men and greater than 50 in women.