I am blatantly recopying this without permission because this information was burried in the comments thread to this post on cholesterol by Perer Attia. The info is very useful to everyone living outside of the US interested in getting a measurement of their LDL-P.
The NMR scans you are so keen on do not seem to be available in the UK (so I suspect also not in many other places outside the USA): this being the case can you give advice as to how we can make the best use we can of the standard lipid panel, e.g. say a bit more about the usefulness of ratios like that of triglycerides to HDL (giving – with all necessary caveats – broad information about good, bad and middling ratios). – Roger Butler, May 17, 2012
You’re right. Outside of the US the best thing to is have apoB directly measured, as it’s done by a number of labs. This is the best proxy for LDL-P and is more available. – Peter Attia
Note that you will see the test referred to as both “Apo B” and “ApoB” in different places.
So what is ApoB?
The problem with using LDL cholesterol levels to determine heart attack risk is that the test measures only the amount of cholesterol in the LDL cholesterol particles, not the number or size of these particles. Apo B measurements, on the other hand, provide information on the number of LDL cholesterol particles.
Apo B is a protein found on the surface of LDL cholesterol particles. Because each LDL particle contains only one molecule of apo B, the total amount of apo B in the blood is equivalent to the number of LDL cholesterol particles. The size of these particles can sometimes be inferred from the total amount of apo B and the LDL cholesterol level.
For example, people with a higher apo B value than LDL cholesterol value tend to have smaller, denser LDL cholesterol particles. Studies have shown that small, dense LDL cholesterol particles are more strongly associated with heart attack risk than large, “fluffy” LDL cholesterol particles.
Research published in The Lancet reviewed five studies of LDL cholesterol and apo B in nearly 200,000 people. The researchers concluded that high levels of apo B were more strongly linked with future heart attack risk than LDL cholesterol levels.
Apo B is measured with a simple blood test. Proponents of apo B argue that the test is accurate, inexpensive, and does not require fasting, as LDL cholesterol testing usually does. However, the American Heart Association has determined that the evidence to date is not strong enough to recommend that apo B testing become standard procedure.
Even apo B researchers recognize that LDL cholesterol is an important predictor of heart attack risk and suggest that apo B is most helpful for predicting risk in people with normal or low LDL levels but high triglyceride levels. Overall, if one’s LDL cholesterol value is high, an apo B measurement is not necessary.