How to Interpret Cholesterol Test Results

Before we get into the big job of interpreting cholesterol numbers, let’s review what cholesterol actually is. Cholesterol is cholesterol: a waxy steroid of fat that serves as an essential structural component of cellular membranes and in the production of steroid hormones, vitamin D, and bile acids. Contrary to what the terminology indicates, there’s actually only one “type” of cholesterol in the human body, and it’s called, quite simply, cholesterol. What we think of when we use the word “cholesterol” is actually a lipoprotein – a fatty conglomerate of protein and lipids that delivers cholesterol and fat and fat-soluble nutrients to different parts of the body. It’s not just free cholesterol floating around in your blood; it’s cholesterol bound up by lipoproteins. So LDL, HDL, VLDL, all those (in)famous measurements we get at the doctor’s office are just different types of lipoproteins. They’re not actually cholesterol. I discussed this briefly a couple years back, and there’s always Griff’s big primer in the forum, so take the time to go check out both. And also take a peak at The Definitive Guide to Cholesterol for review. Okay, let’s talk about the most commonly bandied-about cholesterol numbers: LDL-C and HDL-C. What do they really mean? What are they actually measuring? To understand what these numbers mean, let’s play the freeway analogy game. Both LDL-C and HDL-C, the standard, basic readings you get from the lab, do not reflect the number of LDL or HDL particles – the number of lipoproteins – in your serum. Instead, they reflect the total amount of cholesterol contained in your LDL and HDL particles. Hence, the “C” in LDL/HDL-C, which stands for “cholesterol.” Measuring the LDL/HDL-C  and then making potentially life-changing health decisions based on the number is like counting the number of people riding in vehicles on a freeway to determine the severity of traffic. It’s data, and it might give you a rough approximation of the situation, but it’s not as useful as actually counting the number of vehicles. A reading of 100 could mean you’re dealing with a hundred compact cars, each carrying a single driver, or it could mean you’ve got four buses carrying 25 passengers each. Or it could be a couple buses and the rest cars. You simply don’t know how bad (or good) traffic is until you get a direct measurement of LDL and HDL particle number. Say you go ahead and get those particle numbers directly measured. You’re still limited, because that is just a single datapoint from a specific time in your life/day/week. Analogies are fun and helpful, I think, so let’s take this traffic and freeway stuff further. To get an accurate idea of traffic, you need constant updates, right? Imagine you counted the number of cars on the freeway at 12:05 on a Saturday afternoon four weeks ago. That’s great, but what does it tell you about traffic at 5 PM on a Thursday? Even though it’s the same stretch of asphalt/artery, we can’t divine much at … Continue reading How to Interpret Cholesterol Test Results