Direct measurement of TC, HDL, and triglyceride. Divide triglyceride by 5 to estimate VLDL. add VLDL and HDL and subtract from TC to obtain LDL. It was my understanding that LabCorp would do direct measurements of all, and include IDL but such is not the case. Maybe it's moot; maybe the longstanding current method is sufficient for dx purposes and assessing risk.
My doctor seems obsessed with doing blood tests. Every 6 months. The tests for the last 2 years are now on a patient portal. I got curious about cholesterol recently and couldn't find it at all on any of the reports. Maybe it is coded as something else besides HDL and LDL? Or maybe it isn't as important as it used to be? He's never asked me to fast.
Fasting used to be for blood sugar levels, but now they look at your A1C, which somehow reflects long-term sugar levels. I'm constantly "pre-diabetic," but as I tell my doctor, I'm also "pre-dead," so which am I supposed to worry about? When I look online for my cholesterol results, they are in a test result named "Lipid Panel." If you are on statins, they are supposed to do a semi-annual Liver Enzyme test. My doctors have been imperfectly diligent over the years in the 6 month blood work routine. Cholesterol is manufactured in your liver, so that's what the statins act on. But your liver's main duty is to produce the enzymes that break down toxins in your system so those toxins can be excreted (your liver is not a filter as some believe it to be...it makes cleansing enzymes.) Since statins might damage your liver, doctors are supposed to measure its enzyme production level twice a year as a precaution.
Thanks, John. I found it now. Under Lipid Panel. How did I miss it? Looks like this lab does it by subtraction also. Btw, 20 years ago total cholesterol of 197 would have scared the heck out of me, but the doctor never mentioned it.
I just looked and my lab work does not measure VLDL. I cannot test Boris' statement for me. I wonder if there has to be concern in order to request that additional measurement. I used to get it with my old [now retired] doctor. My most recent report indicates that 200mg/dl Total Cholesterol is the threshold for concern these days. I recall the threshold used to be 180, but my memory may be flawed. My numbers are real good because when I had a small [presumed] stroke in January of 2020, they upped my Lipitor dosage as standard practice for supposed stroke patients. They get put on 40mg Lipitor even if they don't otherwise need statins and have never been on them. At 40mg, Lipitor (unlike other statins) reduces the stickiness of platelets. I had been pretty well cholesterol-controlled at 20mg. As an aside, when the cardio guy told me he was not sure I actually had a stroke, I told him to cut my Lipitor dosage back to 10mg so I don't trash my liver. He said that the damage risk is introduced when you take any amount of statin, and that increases in dosage do not equate to a like-kind increased risk. Kinda good to know if your doctor wants to increase your dosage. There is one odd thing I remember, because a friend had this issue: women tend to have higher HDL levels than men because of estrogen, but they are also at risk to having too much "good cholesterol." Notice that HDL has a Target Range with an upper limit to it (my report puts it at 30 - 65), not a minimum above which anything is better. A quick internet search says a 2017 study brought this to light (increases risk of death from all causes), but my friend had then-known heart problem risks due to extremely high HDL. This was in the early 90s. It's just another data point to be aware of...
Divide your triglycerides by five and assume the result to be VLDL. Then add the assumed VLDL to HDL and subtract that figure from total cholesterol and see if the result is what they report for LDL. If not, maybe your lab directly measures LDL.
The above calc gives me 92.4 Reported LDL is 95 It's close, but sounds directly measured since it ain't exact.
I thought the same thing. And there's no amount of adjusting the reported base numbers to allow for their having been rounded that would bump my result that much. I could raise it to 93.49 by using the most extreme decimal numbers that would have rounded to the whole numbers shown on the report. I just took a look on the web, and University of Virginia Health Systems/UVA Hospital have their own lab (UVA Medical Lab.) I take it you have run this calc on your numbers and the result supports your assertion.
Absolutely, since the late 80s, covering several lab companies. I was clued in way back in the 80s when a lab printed "calc" behind the LDL and VLDL values. I figured Tri-Gs figured into the calculation somehow because one of their degradation products is VLDL which in turn yields LDL. Trial & error ensued until the divisor 5 worked, each time it was tried. I mentioned this to several MDs including personal and a few at work. They were generally non-committal and shrugged. For whatever all of the above is worth. I'd still like to get some answers about IDL's. Where do they fit in? Are they ignored?
Interesting stuff. I have never heard of IDLs. A cursory read says that they are formed when HDL and LDL degrade, and further reading states that IDLs are then either taken up (removed from the bloodstream) by the liver or converted back into LDL. I wonder if there's research going on to figure out how to actually cause HDL to degrade into IDL, which would concurrently raise LDL...assuming that all the theories about "good" and "bad" are valid.
I guess that the med. community is satisfied that what they have now suffices for assessing risk until other measures are discovered. Perhaps IDL % is so small as to be insignificant and ignored when directly measuring TC regardless of whether the body kicks IDLs out or they return to being bad guys. A PhD biochemist is probably the one to talk to rather than the MDs.
It seems to me that IDL is some type of transition state. Perhaps it might be an indicator of causal issues, but you can't treat something that is ephemeral.
These tests are meant to be diagnostic primarily. Maybe if they study IDL further, they can predict in the individual case whether it's going to be booted out or revert to evil. It doesn't seem that it's of any great concern to them right now.
We're both old enough to recall when all of this research and knowledge were supposed to work magic in our lives. And maybe it has. Life expectancy is nearly at 80 years of age. As long as they stop pretending that every new "discovery" is an absolute truth, then I'm fine with the industry. Personally, I believe very little of the conclusions that are put forth, although the data is sure interesting.