When a doctor draws blood to test for LDL and HDL what else do they test for?

Lipids. This is usually part of a lipid profile --- total cholesterol, hdl, ldl, & triglycerides.
Depends on Doctor. Lipoproteins are complex particles which carry fat molecules in the water outside cells. Generally, LDL particles deliver fat molecules into cells; HDL particles can remove fat molecules from cells. Ldl is always in nmol/l, best <700, HDL in µmol/l, best large-hdl >10 see NMR particle test. Cholesterol, a fat molecule made by every single animal cell, is ~30% of all fat molecules in all membranes.

Related Questions

Total chol 215 trig 69 HDL 82 LDL 119 healthy male 65 blood press under control. Take 500mg niacin twice a day. Doctor suggests statins. Suggestions?

Judgement call. Your high HDL is very good. Ldl not bad. What other risk factors do you have? Smoker? Diabetes? Hypertension? Family history? Obesity? Sedentary? Although Niacin does nice things to your lipids, the outcomes studies suggest that statins prevent heart disease better. The risk of side effect from statin is lower than niacin. On balance, i tend to agree with your doctor. Read more...
Why niacin. As monotheist when HDL already excellent ...Most men your age have heart disease...Look into a coronary calcium screening to see if focus should be on ldl. Read more...