Direct HDL is a laboratory test that determines the level of high-density lipoprotein (HDL) cholesterol by measuring directly in human serum, shortening turnaround time and saving labor costs, according to a study published in "Clinical Chemistry."
A direct HDL test can be performed as part of a lipid profile, which checks for HDL, low-density lipoprotein (LDL) cholesterol and triglycerides, according to MayoClinic.com. Cholesterol tests are often performed to determine risk for heart disease.
According to the study in "Clinical Chemistry," the direct HDL test is a homogeneous assay, a laboratory chemical analysis designed to test a homogeneous organic sample, meaning it has a uniform composition and does not need to be separated into specific compounds. This simplifies HDL testing, according to the scientific journal.
Direct HDL measures only HDL, which carries about 1/4 to 1/3 of blood cholesterol. HDL, LDL, triglycerides and another type of cholesterol called Lp(a) make up a total cholesterol count.
HDL cholesterol is called “good” cholesterol because it carries cholesterol away from arteries and back to the liver, where it's broken down and eliminated, according to the American Heart Association.
Average HDL cholesterol levels range from 40 to 50mg/dL for men, according to the American Heart Association. For women, they range from 50 to 60mg/dL. A level of 60mg/dL or higher is beneficial for both women and men, according to the association. The higher the level, the better, MayoClinic.com information states.