Lipids and Lipoproteins in Clinical Chemistry

The recommended fasting period before a blood test to measure total cholesterol (TC) and high-density lipoprotein (HDL-C) levels is 12 hours.

High-density lipoprotein (HDL-C) levels can be measured even without fasting before a blood test.

Triglyceride levels can be measured without fasting. However, it's important to note that the triglyceride levels decrease significantly by almost 50% when a person goes from an upright to supine position.

Squeezing or excessive probing of a vein during blood collection can lead to hemoconcentration. This is because it forces fluid out of the blood vessels, concentrating the blood components like red blood cells.

The National Cholesterol Education Program (NCEP) recommends that patients sit for at least 5 minutes before a blood test to ensure accurate lipid measurements.

The recommended fasting period before a blood test to measure triglycerides (TAG) and low-density lipoprotein (LDL-C) levels is at least 12 hours.

Estrogen, a female sex hormone, can have significant effects on lipoprotein levels. It increases the levels of high-density lipoprotein (HDL) and decreases the levels of low-density lipoprotein (LDL).

Total cholesterol (TC) and high-density lipoprotein (HDL-C) levels can be measured without fasting before a blood test.

Postural changes, specifically going from an upright to a supine position, can decrease triglyceride (TAG) levels by almost 50%.

Tourniquets should not be applied for longer than a minute or two, if possible, to avoid errors in blood collection and potential discomfort for the patient.