Answer
LDL-C is a calculated value and is part of the lipid profile recommended by the ATP III of the National Cholesterol Education Program (2001).
Blood is drawn after a 9-hour to 12-hour fast. The rationale behind fasting is to eliminate chylomicrons in the blood. If a patient doesn’t fast, it can cause an underestimation of the LDL value.
The sample is usually drawn in either a red-top or green- top tube and is part of the lipid profile. Early morning specimens are preferable. Patients should have been on a stable diet for 3 weeks for the results to be accurate.
Also note that in cases of recent myocardial infarction or stroke, lipid levels may be lower than what they actually are, and they normalize in 12 weeks. Checking a lipid panel 12 weeks after the acute insult is wise.
