Serum or plasma free dehydrocholesterol concentration

What Is This Test Measuring?

Dehydrocholesterol is a precursor to cholesterol and is present in both serum and plasma. Free dehydrocholesterol refers to the cholesterol form that is not bound to proteins or other molecules in the blood. This test specifically looks at the unbound form, which can be important for certain metabolic pathways or genetic evaluations.

Why Might You Need This Test?

Your healthcare provider may order this test if you have symptoms or a family history suggestive of conditions like Smith-Lemli-Opitz syndrome (SLOS), a rare genetic disorder affecting cholesterol metabolism. It may also be used in research or specialized diagnostic contexts.

Sample Collection and Preparation

A blood sample is drawn from a vein, typically in your arm. The blood is then processed to separate serum or plasma, which is the clear liquid part of the blood without clotting factors. This sample is sent to a lab for analysis using specialized techniques to measure free dehydrocholesterol concentration.

What Does the Test Result Mean?

Results are reported as a mass concentration (measured in units like micrograms per milliliter or nanograms per milliliter). Interpretation depends on clinical context, including your symptoms, medical history, and any genetic testing results. Your healthcare provider will discuss the meaning of your specific result with you.