Vitamin A test

Alternative names:

retinol test

What the risks are:

Risks associated with venipuncture are slight:

• excessive bleeding
• fainting or feeling lightheaded
• hematoma (blood accumulating under the skin)
• infection (a slight risk any time the skin is broken)
• multiple punctures to locate veins

Special considerations:

A vitamin A tolerance test is performed by giving the patient large doses of vitamin A and then measuring the serum (blood) levels 4 or 5 hours later.

Veins and arteries vary in size from one patient to another and from one side of the body to the other. Obtaining a blood sample from some people may be more difficult than from others.