The Test Sample
What is being tested?
Mycophenolic acid (MPA) is the active metabolite of mycophenolate, a drug that is primarily given to people who have had a heart, kidney, or liver transplant to help prevent rejection and secondarily to people with a variety of autoimmune disorders. This test measures the amount of mycophenolic acid in the blood.
Normally, a healthy immune system distinguishes the body's own healthy tissue (self) from threats such as viruses, bacteria, and parasites (non-self). However, the immune system recognizes a transplanted organ as non-self and may attack it. In the case of autoimmune disorders, the immune system mistakenly targets the body's own cells and tissues, causing damage and inflammation.
Mycophenolate belongs to a group of drugs called immunosuppressants that suppress the immune system and helps to prevent organ rejection, tissue inflammation, and damage. Mycophenolate acts by inhibiting formation of an enzyme necessary to produce special immune cells called T-lymphocytes and B-lymphocytes. Inhibiting lymphocyte formation decreases both immune system function and antibody production, reducing the body's immune response to transplanted organs or to its own tissues and cells.
Organ transplant recipients receive mycophenolate in conjunction with other immunosuppressant drugs such as cyclosporine and tacrolimus. Autoimmune disorder patients may be prescribed mycophenolate as a single agent, although they may take other medications. It has been used to treat lupus (especially with symptoms of kidney disease), rheumatoid arthritis, vasculitis, inflammatory bowel disease such as Crohns disease, inflammatory eye diseases including iritis and scleritis, and some other kidney or skin disorders.
Mycophenolate, like most immunosuppressants, must be maintained within a narrow therapeutic range. If the level is too low, organ rejection may occur; if it is too high, then the person may develop toxicity. The mycophenolic acid blood test uses blood samples collected when the drugs are at their lowest, typically just prior to the next dose. Such levels are called trough levels and they are correlated to clinical side effects.
How is the sample collected for testing?
A blood sample is obtained by inserting a needle into a vein in the arm.
NOTE: If undergoing medical tests makes you or someone you care for anxious, embarrassed, or even difficult to manage, you might consider reading one or more of the following articles: Coping with Test Pain, Discomfort, and Anxiety, Tips on Blood Testing, Tips to Help Children through Their Medical Tests, and Tips to Help the Elderly through Their Medical Tests.
Another article, Follow That Sample, provides a glimpse at the collection and processing of a blood sample and throat culture.
Is any test preparation needed to ensure the quality of the sample?
No test preparation is needed.