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Mycophenolic Acid

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Also known as: MPA [may be referred to by drug names Mycophenolate mofetil or Mycophenolate sodium or by drug brand names (see MedlinePlus Drug Information) ]
Formal name: Mycophenolic Acid

At a Glance

Why Get Tested?

To determine the concentration of mycophenolic acid (MPA) in the blood in order to monitor levels and prevent toxicity

When to Get Tested?

As soon as mycophenolate therapy begins and whenever the dose is changed; may be ordered frequently at first, then at regular intervals; whenever excess or deficient levels of MPA are suspected

Sample Required?

A blood sample drawn from a vein in your arm

Test Preparation Needed?


The Test Sample

What is being tested?

This test measures the amount of mycophenolic acid in the blood. Mycophenolic acid 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.

Normally, a person's immune system defends the body against infections and can distinguish between self and non-self. The immune system recognizes a transplanted organ as non-self and begins to 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 that suppress the immune system (immunosuppressants) and helps to prevent organ rejection, tissue inflammation, and damage. It acts by inhibiting the formation of an enzyme that is necessary for the production of special immune cells called T-lymphocytes and B-lymphocytes. This inhibition causes a decrease in the immune system function and in antibody production, reducing the body's immune response to transplanted organs or to its own tissues and cells.

Mycophenolate is given to organ transplant recipients in conjunction with other immunosuppressant drugs, such as cyclosporine and tacrolimus. In the treatment of autoimmune disorders, mycophenolate may be used as a single agent (although the person may also be taking other medications). It may be used for treating conditions such as systemic lupus erythematosus (SLE), vasculitis, rheumatoid arthritis, and Crohn disease.

There are two formulations of the drug available, mycophenolate mofetil and mycophenolate sodium. The drug is metabolized by the liver to form first the active mycophenolic acid (MPA) and then the inactive mycophenolic acid glucuronide (MPAG). Cells in the body turn some of the MPAG back into MPA. The level of MPA in the blood rises when MPA is first formed and then again when some of it is re-formed. Most MPAG, and small amounts of MPA, are eliminated from the body in the urine.

Doctors typically give a standard dose of mycophenolate and then monitor its effect clinically. 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. However, the therapeutic range for mycophenolic acid has not yet been fully established and physicians can manage most patients symptomatically.

When the physician chooses to monitor mycophenolic acid levels, the mycophenolic acid blood test is usually measured as a trough level and correlated to clinical side effects. It is timed so that the collection is just prior to the next dose at the drug's lowest concentration in the blood.

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.

The Test

Common Questions

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Article Sources

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NOTE: This article is based on research that utilizes the sources cited here as well as the collective experience of the Lab Tests Online Editorial Review Board. This article is periodically reviewed by the Editorial Board and may be updated as a result of the review. Any new sources cited will be added to the list and distinguished from the original sources used.

Sources Used in Current Review

(December 12 2009). MedlinePlus Drug Information. Mycophenolate. Available online at Accessed August 2011.

(May 20, 2008) Transplant Living. Mycophenolic Acid. Available online through Accessed August 2011.

(©2010) American College of Rheumatology. Practice Management, Mycophenolate. Available online at through Accessed August 2011.

(July 14, 2009) U.S. Food and Drug Administration. Information for Healthcare Professionals: Immunosuppressant Drugs: Required Labeling Changes. Available online st through Accessed July 2011.

Food and Drug Administration. Prescribing Information (Approval 1999). PDF available for download at,021110s043lbl.pdf through Accessed July 2011. 

(©2011) Cleveland Clinic. Transplant programs: Mycophenolate Mofetil. Available online at through Accessed August 2011 .

(©2011) eMedicine Health. Drugs and Medications, Mycophenolate Mofetil. Available online at through Accessed August 2011 .

Clarke, W. and Dufour, D. R., Editors (2006). Contemporary Practice in Clinical Chemistry, AACC Press, Washington, DC. Pg 463.

Tietz Textbook of Clinical Chemistry and Molecular Diagnostics. 4th ed., Burtis CA and Ashwood ER, eds. Philadelphia: W. B. Saunders Company; 2005. Pp 1277-1278.

Jeong H, Kaplan B. Therapeutic Monitoring of Mycophenolate Mofetil. CJASN January 2007 vol. 2 no. 1 184-191. Available online at through Accessed August 2011.

Sources Used in Previous Reviews

Wu, A. (2006). Tietz Clinical Guide to Laboratory Tests, Fourth Edition. Saunders Elsevier, St. Louis, Missouri. Pp 1416-1419.

Bhorade, S. (2006 December, Revised). Medicines for Keeping Your New Heart or Lung Healthy. AST [On-line information]. Accessed on 11/10/07. PDF for download

Aradhye, S. (2006 December, Revised). Medicines for Keeping Your New Kidney Healthy. AST [On-line information]. Accessed on 11/10/07. PDF for download

(2007 August 1). Mycophenolate. MedlinePlus Drug Information [On-line information]. Available online at Accessed on 11/7/07.

Cannon, M. (2006 June, Updated). Mycophenolate Mofetil. ACR [On-line information].  Available online at through Accessed on 11/10/07.

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(© 2007). Mycophenolic Acid. ARUPs Laboratory Test Directory [On-line information]. Available online at through Accessed on 11/10/07.

(© 2007). Mycophenolic Acid and Metabolite. LabCorp [On-line information]. Available online at through Accessed on 11/10/07.

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(2006 August 1). St. John's wort (Hypericum perforatum L.) MedlinePlus Drugs & Supplements [On-line information]. Available online at through Accessed on 11/7/07.

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