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Paediatric Laboratory Medicine

Mycophenolic Acid (MMF)

Clinical Significance

Mycophenolic acid (MPA), the active metabolite of Mycophenolate Mofetil (MMF), is being used increasingly as an adjunct in immunosuppressant therapy after solid organ transplantation. Its immunosuppressive activity is thought to reside in the inhibition of inosine monophosphate dehydrogenase (IMPDH), leading to a suppression of purine nucleotide synthesis in lymphocytes, thereby suppressing cell mitosis. MPA is converted in the liver mainly to the 7-O-glucuronide metabolite, mycophenolic acid glucuronide (MPAG), which does not have immunosuppressant activity. A second metabolite, acyl glucuronide (AcMPA) does have immunosuppressant activity but is present in much smaller concentrations.

The principal adverse effects of MMF reported in the transplantation studies are gastrointestinal (especially diarrhea and vomiting), haematological and infective.

Test Name

Mycophenolic Acid (MMF)

Alternate Name/ Synonym

Mycophenolate Mofetil (MMF), Myfortic

Test Code


Drug Class



Therapeutic Drug Monitoring - TDM



External Proficiency Testing


Turn Around Time

Daily @ 11:00h

Specimen Type

Plasma (EDTA), Whole Blood (EDTA) may be sent if unable to seperate

Minimum Specimen Requirements

250 uL plasma

Optimal Collection Time

Trough: 0-30 minutes prior to dose


4°C (transport with a cool pack if possible)

Special Requirements

Whole Blood (EDTA) may be sent if unable to separate

Approval is not required

CPT Codes


Shipping and Contact Information

The Hospital for Sick Children
Rapid Response Laboratory
170 Elizabeth Street, Room 3642
Toronto, ON
M5G 2G3
Phone: 416-813-7200
Phone: 1-855-381-3212

Therapeutic Range

Transplant site dependent