Laboratory: Clinical Biochemistry  (SPECIAL CHEMISTRY)
Test Name:
Test Code: MYPA
Clinical Information:
Description: Mycophenolic acid (MPA) is an active metabolite of mycophenolate mofetil (MMF), an immunosuppressant medication used to prevent transplant rejection. It is typically used in combination with calcinurine inhibitors and steroids. MPA is a selective, noncompetitive, and reversible inhibitor of inosine monophosphate dehydrogenase (IMPDH), an enzyme in de novo synthesis of guanosine.
Test Indications: Monitoring of MPA levels can be useful immediately after therapy is initiated (up to 3 weeks) or upon major changes in health status.
It is important to note that effective therapeutic range depends on numerous factors, including type of transplant, time post-transplant, patient's clinical status (e.g. organ function), and co-medication.
Collection Devices:
Gel tubes are not acceptable. Serum (red top, no gel) is acceptable.
Specimen Required:
Plasma: 1.0 mL
Pediatric Plasma: 0.3 mL

Collection Information: Optimum time to collect 30-60 min before next dose (trough) at steady-state (3-5 days on the same dose).
Special Processing: Include on requisition form date and time of last dose prior to sample collection
Specimen Stability: 
Ambient: 8 hours
Refrigerated: 14 days
Frozen: 11 months at -20 C

Shipping & Storage: Separate plasma and aliquot. Store and send refrigerated or frozen to HSC Clinical Chemistry - MS5. Avoid repeat freeze-thaw cycles.
Reference Values:
Reference Intervals: 
Therapeutic range (trough):  1.0 - 3.5 mg/L
Toxic range: >25.0 mg/L
*Trough: just before the next regular dose; steady-state: 3-5 days at the same dose 
Specimens collected outside of steady-state trough period in the dosing cycle are likely to have higher MPA levels and trough therapeutic range should not be applied.
Method of Analysis: LC-MS/MS (Laboratory Developed Test)
Once Per Week
Test is performed at HSC every Friday. For same day analysis, samples must be received at HSC prior to 12 pm on Friday.
See Also:
More Information:
References: Bergan S et al. Personalized Therapy for Mycophenolate: Consensus Report by the International Association of Therapeutic Drug Monitoring and Clinical Toxicology. Ther Drug Monit. 2021 Apr 1;43(2):150-200.