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Mycophenolic Acid (MPA) and Metabolite

CPT 80180
Synonyms
  • Myfortic®

Test Details

Methodology

Liquid chromatography/tandem mass spectrometry (LC/MS-MS)

Result Turnaround Time

3 - 5 days

Turnaround time is defined as the usual number of days from the date of pickup of a specimen for testing to when the result is released to the ordering provider. In some cases, additional time should be allowed for additional confirmatory or additional reflex tests. Testing schedules may vary.

Related Documents

Use

Monitor therapeutic levels; evaluate toxicity

Limitations

This test was developed and its performance characteristics determined by LabCorp. It has not been cleared or approved by the Food and Drug Administration.

Footnotes

1. Deters M, Koal T, Kirchner G, Resch K, Kaever V. Influence of cyclosporine on the serum concentration and biliary excretion of mycophenolic acid and 7-O-mycophenolic acid glucuronide. Ther Drug Monit. 2005 Apr; 27(2):132-138. 15795641
2. Sankatsing SU, Hoggard PG, Huitema AD, et al. Effect of mycophenolate mofetil on the pharmacokinetics of antiretroviral drugs and on intracellular nucleoside triphosphate pools. Clin Pharmacokinet. 2004; 43(12):823-832. Erratum: 2005;44(12):1246. 15355127

Custom Additional Information

Mycophenolic acid (MPA) is the active metabolite of the prodrug, mycophenolate mofetil (MMF). Absorption of the prodrug is rapid following oral administration to the extent that detectable levels are not seen. Similar effects are observed after cessation of IV administration. Once formed, MPA undergoes metabolism to form the pharmacologically inactive phenolic glucuronide metabolite, MPAG. In vivo, MPAG is converted to MPA via enterohepatic recirculation, which results in a secondary peak in the plasma concentration time profile.1 MPA and MPAG are 92% and 87% protein bound, respectively, at usual clinical concentrations.

Recent reports have suggested that there could be a potential pharmacokinetic drug interaction between MPA and the calcineurin inhibitors. Several groups have observed that, in combination with cyclosporine, MPA serum concentrations are lower, and the MPAG serum concentrations are higher than in combination with tacrolimus.1

MPA has also been implicated as an adjuvant with highly active antiretroviral therapy (HAART) due to the selective inhibition of the conversion of inosine 5′-monophosphate to xanthosine 5′-monophosphate by the enzyme, inosine 5′-monophosphate dehydrogenase (IMPDH). Blocking this enzyme in lymphocytes depletes guanosine triphosphate (GTP) and deoxyguanosine triphosphate (dGTP) pools. This depletion of dGTP pools inhibits the activation of T lymphocytes, thereby limiting the availability of target cells for HIV.2

Specimen Requirements

Specimen

Serum or plasma

Volume

1.2 mL

Minimum Volume

0.3 mL (Note: This volume does not allow for repeat testing.)

Container

Red-top tube or lavender-top (EDTA) tube

Collection Instructions

Transfer separated serum or plasma to a plastic transport tube.

Stability Requirements

Temperature

Period

Room temperature

14 days

Refrigerated

14 days

Frozen

14 days

Freeze/thaw cycles

Stable x3

Storage Instructions

Room temperature

Causes for Rejection

Gel-barrier tube

LOINC® Map

Order Code Order Code Name Order Loinc Result Code Result Code Name UofM Result LOINC
716795 Mycophenolic Acid and Metabo. 87432-1 716796 Mycophenolic Acid ug/mL 23905-3
716795 Mycophenolic Acid and Metabo. 87432-1 716797 Mycophenolic Acid Glucuronide ug/mL 23906-1
Order Code716795
Order Code NameMycophenolic Acid and Metabo.
Order Loinc87432-1
Result Code716796
Result Code NameMycophenolic Acid
UofMug/mL
Result LOINC23905-3
Order Code716795
Order Code NameMycophenolic Acid and Metabo.
Order Loinc87432-1
Result Code716797
Result Code NameMycophenolic Acid Glucuronide
UofMug/mL
Result LOINC23906-1