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Test Code LEFLU Leflunomide Metabolite (Teriflunomide), Serum

Reporting Name

Leflunomide Metabolite, S

Useful For

Therapeutic monitoring of patients actively taking leflunomide

 

Assessment of elimination in patients requiring enhanced elimination of the drug

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Specimen Type

Serum Red


Specimen Required


Supplies: Sarstedt Aliquot Tube, 5 mL (T914)

Collection Container/Tube:

Preferred: Red top

Acceptable: Serum gel

Submission Container/Tube: Plastic vial

Specimen Volume: 1 mL

Collection Instructions:

1. Draw blood no sooner than 12 hours (trough value) after last dose.

2. Within 2 hours of collection, centrifuge and aliquot serum into a plastic vial.


Specimen Minimum Volume

0.3 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Serum Red Ambient (preferred) 28 days
  Frozen  28 days
  Refrigerated  28 days

Reference Values

Therapeutic: >40 mcg/mL

Elimination: <0.020 mcg/mL

Day(s) Performed

Monday, Wednesday, Friday

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.

CPT Code Information

80193

LOINC Code Information

Test ID Test Order Name Order LOINC Value
LEFLU Leflunomide Metabolite, S 44828-2

 

Result ID Test Result Name Result LOINC Value
60292 Leflunomide Metabolite, S 44828-2

Interpretation

Therapy: clinical targets for serum teriflunomide (leflunomide metabolite) concentrations are still being determined, but levels greater than 40 mcg/mL appear to correlate with better outcome.

 

Elimination: serum concentrations less than 0.020 mcg/mL (20 ng/mL) are preferred to minimize potential teratogenesis for patients considering pregnancy.

Clinical Reference

1. Cannon GW, Kremer JM. Leflunomide. Rheum Dis Clin North Am. 2004;30(2):295-309

2. Chan V, Charles BG, Tett SE. Population pharmacokinetics and association between A77 1726 plasma concentrations and disease activity measures following administration of leflunomide to people with rheumatoid arthritis. Br J Clin Pharmacol. 2005 Sep;60(3):257-264

3. Teschner S, Gerke P, Geyer M, et al. Leflunomide therapy for polyomavirus-induced allograft nephropathy: efficient BK virus elimination without increased risk of rejection. Transplant Proc. 2009;41(6):2533-2538

4. Temprano KK, Bandlamudi R, Moore TL. Antirheumatic drugs in pregnancy and lactation. Semin Arthritis Rheum. 2005;35(2):112-121

5. Hirsch HH, Randhawa PS; AST Infectious Diseases Community of Practice: BK polyomavirus in solid organ transplantation-Guidelines from the American Society of Transplantation Infectious Diseases Community of Practice. Clin Transplant. 2019;33(9):e13528. doi:10.1111/ctr.13528

Report Available

3 to 5 days

Method Name

High-Turbulence Liquid Chromatography Mass Spectrometry (HTLC-MS/MS)

Forms

If not ordering electronically, complete, print, and send a Therapeutics Test Request (T831) with the specimen.