Leflunomide Metabolite

Alphabetical Test listing

Leflunomide Metabolite-994

  
Leflunomide Metabolite
  
994
  
LAB994
  
MSO
  
A77/1726
Arava
Teriflunomide
DMARD
  

Leflunomide (Arava®) is a pyrimidine synthesis inhibitor used in the treatment of active rheumatoid arthritis. The drug is available in oral doses containing 10, 20, or 100 mg of active drug. Arava® is an isoxazole immunodulatory agent which inhibits dihydroorotate dehydrogenase (an enzyme involved in de novo pyrimidine synthesis) and has antiproliferative activity. Following oral administration, leflunomide is metabolized to an active metabolite, A77-1726 (teriflunomide), which is responsible for essentially all of its activity in vivo. Peak levels of this metabolite occurred 6 to 12 hours after dosing, with a long half-life (about two weeks).

  
Serum
  
  
1.0 mL
  
0.2 mL
Submission of the minimum volume does not allow for repeat testing
  
  1. Allow sample to clot
  2. Spin and transfer serum or plasma to a Transfer vial/tube with cap - 12mL (LabCorp), labelled as serum or plasma, within 45 minutes of specimen collection.
  
EDTA plasma
  
  

Ambient (preferred) - 30 days

Refrigerated - 30 days

Frozen - 24 months

  

Polymer gel separation tube (SST or PST)

  
NMS Labs (2531SP) via LabCorp (831984)
  
Once per week
  
9 days
  

High Performance Liquid Chromatography/Tandem Mass Spectrometry(LC-MS/MS)

  

Reporting Limit 500 ng/mL

  
80193
  
No
  
Result 38901-5
  
05/24/2019
  
09/07/2022
  
09/07/2022