Leflunomide Metabolite (Teriflunomide) LC-MS/MS, Serum
Test Overview
Clinical Utility
Leflunomide is rapidly and extensively metabolized to teriflunomide,which is the active form of the medication. Therapeutic monitoring of teriflunomide is important to ensure adequate dosage. It is recommended that women of childbearing potential who discontinue leflunomide therapy undergo the cholestyramine drug elimination procedure.This procedure includes verification that plasma levels of teriflunomide are less than 20 ng/mL by two separate tests at least 14 days apart.
Method
Liquid chromatography-tandem mass spectrometry (LC-MS/MS)
Result Included
Teriflunomide
Specimen
Specimen Type
Avoid gel separator tubesSerum
Plasma (Na Heparin)
Plasma (Li Heparin)
Volume
Sample Volume
1.0 mL
Minimum Volume
0.5 mL
Specimen Comment
Avoid gel separator tubes.
Collection & Handling
Handling Information
Store and send cold or frozen.
Stability
| Ambient | Refrigerated | Frozen |
|---|---|---|
| 5 days | 14 days | 30 days |
Rejection Criteria
| Criteria | Specification |
|---|---|
| Specimen | Gel-separator tubes |
Performance & Interpretation
Turnaround Time
10 days
Results
-
Leflunomide Metaboliteng/mLTherapeutic: See note
Elimination: <20
Comment
Mean steady state plasma concentrations of teriflunomide from patients on daily dosages of 5, 10, or 25 mg of leflunomide were 8,800, 18,000 and 63,000 ng/mL, respectively.
Referral Location
Out-of-Country
Interface & Setup
HL7 Interface Codes
| Order Code | Result Name | Result Codes | Units |
|---|---|---|---|
| LEFLUN | TERIFLUNOMIDE | 38058 | ng/mL |
Test Version
Last Updated
2023-05-26