Leflunomide Metabolite
Test Summary
Leflunomide is an immunosuppressant medication used in the treatment of rheumatoid arthritis. Leflunomide is rapidly and extensively metabolized to teriflunomide, which is the active form of the medication. Steady state plasma concentrations in patients receiving recommended daily dosages: up to 63,000 ng/mL. It is recommended that all women of childbearing potential who discontinue leflunomide and women receiving treatment who wish to become pregnant 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.
Aliases
- N/A
Specimen Collection
Special Instructions
N/A
Preferred Specimen
1 mL serum collected in a red-top tube (no gel)
Minimum Volume
0.5 mL
Instructions
N/A
Patient Preparation
N/A
Storage
N/A
Transport Temperature
Room temperature
Specimen Stability
- Room temperature: 5 days
- Refrigerated: 14 days
- Frozen: 30 days
Limitations
N/A
Other Acceptable Specimens
Plasma collected in: Sodium heparin (green-top) or lithium heparin (green-top)
Unacceptable Specimens
Serum separator tubes (SST)
Order Code
LEFMET
EPIC (Premier) Code
LAB5161
Includes
N/A
CPT Code
- 80193
Billing Code
- 700000
CPT Statement
Methodology
Chromatography/Mass Spectrometry
FDA Status
This test was developed and its analytical performance characteristics have been determined by Quest Diagnostics. It has not been cleared or approved by the U.S. Food and Drug Administration. This assay has been validated pursuant to the CLIA regulations and is used for clinical purposes.
Physician Attestation of Informed Consent
N/A
Testing Laboratory
Quest Diagnostics Nichols Institute Valencia
27027 Tourney Road
Valencia CA, 91355
27027 Tourney Road
Valencia CA, 91355
Reference Range
See Laboratory Report
Setup Schedule / Expected Turnaround Time
Tuesday, Thursday, Saturday; Report available: 3 - 5 days
Specimen Collection
Special Instructions
N/A
Preferred Specimen
1 mL serum collected in a red-top tube (no gel)
Minimum Volume
0.5 mL
Instructions
N/A
Patient Preparation
N/A
Storage
N/A
Transport Temperature
Room temperature
Specimen Stability
- Room temperature: 5 days
- Refrigerated: 14 days
- Frozen: 30 days
Limitations
N/A
Other Acceptable Specimens
Plasma collected in: Sodium heparin (green-top) or lithium heparin (green-top)
Unacceptable Specimens
Serum separator tubes (SST)
Result Information
Methodology
Chromatography/Mass Spectrometry
Testing Laboratory
N/A
Reference Range
See Laboratory Report
Setup Schedule / Expected Turnaround Time
Tuesday, Thursday, Saturday; Report available: 3 - 5 days