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Test Code LAB2034 Leflunomide Metabolite (Teriflunomide), Serum

Additional Codes

LEFLU

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
Medical University of South Carolina Note:

On-campus collections: Tube to 99 or deliver to University Extension Hospital Room EH318 
Send serum in plastic vial, Ambient.
 
Off-campus collections: Centrifuge and aliquot within 2 hours. Specimen to be stored/transported at Ambient temp. 

Reference Values

Therapeutic: >40 mcg/mL

Elimination: <0.020 mcg/mL

Day(s) Performed

Monday, Wednesday, Friday

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.

Method Description

Serum samples are diluted in an aqueous solution containing deuterated teriflunomide as an internal standard. This is injected onto a liquid chromatography system with Cohesive turboflow to separate the drug from serum components and analyzed by negative-ion mode tandem mass spectrometry.(Unpublished Mayo method)

Report Available

3 to 5 days

Specimen Retention Time

14 days

Reject Due To

Gross hemolysis OK
Gross lipemia OK
Gross icterus OK

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.

Secondary ID

60292