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Test Code LEFLU Leflunomide Metabolite (Teriflunomide), Serum

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
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

CPT Code Information

80193

Report Available

3 to 5 days

Specimen Retention Time

14 days

Reject Due To

Gross hemolysis OK
Gross lipemia OK
Gross icterus OK