Test Code TPMRBC Thiopurine Methyltransferase, RBC Phenotype

Important Note

Phenotype test to assess risk for severe myelosuppression with standard dosing of thiopurine drugs. Testing should be performed prior to initiation of thiopurine therapy. For therapy optimization or toxicity evaluation, order Thiopurine Metabolites

Additional Codes

92066

Methodology

Enzymatic/Quantitative Liquid Chromatography-Tandem Mass Spectrometry

Specimen Type

Whole Blood

Preferred Collection Container

PINK

Collection Volume

5.0 mL

Minimum Collection Volume

3.0 mL

Collection Instructions

Routine venipuncture

Transport

Refrigerated

Rejection Criteria

Gel separator tubes. Specimens collected in sodium fluoride/potassium oxalate (gray). Hemolyzed, frozen, or room temperature specimens.

Specimen Storage and Stability

Ambient: 3 hours; Refrigerated: 6 days; Frozen: Unacceptable

Turn Around Time

4-6 days

Test Alias

92066, TPMT, TPMT Erythrocytes, TPMT-RBC, TPMT Enzyme

CPT Coding

84433

EPIC Code

LAB2448A

Acceptable Collection Container

LAV (venipuncture), PINK (K2EDTA) OR 6ML LAV (K2EDTA)

Testing Volume