A B C D E F G H I J K L M N O P Q R S T U V W X Y Z #

Thiopurine Metabolites

Message
This test should only be performed for patients currently on thiopurine therapy. This therapy includes administration of azathioprine or mercaptopurine. This test may not be useful in patients with autoimmune hepatitis


Test Code
LAB00118


Alias/See Also
LAB00118
LabCorp TC: 503800

THIOPU,AZATH ,MAILFX,MMP ,METABO,ES,TGN
 


CPT Codes
80299

Includes

Thiopurine Metabolites
6-TGN
6-MMPN


Preferred Specimen
WHOLE BLOOD


Minimum Volume
3 mL


Instructions
Collect blood in lavender-top (EDTA) tube only. Gently invert to mix. Submit whole blood refrigerated. Do not separate specimen. Do not freeze


Specimen Stability
Refrigerated up to 8 days Room temperature up to 1 day Frozen unacceptable


Limitations
This test should only be performed for patients currently on thiopurine therapy. This therapy includes administration of azathioprine or mercaptopurine. This test may not be useful in patients with autoimmune hepatitis.



Clinical Significance
LabCorp's Thiopurine Metabolites assay measures the red-cell concentration of 6-MMP (formed from 6-MP by thiopurine methyltransferase) and also measures the concentration of the resulting 6-TG after removal of the mono-, di-, or tri-phosphates from the various 6-thioguanine nucleotides. Once thiopurine therapy has been undertaken and an equilibrated drug level is achieved (usually 3 to 6 months),literature suggest that the measurement of thiopurine metabolites is warranted in the following situations: 1. Unresponsive patients to rule out a) patient non-compliance (low 6-MMP and low 6-TG in those not taking medications), b) those with diversion of metabolites away from 6-TG production (low 6-TG and normal or increased 6-MMP), c) those with refractory to treatment (adequate 6-TG but lack of clinical response), and d), those with excessive 6-MMP (or increased 6-MMP:6-TG ratio with adequate 6-TG) leading to increased hepatotoxicity. 2. Clinically responsive patients to look for excessive levels of either 6-MMP or 6-TG to avoid toxicity.


Performing Laboratory
**Testing is performed at Esoterix Endocrinology Laboratory via LABCORP. **This test includes Serial Monitoring**



The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.