What does this LOINC code represent?

This LOINC code identifies a lab observation, measurement, question, or clinical concept in a standardized format.

Is this enough to understand my test result?

No. The code identifies the test or observation, but the interpretation depends on the actual result, reference range, and clinical context.

LOINCActiveOrder

LOINC Code 91139-6: Thiopurine methyltransferase activity panel (RBC)

Name: LOINC Code 91139-6: Thiopurine methyltransferase activity panel (RBC)
Creator: HealthAssure Clinical Team
Published: 2026-05-21T09:00:20.876Z

91139-6 is a LOINC code used to identify Thiopurine methyltransferase activity panel (RBC) in laboratory and clinical observation data. You may see this code in lab systems, lab reports, EHR exports, interoperability feeds, or other structured clinical data exchanges. LOINC codes identify tests, measurements, observations, survey items, and clinical questions in a standardized way. It is associated with the component Thiopurine methyltransferase activity panel. It is commonly used with the system or sample type RBC.

Reviewed by HealthAssure Clinical TeamUpdated 21 May 2026

What is this code?

LOINC codes identify tests, measurements, observations, survey items, and clinical questions in a standardized way. It is associated with the component Thiopurine methyltransferase activity panel. It is commonly used with the system or sample type RBC.

When is it used?

Used in lab systems, EHRs, and clinical data exchange.
May identify a test, observation, survey item, or clinical document request rather than a diagnosis.
Status: ACTIVE
Order vs observation: Order
Panel type: Panel

What it does not mean

The code identifies the observation or test, not the actual result.

Key facts

Thiopurine methyltransferase activity panel - Red Blood Cells

Thiopurine methyltransferase activity panel

This panel includes three terms for different analytes produced by Thiopurine methyltransferase (TPMT) enzyme activity. Levels of the three analytes indicate the level of the patient's TPMT activity, which has clinical implications for the use of thiopurine drugs [PMID23962279]. These tests only indicate the TMPT activity phenotype, not the genotype.

Activ; Actvty; Chemistry; Erythrocytes; Methyl transferase; Movements; Pan; PANEL.CHEMISTRY; Panl; Pnl; Point in time; Random; Red blood cells; Red blood corpusles; TPMT; TPMT activity panel

Where you may see this code

You may see this code in lab systems, lab reports, EHR exports, interoperability feeds, or other structured clinical data exchanges.

Common synonyms

Thiopurine methyltransferase activity panel (RBC)Thiopurine methyltransferase activity panel - Red Blood CellsTPMT activity panel RBCThiopurine methyltransferase activity panelPANEL.CHEMThiopurine methyltransferase activity panel, Red blood cells-

Frequently asked questions

Code details

Code91139-6

SystemLOINC

Display nameThiopurine methyltransferase activity panel (RBC)

DescriptionThiopurine methyltransferase activity panel

Short nameTPMT activity panel RBC

ComponentThiopurine methyltransferase activity panel

Property-

TimingPt

System (specimen)RBC

Scale-

ClassPANEL.CHEM

StatusACTIVE

Order/ObservationOrder

Flags

BillableNo

Valid clinical useNo

Source

SourceLOINC

Version2.82

Releasemain

First released2.65

Last changed2.65

Consumer names

Thiopurine methyltransferase activity panel, Red blood cells

Part names

Thiopurine methyltransferase activity panel-PtRBCPoint in time (spot)Red Blood Cells

About this content

This page is prepared by HealthAssure's clinical team using official coding standards from LOINC. AI tools assist with drafting explanations, which are then reviewed and verified by healthcare professionals for accuracy. This content is for informational purposes and does not replace professional medical advice. Meet our team.