LOINC Code 21563-2: Thiopurine methyltransferase (RBC) [Catalytic activity/Vol]
21563-2 is a LOINC code used to identify Thiopurine methyltransferase (RBC) [Catalytic activity/Vol] 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. It is commonly used with the system or sample type RBC.
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. 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: Both
What it does not mean
- The code identifies the observation or test, not the actual result.
Key facts
- Thiopurine methyltransferase [Enzymatic activity/volume] in Red Blood Cells
- Thiopurine methyltransferase
- Catalytic Concentration; Chemistry; Erythrocytes; Methyl transferase; Point in time; QNT; Quan; Quant; Quantitative; Random; Red blood cells; Red blood corpusles; TPMT; UniversalLabOrders
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
Frequently asked questions
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.