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.

LOINCActiveObservation

LOINC Code 42620-5: Terminal deoxyribonucleotidyl transferase cells/Cells (BM)

Name: LOINC Code 42620-5: Terminal deoxyribonucleotidyl transferase cells/Cells (BM)
Creator: HealthAssure Clinical Team
Published: 2026-05-21T08:59:28.128Z

42620-5 is a LOINC code used to identify Terminal deoxyribonucleotidyl transferase cells/Cells (BM) 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 Cells.terminal deoxyribonucleotidyl transferase/Cells. It is commonly used with the system or sample type Bone mar.

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 Cells.terminal deoxyribonucleotidyl transferase/Cells. It is commonly used with the system or sample type Bone mar.

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: Observation

What it does not mean

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

Key facts

Terminal deoxyribonucleotidyl transferase cells/cells in Bone marrow
Cells.terminal deoxyribonucleotidyl transferase/Cells
BM; BON; Bone marrow; Cell; CELL MARKERS; Cellularity; MAR; Marrow (bone); minimal angle of resolution; Minimum angle of resolution; Number fraction; Percent; Point in time; QNT; Quan; Quant; Quantitative; Random; TdT; TdT Cells

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

Terminal deoxyribonucleotidyl transferase cells/Cells (BM)Terminal deoxyribonucleotidyl transferase cells/cells in Bone marrowTdT Cells NFr MarCells.terminal deoxyribonucleotidyl transferase/CellsCELLMARKTerminal deoxyribonucleotidyl transferase cells/cells, Bone marrowNFr

Frequently asked questions

Code details

Code42620-5

SystemLOINC

Display nameTerminal deoxyribonucleotidyl transferase cells/Cells (BM)

DescriptionCells.terminal deoxyribonucleotidyl transferase/Cells

Short nameTdT Cells NFr Mar

ComponentCells.terminal deoxyribonucleotidyl transferase/Cells

PropertyNFr

TimingPt

System (specimen)Bone mar

ScaleQn

ClassCELLMARK

Example units%

StatusACTIVE

Order/ObservationObservation

Flags

BillableNo

Valid clinical useNo

Source

SourceLOINC

Version2.82

Releasemain

First released2.16

Last changed2.79

Consumer names

Terminal deoxyribonucleotidyl transferase cells/cells, Bone marrow

Part names

Cells.terminal deoxyribonucleotidyl transferase/CellsNFrPtBone marQnNumber FractionPoint in time (spot)Bone marrow

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.