LOINCObservation

LOINC Code 8129-9: CD4 cells/CD8 Cells (Bld) [# ratio]

8129-9 is a LOINC code used to identify CD4 cells/CD8 Cells (Bld) [# ratio] 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.CD4/Cells.CD8. It is commonly used with the system or sample type Bld.

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.CD4/Cells.CD8. It is commonly used with the system or sample type Bld.

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: DEPRECATED
  • Order vs observation: Observation

What it does not mean

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

Key facts

  • Deprecated CD4 cells/CD8 Cells [# Ratio] in Blood
  • Cells.CD4/Cells.CD8
  • Blood; CD4 Cells; CD8 Cells; Cell; CELL MARKERS; Cellularity; Helper T cells; Inducer T cells; L3T4; Leu2; Leu-2; Leu3; Leu-3; Number ratio; Point in time; QNT; Quan; Quant; Quantitative; Random; Suppressor T cells; T4; T-4; T8; T-8; Tsuppressor; W3/25; WB; Whole blood

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

CD4 cells/CD8 Cells (Bld) [# ratio]Deprecated CD4 cells/CD8 Cells [# Ratio] in BloodDeprecated CD4 Cells/CD8 Cells BldCells.CD4/Cells.CD8CELLMARKCD4 cells/CD8 Cells, BloodNRto

Frequently asked questions

Code details

Code8129-9
SystemLOINC
Display nameCD4 cells/CD8 Cells (Bld) [# ratio]
DescriptionCells.CD4/Cells.CD8
Short nameDeprecated CD4 Cells/CD8 Cells Bld
ComponentCells.CD4/Cells.CD8
PropertyNRto
TimingPt
System (specimen)Bld
ScaleQn
ClassCELLMARK
StatusDEPRECATED
Order/ObservationObservation

Flags

BillableNo
Valid clinical useNo

Source

SourceLOINC
Version2.82
Releasemain
First released1.0h(2)
Last changed2.70

Consumer names

CD4 cells/CD8 Cells, Blood

Part names

Cells.CD4/Cells.CD8NRtoPtBldQnNumber RatioPoint in time (spot)Blood

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.

LOINC Code 8129-9 | HealthAssure