LOINCActiveObservation

LOINC Code 5557-4: HLA-DR Qn (WBC)

5557-4 is a LOINC code used to identify HLA-DR Qn (WBC) 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 HLA-DR. It is commonly used with the system or sample type WBC.

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 HLA-DR. It is commonly used with the system or sample type WBC.

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

  • HLA-DR [Units/volume] in Leukocytes
  • HLA-DR
  • Arbitrary concentration; HLA ANTIGEN; Human Leukocyte Antigen; I3; Leukocytes; Point in time; QNT; Quan; Quant; Quantitative; Random; WBCs; White blood 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

HLA-DR Qn (WBC)HLA-DR [Units/volume] in LeukocytesHLA-DR WBC-aCncHLA-DRHLAHLA-DR, White blood cellsACnc

Frequently asked questions

Code details

Code5557-4
SystemLOINC
Display nameHLA-DR Qn (WBC)
DescriptionHLA-DR
Short nameHLA-DR WBC-aCnc
ComponentHLA-DR
PropertyACnc
TimingPt
System (specimen)WBC
ScaleQn
ClassHLA
StatusACTIVE
Order/ObservationObservation

Flags

BillableNo
Valid clinical useNo

Source

SourceLOINC
Version2.82
Releasemain
First released1.0
Last changed2.69

Consumer names

HLA-DR, White blood cells

Part names

HLA-DRACncPtWBCQnArbitrary ConcentrationPoint in time (spot)White 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.

LOINC Code 5557-4 | HealthAssure