LOINC

LOINC Code 5518-6: CD66c Qn (WBC)

5518-6 is a LOINC code used to identify CD66c 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 CD66c. 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 CD66c. 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: DEPRECATED

What it does not mean

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

Key facts

  • Deprecated CD66c cells/100 cells in Blood
  • CD66c
  • Arbitrary concentration; CELL MARKERS; Leukocytes; NCA; NCA-50/90; 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

CD66c Qn (WBC)Deprecated CD66c cells/100 cells in BloodDeprecated CD66c WBC-aCncCD66cCELLMARKCD66c, White blood cellsACnc

Frequently asked questions

Code details

Code5518-6
SystemLOINC
Display nameCD66c Qn (WBC)
DescriptionCD66c
Short nameDeprecated CD66c WBC-aCnc
ComponentCD66c
PropertyACnc
TimingPt
System (specimen)WBC
ScaleQn
ClassCELLMARK
StatusDEPRECATED

Flags

BillableNo
Valid clinical useNo

Source

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

Consumer names

CD66c, White blood cells

Part names

CD66cACncPtWBCQnArbitrary 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 5518-6 | HealthAssure