LOINCActiveBoth

LOINC Code 5164-9: Fc fragment Ab Qn (S)

5164-9 is a LOINC code used to identify Fc fragment Ab Qn (S) 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 Fc fragment Ab. It is commonly used with the system or sample type Ser.

Reviewed by HealthAssure Clinical TeamUpdated 25 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 Fc fragment Ab. It is commonly used with the system or sample type Ser.

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

  • Fc fragment Ab [Units/volume] in Serum
  • Fc fragment Ab
  • ABS; Aby; Antby; Anti; Antibodies; Antibody; Arbitrary concentration; Autoantibodies; Autoantibody; Fc Frg; Frag; Fragments; Point in time; QNT; Quan; Quant; Quantitative; Random; Serology; Serum; SR

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

Fc fragment Ab Qn (S)Fc fragment Ab [Units/volume] in SerumFc Frg Ab Ser-aCncFc fragment AbSEROFc fragment antibody, BloodACnc

Frequently asked questions

Code details

Code5164-9
SystemLOINC
Display nameFc fragment Ab Qn (S)
DescriptionFc fragment Ab
Short nameFc Frg Ab Ser-aCnc
ComponentFc fragment Ab
PropertyACnc
TimingPt
System (specimen)Ser
ScaleQn
ClassSERO
StatusACTIVE
Order/ObservationBoth

Flags

BillableNo
Valid clinical useNo

Source

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

Consumer names

Fc fragment antibody, Blood

Part names

Fc fragment AbACncPtSerQnArbitrary ConcentrationPoint in time (spot)Serum

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 5164-9 | HealthAssure