LOINCActive

LOINC Code 54121-9: Twin Family member

54121-9 is a LOINC code used to identify Twin Family member 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 Twin. It is commonly used with the system or sample type ^Family member.

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 Twin. It is commonly used with the system or sample type ^Family member.

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

What it does not mean

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

Key facts

  • Twin Family member
  • Twin
  • Arbitrary; Fam Mem; Ordinal; Point in time; QL; Qual; Qualitative; Random; Screen; Survey; SURVEY.USSGFHT

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

Twin Family memberTwinSURVEY.USSGFHTArbPt^Family memberOrd

Frequently asked questions

Code details

Code54121-9
SystemLOINC
Display nameTwin Family member
DescriptionTwin
ComponentTwin
PropertyArb
TimingPt
System (specimen)^Family member
ScaleOrd
ClassSURVEY.USSGFHT
StatusACTIVE

Flags

BillableNo
Valid clinical useNo

Source

SourceLOINC
Version2.82
Releasemain
First released2.26
Last changed2.30

Part names

TwinArbPt^Family memberOrdArbitraryPoint in time (spot)

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 54121-9 | HealthAssure