LOINCActiveObservation

LOINC Code 17988-7: Right atrial Apical 4 chamber [Area] by US 2D

17988-7 is a LOINC code used to identify Right atrial Apical 4 chamber [Area] by US 2D 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 Apical 4 chamber. It is commonly used with the system or sample type Heart.atrium.right.

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 Apical 4 chamber. It is commonly used with the system or sample type Heart.atrium.right.

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
  • Method: US.2D

What it does not mean

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

Key facts

  • Right atrial Apical 4 chamber [Area] by US 2D
  • Apical 4 chamber
  • 2D US; A4C; ap4; Apical 4CH; Atrial; CARD.US; Cardiac; Cardio; Cardiology; Echography; Heart Disease; Hrt; Point in time; QNT; Quan; Quant; Quantitative; R; RA; RAA; Random; RT; Sonogram; Sonograph; Sonography; ULS; Ultrasound; Ultrasound - 2-dimensional

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

Right atrial Apical 4 chamber [Area] by US 2DRA Apical 4CH Area 2D USApical 4 chamberCARD.USAreaPtHeart.atrium.right

Frequently asked questions

Code details

Code17988-7
SystemLOINC
Display nameRight atrial Apical 4 chamber [Area] by US 2D
DescriptionApical 4 chamber
Short nameRA Apical 4CH Area 2D US
ComponentApical 4 chamber
PropertyArea
TimingPt
System (specimen)Heart.atrium.right
ScaleQn
MethodUS.2D
ClassCARD.US
Example unitscm2
StatusACTIVE
Order/ObservationObservation

Flags

BillableNo
Valid clinical useNo

Source

SourceLOINC
Version2.82
Releasemain
First released1.0l
Last changed2.48

Part names

Apical 4 chamberAreaPtHeart.atrium.rightQnUS.2DPoint in time (spot)Heart.atrium RightUltrasound 2D

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.