LOINCActiveObservation

LOINC Code 78176-5: Aorta root Diameter by US 2D

78176-5 is a LOINC code used to identify Aorta root Diameter 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 Diameter. It is commonly used with the system or sample type Aorta.root.

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 Diameter. It is commonly used with the system or sample type Aorta.root.

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

Aorta root Diameter by US 2D
Diameter
On 2D echo, the diameter of the aortic root should be measured at the maximal diameter of the sinuses of Valsalva. [PMID25559473]
2D US; AO; AO root; Aortic; CARD.US; Cardio; Cardiology; DIA; Diam; Echography; Heart Disease; Length; Point in time; QNT; Quan; Quant; Quantitative; Random; 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

Aorta root Diameter by US 2DAO root Diam 2D USDiameterCARD.USLenPtAorta.root

Frequently asked questions

Code details

Code78176-5
SystemLOINC
Display nameAorta root Diameter by US 2D
DescriptionDiameter
Short nameAO root Diam 2D US
ComponentDiameter
PropertyLen
TimingPt
System (specimen)Aorta.root
ScaleQn
MethodUS.2D
ClassCARD.US
Example unitscm
StatusACTIVE
Order/ObservationObservation

Flags

BillableNo
Valid clinical useNo

Source

SourceLOINC
Version2.82
Releasemain
First released2.54
Last changed2.54

Part names

DiameterLenPtAorta.rootQnUS.2DLengthPoint in time (spot)Aorta rootUltrasound 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.

LOINC Code 78176-5 | HealthAssure