What does this LOINC code represent?

This LOINC code identifies a lab observation, measurement, question, or clinical concept in a standardized format.

Is this enough to understand my test result?

No. The code identifies the test or observation, but the interpretation depends on the actual result, reference range, and clinical context.

LOINCActiveObservation

LOINC Code 79966-8: Ascending thoracic aorta Diameter during systole by US 2D

Name: LOINC Code 79966-8: Ascending thoracic aorta Diameter during systole by US 2D
Creator: HealthAssure Clinical Team
Published: 2026-05-21T09:00:01.838Z

79966-8 is a LOINC code used to identify Ascending thoracic aorta Diameter during systole 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.systole. It is commonly used with the system or sample type Aorta.thoracic.ascending.

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.systole. It is commonly used with the system or sample type Aorta.thoracic.ascending.

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

Ascending thoracic aorta Diameter during systole by US 2D
Diameter.systole
2D US; AO; Ao asc; Aortic; ATA; CARD.US; CARD.US.DICOM; Cardio; Cardiology; DIA; Diam; diam S; Diam sys; Echography; Heart Disease; Length; Point in time; QNT; Quan; Quant; Quantitative; Random; Sonogram; Sonograph; Sonography; Sys; Syst; Thorax; 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

Ascending thoracic aorta Diameter during systole by US 2DATA Diam sys 2D USDiameter.systoleCARD.US.DICOMLenPtAorta.thoracic.ascending

Frequently asked questions

Code details

Code79966-8

SystemLOINC

Display nameAscending thoracic aorta Diameter during systole by US 2D

DescriptionDiameter.systole

Short nameATA Diam sys 2D US

ComponentDiameter.systole

PropertyLen

TimingPt

System (specimen)Aorta.thoracic.ascending

ScaleQn

MethodUS.2D

ClassCARD.US.DICOM

Example unitscm

StatusACTIVE

Order/ObservationObservation

Flags

BillableNo

Valid clinical useNo

Source

SourceLOINC

Version2.82

Releasemain

First released2.54

Last changed2.67

Part names

Diameter.systoleLenPtAorta.thoracic.ascendingQnUS.2DDiameter during systoleLengthPoint in time (spot)Aorta thoracic ascendingUltrasound 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.