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 77909-0: Aortic valve Effective regurgitant orifice area by US.doppler+Calculated by PISA method

Name: LOINC Code 77909-0: Aortic valve Effective regurgitant orifice area by US.doppler+Calculated by PISA method
Creator: HealthAssure Clinical Team
Published: 2026-05-21T08:59:58.755Z

77909-0 is a LOINC code used to identify Aortic valve Effective regurgitant orifice area by US.doppler+Calculated by PISA method 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 Effective regurgitant orifice area. It is commonly used with the system or sample type Aortic valve.

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 Effective regurgitant orifice area. It is commonly used with the system or sample type Aortic valve.

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.doppler+Calculated by PISA method

What it does not mean

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

Key facts

Aortic valve Effective regurgitant orifice area by US.doppler+Calculated by PISA method

Effective regurgitant orifice area

The effective regurgitant orifice area (EROA) is the size of the defect where the valve leaflets are not aligning normally (coaptation defect). The severity of regurgitation is related to the EROA. Proximal isovelocity surface area (PISA) is a method for calculating the EROA using color flow Doppler and is based on flow dynamics and the continuity principle, which states that in the absence of a leak or additional flow into a conduit, the flow rate will be constant along the length of the conduit, whether the conduit is the heart or the regurgitant jet. The EROA is calculated from the flow and peak velocity at the regurgitant orifice, where the flow is based on the radius at the orifice and the Nyquist limit (aliasing velocity), which is the velocity at which the color flow switches from red to blue or blue to red, and the peak velocity is measured using continuous wave Doppler of the jet. [PMID17898369]

AO; AoV; AV; AVA; Calc; Calculation; CARD.US; Cardio; Cardiology; DOP; DUPLEX; Echography; ERO; EROA; Heart Disease; Point in time; Proximal Isovelocity Surface Area; QNT; Quan; Quant; Quantitative; Random; ROA; Sonogram; Sonograph; Sonography; ULS; Ultrasound

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

Aortic valve Effective regurgitant orifice area by US.doppler+Calculated by PISA methodAV EROA PISAEffective regurgitant orifice areaCARD.USAreaPtAortic valve

Frequently asked questions

Code details

Code77909-0

SystemLOINC

Display nameAortic valve Effective regurgitant orifice area by US.doppler+Calculated by PISA method

DescriptionEffective regurgitant orifice area

Short nameAV EROA PISA

ComponentEffective regurgitant orifice area

PropertyArea

TimingPt

System (specimen)Aortic valve

ScaleQn

MethodUS.doppler+Calculated by PISA method

ClassCARD.US

Example unitscm2

StatusACTIVE

Order/ObservationObservation

Flags

BillableNo

Valid clinical useNo

Source

SourceLOINC

Version2.82

Releasemain

First released2.52

Last changed2.56

Part names

Effective regurgitant orifice areaAreaPtAortic valveQnUS.doppler+Calculated by PISA methodPoint 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.