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 53683-9: Fetal Head.fourth cerebral ventricle Diameter.anterior-posterior US

Name: LOINC Code 53683-9: Fetal Head.fourth cerebral ventricle Diameter.anterior-posterior US
Creator: HealthAssure Clinical Team
Published: 2026-05-21T08:59:36.581Z

53683-9 is a LOINC code used to identify Fetal Head.fourth cerebral ventricle Diameter.anterior-posterior US 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.anterior-posterior. It is commonly used with the system or sample type Head.fourth cerebral ventricle^Fetus.

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.anterior-posterior. It is commonly used with the system or sample type Head.fourth cerebral ventricle^Fetus.

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.measured

What it does not mean

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

Key facts

Fetal Head.fourth cerebral ventricle Diameter.anterior-posterior US
Diameter.anterior-posterior
4th; APAD; Brain; Cereb; Cranial; Cranium; DIA; Diam; Diam AP; Echoencephalogram; Echoencephalography; Echography; Fetal; Gyn; Gynecology; Head 4th CV; Intracranial; Length; OB; ObGyn; OBSTERICAL; OBSTERICAL.ULTRASOUND; Obstetrical; Obstetrics; Point in time; QNT; Quan; Quant; Quantitative; Random; Skull; Sonogram; Sonograph; Sonography; ULS; Ultrasound; US+Meas

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

Fetal Head.fourth cerebral ventricle Diameter.anterior-posterior USFet Head 4th CV Diam AP US.measDiameter.anterior-posteriorOB.USLenPtHead.fourth cerebral ventricle^fetus

Frequently asked questions

Code details

Code53683-9

SystemLOINC

Display nameFetal Head.fourth cerebral ventricle Diameter.anterior-posterior US

DescriptionDiameter.anterior-posterior

Short nameFet Head 4th CV Diam AP US.meas

ComponentDiameter.anterior-posterior

PropertyLen

TimingPt

System (specimen)Head.fourth cerebral ventricle^Fetus

ScaleQn

MethodUS.measured

ClassOB.US

Example unitsmm

StatusACTIVE

Order/ObservationObservation

Flags

BillableNo

Valid clinical useNo

Source

SourceLOINC

Version2.82

Releasemain

First released2.26

Last changed2.48

Part names

Diameter.anterior-posteriorLenPtHead.fourth cerebral ventricle^fetusQnUS.measuredLengthPoint in time (spot)Ultrasound.measured

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.