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 11820-8: Fetal Head Diameter.biparietal US

Name: LOINC Code 11820-8: Fetal Head Diameter.biparietal US
Creator: HealthAssure Clinical Team
Published: 2026-05-21T11:17:22.973Z

11820-8 is a LOINC code used to identify Fetal Head Diameter.biparietal 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.biparietal. It is commonly used with the system or sample type Head^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.biparietal. It is commonly used with the system or sample type Head^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 Diameter.biparietal US
Diameter.biparietal
Measured at level of thalamo-basal ganglia & either 3rd ventricle w/ visualization of quadrigeminal cisterns or top of 3rd ventricle w/ visualization of cavum septum pellucidi from echo leading edge to leading edge of parietal bones.
BPD; Brain; Cranial; Cranium; DIA; Diam; Echoencephalogram; Echoencephalography; Echography; Fetal; Gyn; Gynecology; 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 Diameter.biparietal USFet BPD US.measDiameter.biparietalOB.USLenPtHead^fetus

Frequently asked questions

Code details

Code11820-8

SystemLOINC

Display nameFetal Head Diameter.biparietal US

DescriptionDiameter.biparietal

Short nameFet BPD US.meas

ComponentDiameter.biparietal

PropertyLen

TimingPt

System (specimen)Head^Fetus

ScaleQn

MethodUS.measured

ClassOB.US

Example unitscm

StatusACTIVE

Order/ObservationObservation

Flags

BillableNo

Valid clinical useNo

Source

SourceLOINC

Version2.82

Releasemain

First released1.0j-a

Last changed2.73

Part names

Diameter.biparietalLenPtHead^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.