LOINCActiveObservation

LOINC Code 11633-5: Fetal Heart rate reactivity US

11633-5 is a LOINC code used to identify Fetal Heart rate reactivity 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 Heart rate reactivity. It is commonly used with the system or sample type ^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 Heart rate reactivity. It is commonly used with the system or sample type ^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

What it does not mean

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

Key facts

Fetal Heart rate reactivity US
Heart rate reactivity
Heart rates are considered reactive ("normal") if two or more accelerations occur within a 20-minute period. Nonreactive heart rate is one in which not enough accelerations are detected in a 40-minute period and can be associated with several findings, including the fetus was asleep during the test in which case the test time may be extended. Nonreactive results can also occur if the mother is taking certain medications or that the fetus is not getting enough oxygen.[https//www.acog.org/]
Biophysical profile; Echography; Fetal; Function; Gyn; Gynecology; Heart beat; OB; ObGyn; OBSTERICAL; OBSTERICAL.ULTRASOUND; Obstetrical; Obstetrics; Ordinal; Point in time; Pulse; QL; Qual; Qualitative; Random; Screen; 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

Fetal Heart rate reactivity USFetal NST by USHeart rate reactivityOB.USFcnPt^Fetus

Frequently asked questions

Code details

Code11633-5
SystemLOINC
Display nameFetal Heart rate reactivity US
DescriptionHeart rate reactivity
Short nameFetal NST by US
ComponentHeart rate reactivity
PropertyFcn
TimingPt
System (specimen)^Fetus
ScaleOrd
MethodUS
ClassOB.US
StatusACTIVE
Order/ObservationObservation

Flags

BillableNo
Valid clinical useNo

Source

SourceLOINC
Version2.82
Releasemain
First released1.0j-a
Last changed2.71

Part names

Heart rate reactivityFcnPt^FetusOrdUSFunctionPoint in time (spot)Ultrasound

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 11633-5 | HealthAssure