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 76638-6: R-R interval (Maximum value during study) by EKG

Name: LOINC Code 76638-6: R-R interval (Maximum value during study) by EKG
Creator: HealthAssure Clinical Team
Published: 2026-05-21T08:59:57.646Z

76638-6 is a LOINC code used to identify R-R interval (Maximum value during study) by EKG 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 RR interval. It is commonly used with the system or sample type Heart.

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 RR interval. It is commonly used with the system or sample type Heart.

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: EKG

What it does not mean

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

Key facts

R-R interval (Maximum value during study) by EKG
RR interval
Cardiac; Cardio; Cardiology; ECG; EKG.MEASUREMENTS; Electrocardiogram; Electrocardiograph; Heart Disease; Hrt; Maximum; QNT; Quan; Quant; Quantitative; R-R interval; Studies; Study; Sutdies

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

R-R interval (Maximum value during study) by EKGR-R interval Max EKGRR intervalEKG.MEASTimeStdy^maxHeart

Frequently asked questions

Code details

Code76638-6

SystemLOINC

Display nameR-R interval (Maximum value during study) by EKG

DescriptionRR interval

Short nameR-R interval Max EKG

ComponentRR interval

PropertyTime

TimingStdy^max

System (specimen)Heart

ScaleQn

MethodEKG

ClassEKG.MEAS

Example unitss

StatusACTIVE

Order/ObservationObservation

Flags

BillableNo

Valid clinical useNo

Source

SourceLOINC

Version2.82

Releasemain

First released2.52

Last changed2.54

Part names

RR intervalTimeStdy^maxHeartQnEKGR-R intervalTime (e.g. seconds)Electrocardiogram (EKG)

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.