LOINCActiveObservation

LOINC Code 18505-8: R-R interval (Mean value during study) by EKG

18505-8 is a LOINC code used to identify R-R interval (Mean 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 (Mean value during study) by EKG
  • RR interval
  • Added to accommodate measures defined in CEN/TC251/PT007, SCP-ECG (Standard Communications Protocol for Computerized Electrocardiography)
  • Average; Avg; Cardiac; Cardio; Cardiology; ECG; EKG.MEASUREMENTS; Electrocardiogram; Electrocardiograph; Heart Disease; Hrt; 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 (Mean value during study) by EKGR-R interval MeanRR intervalEKG.MEASTimeStdy^meanHeart

Frequently asked questions

Code details

Code18505-8
SystemLOINC
Display nameR-R interval (Mean value during study) by EKG
DescriptionRR interval
Short nameR-R interval Mean
ComponentRR interval
PropertyTime
TimingStdy^mean
System (specimen)Heart
ScaleQn
MethodEKG
ClassEKG.MEAS
Example unitss
StatusACTIVE
Order/ObservationObservation

Flags

BillableNo
Valid clinical useNo

Source

SourceLOINC
Version2.82
Releasemain
First released1.0l
Last changed2.54

Part names

RR intervalTimeStdy^meanHeartQnEKGR-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.

LOINC Code 18505-8 | HealthAssure