LOINCActiveBoth

LOINC Code 75931-6: Inspiration/Expiration time Ratio

75931-6 is a LOINC code used to identify Inspiration/Expiration time Ratio 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 Inspiration/Expiration. It is commonly used with the system or sample type Respiratory system.

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 Inspiration/Expiration. It is commonly used with the system or sample type Respiratory system.

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: Both

What it does not mean

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

Key facts

Inspiration/Expiration time Ratio
Inspiration/Expiration
Inspiration/expiration time ratio is the ratio of the length of time for inspiration to the length of time for expiration in a single respiratory cycle (inspiration plus expiration). A normal inspiration/expiration time ratio is 12 to 1:3, meaning that the expiratory phase is 2 to 3 times longer than the inspiratory phase.
Breathing; Exp; In; Insp; Inspiratory; Lung; Lungs; Point in time; PULMONARY; Pulmonology; QNT; Quan; Quant; Quantitative; Random; Respiratory; RS; Time ratio

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

Inspiration/Expiration time RatioInsp/Exp time RatioInspiration/ExpirationPULMTRtoPtRespiratory system

Frequently asked questions

Code details

Code75931-6
SystemLOINC
Display nameInspiration/Expiration time Ratio
DescriptionInspiration/Expiration
Short nameInsp/Exp time Ratio
ComponentInspiration/Expiration
PropertyTRto
TimingPt
System (specimen)Respiratory system
ScaleQn
ClassPULM
Example unitsratio
StatusACTIVE
Order/ObservationBoth

Flags

BillableNo
Valid clinical useNo

Source

SourceLOINC
Version2.82
Releasemain
First released2.54
Last changed2.54

Part names

Inspiration/ExpirationTRtoPtRespiratory systemQnTime RatioPoint in time (spot)

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.