LOINCActiveObservation

LOINC Code 90558-8: Central hypopnea [#]

90558-8 is a LOINC code used to identify Central hypopnea [#] 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 Central hypopnea. It is commonly used with the system or sample type ^Patient.

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 Central hypopnea. It is commonly used with the system or sample type ^Patient.

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

What it does not mean

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

Key facts

  • Central hypopnea [#]
  • Central hypopnea
  • The sum of all central hypopneas identified during the sleep time of the polysomnography (PSG) study.
  • Cnt; Count; Lung; Neuro; Neurology; Number; PULMONARY; Pulmonology; QNT; Quan; Quant; Quantitative; Respiratory; 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

Central hypopnea [#]Num central hypopneaCentral hypopneaPULMNumStdy^Patient

Frequently asked questions

Code details

Code90558-8
SystemLOINC
Display nameCentral hypopnea [#]
DescriptionCentral hypopnea
Short nameNum central hypopnea
ComponentCentral hypopnea
PropertyNum
TimingStdy
System (specimen)^Patient
ScaleQn
ClassPULM
Example units#
StatusACTIVE
Order/ObservationObservation

Flags

BillableNo
Valid clinical useNo

Source

SourceLOINC
Version2.82
Releasemain
First released2.65
Last changed2.65

Part names

Central hypopneaNumStdy^PatientQnNumber (count)Study

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 90558-8 | HealthAssure