LOINCActiveObservation

LOINC Code 81271-9: Trimester at onset of illness

81271-9 is a LOINC code used to identify Trimester at onset of illness 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 Trimester at onset of illness. 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 Trimester at onset of illness. 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

  • Trimester at onset of illness
  • H+P; H+P.HX; Ordinal; P prime; Point in time; QL; Qual; Qualitative; Random; Screen

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

Trimester at onset of illnessH&P.HXTimePt^PatientOrdTime (e.g. seconds)

Frequently asked questions

Code details

Code81271-9
SystemLOINC
Display nameTrimester at onset of illness
Short nameTrimester at onset of illness
ComponentTrimester at onset of illness
PropertyTime
TimingPt
System (specimen)^Patient
ScaleOrd
ClassH&P.HX
StatusACTIVE
Order/ObservationObservation

Flags

BillableNo
Valid clinical useNo

Source

SourceLOINC
Version2.82
Releasemain
First released2.56
Last changed2.56

Part names

Trimester at onset of illnessTimePt^PatientOrdTime (e.g. seconds)Point 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.

LOINC Code 81271-9 | HealthAssure