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.

LOINCObservation

LOINC Code 25991-1: TSH pre dose TRH IN [Moles/Vol]

Name: LOINC Code 25991-1: TSH pre dose TRH IN [Moles/Vol]
Creator: HealthAssure Clinical Team
Published: 2026-05-21T08:59:13.650Z

25991-1 is a LOINC code used to identify TSH pre dose TRH IN [Moles/Vol] 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 Thyrotropin^pre dose TRH IN. It is commonly used with the system or sample type Ser/Plas.

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 Thyrotropin^pre dose TRH IN. It is commonly used with the system or sample type Ser/Plas.

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: DISCOURAGED
Order vs observation: Observation

What it does not mean

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

Key facts

Thyrotropin [Moles/volume] in Serum or Plasma --pre dose TRH IN
Thyrotropin^pre dose TRH IN
Before; CHEMISTRY.CHALLENGE TESTING; Endocrine; Endocrinology; Level; Pl; Plasma; Plsm; Point in time; pre TRH; pre TRH IN; QNT; Quan; Quant; Quantitative; Random; SerP; SerPl; SerPlas; Serum; Serum or plasma; SR; Substance concentration; Thyroid stimulating hormone; Thyrotropic hormone; Thyrotropin-Releasing Hormone Intranasal; TSH

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

TSH pre dose TRH IN [Moles/Vol]Thyrotropin [Moles/volume] in Serum or Plasma --pre dose TRH INTSH pre TRH IN SerPl-sCncThyrotropin^pre dose TRH INCHALThyroid Stimulating Hormone (TSH; Thyrotropin) before dose TRH IN, BloodSCnc

Frequently asked questions

Code details

Code25991-1

SystemLOINC

Display nameTSH pre dose TRH IN [Moles/Vol]

DescriptionThyrotropin^pre dose TRH IN

Short nameTSH pre TRH IN SerPl-sCnc

ComponentThyrotropin^pre dose TRH IN

PropertySCnc

TimingPt

System (specimen)Ser/Plas

ScaleQn

ClassCHAL

StatusDISCOURAGED

Order/ObservationObservation

Flags

BillableNo

Valid clinical useNo

Source

SourceLOINC

Version2.82

Releasemain

First released2.00

Last changed2.42

Consumer names

Thyroid Stimulating Hormone (TSH; Thyrotropin) before dose TRH IN, Blood

Part names

Thyrotropin^pre dose TRH INSCncPtSer/PlasQnSubstance ConcentrationPoint in time (spot)Serum or Plasma

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.