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 21604-4: Wheat dust IgE RAST class (S)

Name: LOINC Code 21604-4: Wheat dust IgE RAST class (S)
Creator: HealthAssure Clinical Team
Published: 2026-05-21T11:17:29.463Z

21604-4 is a LOINC code used to identify Wheat dust IgE RAST class (S) 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 Wheat dust Ab.IgE.RAST class. It is commonly used with the system or sample type Ser.

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 Wheat dust Ab.IgE.RAST class. It is commonly used with the system or sample type Ser.

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: DEPRECATED
Order vs observation: Observation

What it does not mean

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

Key facts

Deprecated Wheat dust IgE Ab RAST class [Presence] in Serum
Wheat dust Ab.IgE.RAST class
ABS; Aby; Allergen; Allergens; ALLERGY TESTING; Antby; Anti; Antibodies; Antibody; Autoantibodies; Autoantibody; IgE RAST; Immune globulin E; Immunoglobulin E; Ordinal; Point in time; PR; QL; Qual; Qualitative; Random; Screen; Serum; SR

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

Wheat dust IgE RAST class (S)Deprecated Wheat dust IgE Ab RAST class [Presence] in SerumDeprecated Wheat Dust IgE RAST QlWheat dust Ab.IgE.RAST classALLERGYWheat dust allergy testPrThr

Frequently asked questions

Code details

Code21604-4

SystemLOINC

Display nameWheat dust IgE RAST class (S)

DescriptionWheat dust Ab.IgE.RAST class

Short nameDeprecated Wheat Dust IgE RAST Ql

ComponentWheat dust Ab.IgE.RAST class

PropertyPrThr

TimingPt

System (specimen)Ser

ScaleOrd

ClassALLERGY

StatusDEPRECATED

Order/ObservationObservation

Flags

BillableNo

Valid clinical useNo

Source

SourceLOINC

Version2.82

Releasemain

First released1.0m

Last changed2.75

Consumer names

Wheat dust allergy test

Part names

Wheat dust Ab.IgE.RAST classPrThrPtSerOrdPresence or ThresholdPoint in time (spot)Serum

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.