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.

LOINCActiveBoth

LOINC Code 6543-3: R. rickettsii Ag IF Nom (Tiss)

Name: LOINC Code 6543-3: R. rickettsii Ag IF Nom (Tiss)
Creator: HealthAssure Clinical Team
Published: 2026-05-25T17:13:11.347Z

6543-3 is a LOINC code used to identify R. rickettsii Ag IF Nom (Tiss) 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 Rickettsia rickettsii Ag. It is commonly used with the system or sample type Tiss.

Reviewed by HealthAssure Clinical TeamUpdated 25 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 Rickettsia rickettsii Ag. It is commonly used with the system or sample type Tiss.

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
Method: IF

What it does not mean

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

Key facts

Rickettsia rickettsii Ag [Identifier] in Tissue by Immunofluorescence
Rickettsia rickettsii Ag
ACIF; Anticomplement Immunofluorescence; Antigen; Antigens; DFA; FA; Fluorescent antibody; Fluoresent; ID; Identity or presence; IFA; Immune fluorescence; Immunoflour; Immunofluor; Immunofluorescence; Infectious Disease; InfectiousDisease; Microbiology; Nominal; Point in time; R rickettsi; R rickettsii; Random; Ricket; Rickettsial; RMSF; Rocky mountain spotted fever; Spotted fever; Time Resolved Fluorescence; Tissue; Tissue, unspecified; TRF

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.

Related SNOMED CT concepts

705114005SNOMED CT mapping for R. rickettsii Ag IF Nom (Tiss) (6543-3)

Related observations and tests

SNOMED_CT 705114005high

LOINC Code System

Source: LOINC-SNOMED cooperation package

Common synonyms

R. rickettsii Ag IF Nom (Tiss)Rickettsia rickettsii Ag [Identifier] in Tissue by ImmunofluorescenceR rickettsi Ag Tiss IFRickettsia rickettsii AgMICRORickettsia rickettsii antigen, TissuePrid

Frequently asked questions

Code details

Code6543-3

SystemLOINC

Display nameR. rickettsii Ag IF Nom (Tiss)

DescriptionRickettsia rickettsii Ag

Short nameR rickettsi Ag Tiss IF

ComponentRickettsia rickettsii Ag

PropertyPrid

TimingPt

System (specimen)Tiss

ScaleNom

MethodIF

ClassMICRO

StatusACTIVE

Order/ObservationBoth

Flags

BillableNo

Valid clinical useNo

Source

SourceLOINC

Version2.82

Releasemain

First released1.0g

Last changed2.22

Consumer names

Rickettsia rickettsii antigen, Tissue

Part names

Rickettsia rickettsii AgPridPtTissNomIFPresence or IdentityPoint in time (spot)Tissue and SmearsImmunofluorescence (IF)

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.