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 31768-5: C. trachomatis Ag Ql (Bld)

Name: LOINC Code 31768-5: C. trachomatis Ag Ql (Bld)
Creator: HealthAssure Clinical Team
Published: 2026-05-25T17:13:11.347Z

31768-5 is a LOINC code used to identify C. trachomatis Ag Ql (Bld) 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 Chlamydia trachomatis Ag. It is commonly used with the system or sample type Bld.

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 Chlamydia trachomatis Ag. It is commonly used with the system or sample type Bld.

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

What it does not mean

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

Key facts

Chlamydia trachomatis Ag [Presence] in Blood
Chlamydia trachomatis Ag
Antigen; Antigens; Blood; C trac; C trach; C tracho; C trachomatis; Chlam; Chlam trac; Chlamid; CT; ID; Infectious Disease; InfectiousDisease; LGV; Lymphogranuloma venereum; Microbiology; Ordinal; Point in time; PR; QL; Qual; Qualitative; Random; Screen; Trachoma; WB; Whole blood

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 C. trachomatis Ag Ql (Bld) (31768-5)

Related observations and tests

SNOMED_CT 705114005high

LOINC Code System

Source: LOINC-SNOMED cooperation package

Common synonyms

C. trachomatis Ag Ql (Bld)Chlamydia trachomatis Ag [Presence] in BloodC trach Ag Bld QlChlamydia trachomatis AgMICROChlamydia trachomatis antigen, BloodPrThr

Frequently asked questions

Code details

Code31768-5

SystemLOINC

Display nameC. trachomatis Ag Ql (Bld)

DescriptionChlamydia trachomatis Ag

Short nameC trach Ag Bld Ql

ComponentChlamydia trachomatis Ag

PropertyPrThr

TimingPt

System (specimen)Bld

ScaleOrd

ClassMICRO

StatusACTIVE

Order/ObservationBoth

Flags

BillableNo

Valid clinical useNo

Source

SourceLOINC

Version2.82

Releasemain

First released2.07

Last changed2.56

Consumer names

Chlamydia trachomatis antigen, Blood

Part names

Chlamydia trachomatis AgPrThrPtBldOrdPresence or ThresholdPoint in time (spot)Blood

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.