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 20818-1: E. coli K99 Aggl Ql (Small intestine Tissue)

Name: LOINC Code 20818-1: E. coli K99 Aggl Ql (Small intestine Tissue)
Creator: HealthAssure Clinical Team
Published: 2026-05-25T17:13:11.347Z

20818-1 is a LOINC code used to identify E. coli K99 Aggl Ql (Small intestine Tissue) 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 Escherichia coli K99. It is commonly used with the system or sample type Tsmi.

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 Escherichia coli K99. It is commonly used with the system or sample type Tsmi.

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: Aggl

What it does not mean

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

Key facts

Escherichia coli K99 [Presence] in Small intestine Tissue by Agglutination
Escherichia coli K99
Agg; Agglut; Agglutination; E coli; E coli K99; ID; Infectious Disease; InfectiousDisease; Microbiology; o002; Ordinal; Point in time; PR; QL; Qual; Qualitative; Random; Screen; Tissue small intestine

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 E. coli K99 Aggl Ql (Small intestine Tissue) (20818-1)

Related observations and tests

SNOMED_CT 705114005high

LOINC Code System

Source: LOINC-SNOMED cooperation package

Common synonyms

E. coli K99 Aggl Ql (Small intestine Tissue)Escherichia coli K99 [Presence] in Small intestine Tissue by AgglutinationE coli K99 TSMI Ql AgglEscherichia coli K99MICROEscherichia coli K99, Small intestine tissuePrThr

Frequently asked questions

Code details

Code20818-1

SystemLOINC

Display nameE. coli K99 Aggl Ql (Small intestine Tissue)

DescriptionEscherichia coli K99

Short nameE coli K99 TSMI Ql Aggl

ComponentEscherichia coli K99

PropertyPrThr

TimingPt

System (specimen)Tsmi

ScaleOrd

MethodAggl

ClassMICRO

StatusACTIVE

Order/ObservationBoth

Flags

BillableNo

Valid clinical useNo

Source

SourceLOINC

Version2.82

Releasemain

First released1.0m

Last changed2.56

Consumer names

Escherichia coli K99, Small intestine tissue

Part names

Escherichia coli K99PrThrPtTSMIOrdAgglPresence or ThresholdPoint in time (spot)Small intestine TissueAgglutination

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.