LOINCActiveBoth

LOINC Code 81691-8: MLH-1 Ag Immune stain Ql (Cancer specimen)

81691-8 is a LOINC code used to identify MLH-1 Ag Immune stain Ql (Cancer specimen) 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 MLH-1 Ag. It is commonly used with the system or sample type Cancer specimen.

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 MLH-1 Ag. It is commonly used with the system or sample type Cancer specimen.

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: Immune stain

What it does not mean

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

Key facts

  • MLH-1 Ag [Presence] in Cancer specimen by Immune stain
  • MLH-1 Ag
  • Antigen; Antigens; CA; Ca spec; i; IHC; Imm; Immunohistochemical stain; Immunostain; ImStn; Imun; Imune; Ordinal; PATHOLOGY; Point in time; PR; QL; Qual; Qualitative; Random; Screen; Spec; St; Stains; Stn

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

MLH-1 Ag Immune stain Ql (Cancer specimen)MLH-1 Ag [Presence] in Cancer specimen by Immune stainMLH-1 Ag Ca spec Ql ImStnMLH-1 AgPATHMLH-1 antigen, Cancer specimenPrThr

Frequently asked questions

Code details

Code81691-8
SystemLOINC
Display nameMLH-1 Ag Immune stain Ql (Cancer specimen)
DescriptionMLH-1 Ag
Short nameMLH-1 Ag Ca spec Ql ImStn
ComponentMLH-1 Ag
PropertyPrThr
TimingPt
System (specimen)Cancer specimen
ScaleOrd
MethodImmune stain
ClassPATH
StatusACTIVE
Order/ObservationBoth

Flags

BillableNo
Valid clinical useNo

Source

SourceLOINC
Version2.82
Releasemain
First released2.56
Last changed2.82

Consumer names

MLH-1 antigen, Cancer specimen

Part names

MLH-1 AgPrThrPtCancer specimenOrdImmune stainPresence or ThresholdPoint in time (spot)

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.

LOINC Code 81691-8 | HealthAssure