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.

LOINCActiveObservation

LOINC Code 2031-3: Carboxyhemoglobin (BldC) [Mass fraction]

Name: LOINC Code 2031-3: Carboxyhemoglobin (BldC) [Mass fraction]
Creator: HealthAssure Clinical Team
Published: 2026-05-25T17:13:11.347Z

2031-3 is a LOINC code used to identify Carboxyhemoglobin (BldC) [Mass fraction] 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 Carboxyhemoglobin/Hemoglobin.total. It is commonly used with the system or sample type BldC.

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 Carboxyhemoglobin/Hemoglobin.total. It is commonly used with the system or sample type BldC.

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: Observation

What it does not mean

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

Key facts

Carboxyhemoglobin/Hemoglobin.total in Capillary blood
Carboxyhemoglobin/Hemoglobin.total
Blood - capillary; Cap bld; Cap blood; Capillary bld; Capillary blood; Carbon monoxide.hemoglobin; Carbonmonoxyhemoglobin; Carbonyl haemoglobin; Carbonyl hemoglobin; Carbonyl Hgb; Carboxyhaemoglobin; Carboxyhemoglob; Chemistry; CO haemoglobin; CO hemoglobin; COHb; COHgb; Finger stick; Haemoglobin; Hb; HbCO; Hemoglobin bound with carbon dioxide; Hgb; Lung; Mass Fraction; Percent; Point in time; Pulmonary; Pulmonology; QNT; Quan; Quant; Quantitative; Random; Respiratory; Tot; Totl

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 Carboxyhemoglobin (BldC) [Mass fraction] (2031-3)

Related observations and tests

SNOMED_CT 705114005high

LOINC Code System

Source: LOINC-SNOMED cooperation package

Common synonyms

Carboxyhemoglobin (BldC) [Mass fraction]Carboxyhemoglobin/Hemoglobin.total in Capillary bloodCOHgb MFr BldCCarboxyhemoglobin/Hemoglobin.totalCHEMCarboxyhemoglobin/Total Hgb, BloodMFr

Frequently asked questions

Code details

Code2031-3

SystemLOINC

Display nameCarboxyhemoglobin (BldC) [Mass fraction]

DescriptionCarboxyhemoglobin/Hemoglobin.total

Short nameCOHgb MFr BldC

ComponentCarboxyhemoglobin/Hemoglobin.total

PropertyMFr

TimingPt

System (specimen)BldC

ScaleQn

ClassCHEM

Example units%

StatusACTIVE

Order/ObservationObservation

Flags

BillableNo

Valid clinical useNo

Source

SourceLOINC

Version2.82

Releasemain

First released1.0

Last changed2.73

Consumer names

Carboxyhemoglobin/Total Hgb, Blood

Part names

Carboxyhemoglobin/Hemoglobin.totalMFrPtBldCQnMass fractionPoint in time (spot)Blood capillary

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.