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 40721-3: Hemoglobin F Apt-Downey method Ql (Specimen)

Name: LOINC Code 40721-3: Hemoglobin F Apt-Downey method Ql (Specimen)
Creator: HealthAssure Clinical Team
Published: 2026-05-21T08:59:27.146Z

40721-3 is a LOINC code used to identify Hemoglobin F Apt-Downey method Ql (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 Hemoglobin F. It is commonly used with the system or sample type XXX.

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 Hemoglobin F. It is commonly used with the system or sample type XXX.

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: Apt-Downey

What it does not mean

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

Key facts

Hemoglobin F [Presence] in Specimen by Apt-Downey method
Hemoglobin F
Fetal hemoglobin; Haemoglobin; Hb; HbF; HEMATOLOGY/CELL COUNTS; Hgb; Hgb F; Misc; Miscellaneous; Ordinal; Other; Point in time; PR; QL; Qual; Qualitative; Random; Screen; Spec; To be specified in another part of the message; Unspecified

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

Hemoglobin F Apt-Downey method Ql (Specimen)Hemoglobin F [Presence] in Specimen by Apt-Downey methodHgb F Spec Ql Apt-DowneyHemoglobin FHEM/BCHemoglobin F, SpecimenPrThr

Frequently asked questions

Code details

Code40721-3

SystemLOINC

Display nameHemoglobin F Apt-Downey method Ql (Specimen)

DescriptionHemoglobin F

Short nameHgb F Spec Ql Apt-Downey

ComponentHemoglobin F

PropertyPrThr

TimingPt

System (specimen)XXX

ScaleOrd

MethodApt-Downey

ClassHEM/BC

StatusACTIVE

Order/ObservationBoth

Flags

BillableNo

Valid clinical useNo

Source

SourceLOINC

Version2.82

Releasemain

First released2.15

Last changed2.73

Consumer names

Hemoglobin F, Specimen

Part names

Hemoglobin FPrThrPtXXXOrdApt-DowneyPresence or ThresholdPoint in time (spot)Apt-Downey method

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.