LOINC
Version 2.70

4548-4Hemoglobin A1c/Hemoglobin.total in BloodActive

Part Description

LP16413-4   Hemoglobin A1c
Currently (2010), four standardization protocols exist for measuring Hgb A1c:

1. IFCC - designated as a Reference Method or RM (http://www.ifcchba1c.net/)
2. NGSP - the long standing protocol used in the US and most other countries since the DCCT study (http://www.ngsp.org/factors.asp)
3.JDS/JSCC - a protocol used in Japan, Spain and possibly other countries
4. Swedish - used in Sweden at least

Protocols 2-4 are known as Designated Comparison Methods (DCM) and have been connected to the Reference Method and each other through various regression equations.

Because of the high degrees of standardization within protocol it should no longer be necessary to specify a LOINC code with a method such as "HPLC", "electrophoresis" or anything else. Analytical instruments will be designed so that an Hgb A1c result can be traced back to a specific standardization protocol, so the important distinction will be the standardization protocol as described above and which will be carried in the method field.

A meeting of instrument manufacturers (presumably including Japanese) in Milan, Italy, December 12, 2007, agreed (among other items) that:

-All manufacturers should implement worldwide the traceability to the IFCC reference system for Hgb -A1c.
-All new instruments sold after January 1st, 2011 will report (as a result of an Hgb A1c test) both SI (mmol/mol – no decimals) and NGSP derived units (percentage – one decimal), in agreement with the Consensus Statement.
-Note they only committed to supporting protocol (1) and (2)

Different countries are adopting the international harmonization recommendations in different ways. We have information from the NGSP that the US will continue to report only Hgb A1c/NGSP, with the unit percent – i.e., no change. In Great Britain, labs have already started to report all results both as Hgb A1c (NGSP) in % and Hgb A1c (IFCC) in mmol/mol. In Canada, they are awaiting a recommendation from an expert panel. Any of these measures could be reported in the same units, but the convention for the reporting Hgb A1c under the new IFCC protocol will be to use units of mmol/mol to avoid confusion between the DCCT/NGSP and the IFFCC protocol.

LOINC has defined 59261-8 (Hemoglobin A1c/Hemoglobin.total in Blood) by IFCC protocol.

These protocols produce different results when expressed in the same units. For example, the equivalent of Hgb A1c (NGSP) of 6.5% is Hgb A1c (IFCC) is 4.8%.

The NGSP web site (http://www.ngsp.org/factors.asp) suggests the use of alternate measures, such as glycated albumen, for patients with severe iron deficiency, dialysis patients, and those with SS SC CC because of over or under reading that can occur with these interferences. It also describes the effect of abnormal hemoglobins on results of HbA1c by instrument.

Studies have demonstrated racial and ethnic differences in the relationship between glucose levels and hemoglobin A1C [22238408], and it has been suggested that some descendants of sub-Saharan Africa may have higher levels of measured hemoglobin A1C compared to glucose levels due to hemoglobin variants [PMID: 31675503] . Source: Regenstrief Help

Fully-Specified Name

Component
Hemoglobin A1c/Hemoglobin.total
Property
MFr
Time
Pt
System
Bld
Scale
Qn
Method

Additional Names

Short Name
HbA1c MFr Bld
Display Name
HbA1c (Bld) [Mass fraction]
Consumer Name Alpha
HbA1c/Total Hgb, Blood

Basic Attributes

Class
CHEM
Type
Laboratory
First Released
Version 1.0
Last Updated
Version 2.70
Change Reason
Release 2.70: CLASS: Changed Class from HEM/BC to CHEM as A1C tests are more correctly classified in CHEM.; Previous Releases: Changing from the property from Mass fraction to substance fraction has not effect on the meaning when the molecular weight of the numerator and the denominator are the same (for practical purposes). These terms had had a property of MFR in the past and we changed to SFR because we thought the LOINC community preferred SFR for HbA1c. But we mis understood the preference is to use the MFR variant- so we have changed back.
Order vs. Observation
Both
Common US Lab Results Rank
81
Common SI Lab Results Rank
81
Common Orders Rank
48

Reference Information

Type Source Reference
Webcontent Lab Tests Online®Copyright Copyright © 2001-2019 American Association for Clinical Chemistry Today, all US HbA1c measurements reported in the US and many other countries are standardized to the NGSP protocol and that has been true for years. This code [LOINC: 4548-4] should be used for reporting the HbA1c in the US. Other countries may report HbA1c measured by the IFCC protocol [LOINC: 59261-8], a protocol with results reported in units of mmol/mol. In Japan and parts of Spain it may be measured using the Japanese protocol. All three protocols produce different numeric values. Hemoglobin A1c
Mapping Guidance Regenstrief HelpCopyright Copyright 2001-2019 American Association for Clinical Chemistry. Today, all US HbA1c measurements reported in the US and many other countries are standardized to the NGSP protocol and that has been true for years. This code [LOINC: 4548-4] should be used for reporting the HbA1c in the US. Other countries may report HbA1c measured by the IFCC protocol [LOINC: 59261-8], a protocol with results reported in units of mmol/mol. In Japan and parts of Spain it may be measured using the Japanese protocol. All three protocols produce different numeric values. Mapper’s Guide for the Top 2000 plus LOINC Laboratory Observations

Member of these Panels

LOINC Long Common Name
52743-2 Continuity Assessment Record and Evaluation (CARE) tool - Acute Care
52748-1 Continuity Assessment Record and Evaluation (CARE) tool - Home Health Admission
52746-5 Continuity Assessment Record and Evaluation (CARE) tool - Interim
52744-0 Continuity Assessment Record and Evaluation (CARE) tool - Post Acute Care (PAC) - Admission
52745-7 Continuity Assessment Record and Evaluation (CARE) tool - Post Acute Care (PAC) - Discharge
55399-0 Diabetes tracking panel
67868-0 End Stage Renal Disease (ESRD) Medical Evidence Report, Medicare Entitlement AndOr Patient Registration - OMB CMS form 2728
54037-7 HEDIS 2009 panel
57820-3 HEDIS 2010 panel
60442-1 HEDIS 2011 panel
67767-4 HEDIS 2012 panel
72199-3 HEDIS 2013 panel
74234-6 HEDIS 2014 Value Sets
75868-0 HEDIS 2015 Value Sets
79544-3 HEDIS 2016 Value Sets
82955-6 HEDIS 2017 Value Sets
87625-0 HEDIS 2018 Value Sets
90766-7 HEDIS 2019 Value Sets
94137-7 HEDIS 2020 Value Sets
96068-2 HEDIS MY 2020 Value Sets
43150-2 Hemoglobin A1c measurement device panel

Member of these Groups

LG51070-7 Hemoglobin A1c/Hemoglobin.total|MFr|Pt|ANYBldSerPl

Language Variants Get Info

zh-CNChinese (China)
血红蛋白 A1c/血红蛋白.总计:质量分数:时间点:全血:定量型:
nl-NLDutch (Netherlands)
hemoglobine A1c/hemoglobine.totaal:massafractie:moment:bloed:kwantitatief:
et-EEEstonian (Estonia)
Hemoglobiin A1c/hemoglobiin.üld:MFr:Pt:B:Qn:
fr-BEFrench (Belgium)
Hémoglobine A1c/Hémoglobine.totale:Fraction de masse:Temps ponctuel:Sang:Quantitatif:
fr-CAFrench (Canada)
Hémoglobine A1c/Hémoglobine.totale:Fraction de masse:Temps ponctuel:Sang:Quantitatif:
fr-FRFrench (France)
Hémoglobine A1c/hémoglobine totale:Fraction massique:Ponctuel:Sang:Numérique:
de-DEGerman (Germany)
Hämoglobin A1c/Hämoglobin.total:MFr:Pkt:Blut:Qn:
it-ITItalian (Italy)
Emoglobina A1c/Emoglobina.totale:MFr:Pt:Sangue:Qn:
ko-KRKorean (Korea, Republic of)
혈색소 A1C/총혈색소:질량분획:검사시점:전혈:정량:
pt-BRPortuguese (Brazil)
Hemoglobina A1c/Hemoglobina.total:SFr:Pt:SgTotal:Qn:
ru-RURussian (Russian Federation)
Гемоглобин А1с/Гемоглобин.общий:МассДол:ТчкВрм:Кр:Колич:
es-ARSpanish (Argentina)
hemoglobina A1c/hemoglobina.total:fracción de masa:punto en el tiempo:sangre:cuantitativo:
es-ESSpanish (Spain)
Hemoglobina A1c (Hemoglobina glicosilada)/Hemoglobina.total:Fracción de masa:Punto temporal:Sangre:Qn:
tr-TRTurkish (Turkey)
Hemoglobin A1c/Hemoglobin.total:KütlFr:Zmlı:Kan:Kant:

Example Units

Unit Source
% eCHN
% Example UCUM Units
% REGENSTRIEF
% Hgb REGENSTRIEF

LOINC FHIR® API Example - CodeSystem Request Get Info

https://fhir.loinc.org/CodeSystem/$lookup?system=http://loinc.org&code=4548-4