17856-6

Hemoglobin A1c/Hemoglobin.total in Blood by HPLC

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Term Description

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.
Source: Regenstrief LOINC

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

Reference Information

Fully-Specified Name

Component

Hemoglobin A1c/Hemoglobin.total

Property

MFr

Time

Pt

System

Bld

Scale

Qn

Method

HPLC

Additional Names

Short Name

HbA1c MFr Bld HPLC

Display Name

HbA1c HPLC (Bld) [Mass fraction]

Consumer Name Alpha Get Info

HbA1c/Total Hgb, Blood

Basic Attributes

Class

CHEM

Type

Laboratory

First Released

Version 1.0l

Last Updated

Version 2.73

Change Reason

Release 2.70: CLASS: Changed Class from HEM/BC to CHEM as A1C tests are more correctly classified in CHEM.;

Order vs. Observation

Both

Common Test Rank Get Info

136

Member of these Panels

Member of these Groups Get Info

Language Variants Get Info

Related Names

• Blood
• Chemistry
• Endocrine
• Endocrinology
• GHb
• Glycated hemoglobin
• Glycohaemogolobin
• Glycohemogolobin
• Glycosylated hemoglobin
• HA1c
• Haemoglobin
• Hb
• HbA1c
• Hgb
• Hgb A1c
• High performance liquid chromatography
• High pressure liquid chromatography
• Mass Fraction
• Percent
• Point in time
• QNT
• Quan
• Quant
• Quantitative
• Random
• Tot
• Totl
• UniversalLabOrders
• WB
• Whole blood

Example Units

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Copyright © 2024 Regenstrief Institute, Inc. All Rights Reserved. To the extent included herein, the LOINC table and LOINC codes are copyright © 1995-2024, Regenstrief Institute, Inc. and the Logical Observation Identifiers Names and Codes (LOINC) Committee. See https://loinc.org/license for the full LOINC copyright and license.