Talk:Glycosylated hemoglobin

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[edit] Merge

Merge. Let's keep Glycosylated hemoglobin and have HbA1C as a redirect. -- Boris 19:48, 10 February 2006 (UTC)

[edit] Defining our terms

There seems to be a great deal of confusion surrounding the following terms, among others:

hemoglobin A1c
glycosylated hemoglobin
glycohemoglobin
glycated hemoglobin

Apparently, many of these are synonymous with hemoglobin A1c. However, there is a term that refers collectively to hemoglobin A1a, hemoglobin A1b, and hemoglobin A1c. (My money is on glycohemoglobin.) This quantity (HbA1a+HbA1b+HbA1c) is expressed as a percentage, as is hemoglobin A1c. For example, your HbA1c level might be 11.7%, while your HbA1a+HbA1b+HbA1c level is 15.7% -- but what do you call your HbA1a+HbA1b+HbA1c level?

I hope that we can get this sorted out, but I will really need help rearching the topic. The following resources are quite interesting but contradictory:

http://www.webmd.com/content/article/46/1667_50935.htm
http://www.webmd.com/hw/diabetes_1_2/hw8432.asp

One states that glycohemoglobin measures only HbA1c, while the other states that it measures HbA1a+HbA1b+HbA1c.

The Wikipedia article on glycation refers to glycated hemoglobin, giving a description that is essentially the same as that given here for glycosylated hemoglobin. Meanwhile, according to the article at http://www.webmd.com/content/article/46/1667_50935.htm, the term "glycosylated hemoglobin" is incorrect, and "glycated hemoglobin" should be used instead. If we are to believe these resources, then the name of this article should be changed from "glycosylated hemoglobin" to "glycated hemoglobin."

Regardless of how all of this is sorted out, coordinated changes may be needed on the following Wikipedia articles:

glycohemoglobin
glycation
A1c

Mark D Hardy 17:50, 5 December 2006 (UTC)

The Medical Subject Headings of the US National Library of Medice have "Hemoglobin A, Glycosylated" as standard entry.  Andreas  (T) 20:22, 20 December 2006 (UTC)

Yuk, no to "Hemoglobin A, Glycosylated", we don't have Lincoln, Abraham as an article so why try a libraian classification form of naming. A search of the WHO website (http://www.who.org) for HbA1 or OGTT seems to come up with consistant articles using "glycated hemoglobin" ("glycosylated hemoglobin" seems less widely used). I wonder though, is there a difference in usage of terms between countries ? David Ruben Talk 02:58, 21 December 2006 (UTC)

Perhaps the most official authority is the IUPAC-IUB Joint Commission on Biochemical Nomenclature (JCBN). In their 1985 recommendations on nomenclature of glycoproteins, glycopeptides and peptidoglycans, the following is stated:

The terms 'protein glucosylation (or glycosylation)' and 'glucosylated (or glycosylated) hemoglobin' have been used improperly to refer to the products of non-enzymic reactions between glucose or other sugars and free amino groups of proteins. Compounds formed in this manner are not glycosides, however, as they result from the formation of a Schiff base followed by Amadori rearrangement to 1-deoxyketos-1-yl derivatives of the proteins. For example, the product of the reaction between glucose and hemoglobin is not glucosylated hemoglobin but N-(1-deoxyfructos-1-yl)hemoglobin. The term 'glycation' is suggested for all such reactions that link a sugar to a protein or peptide. The product of glycation is a glycoprotein, or, in the special case of the reaction with hemoglobin, glycohemoglobin. When appropriate, a more precise name such as (1-deoxyfructos-1-yl)hemoglobin may be used.

It seems that in fact, NIH disregards the official guidelines.

We have also to take into account that according to WP guidelines, the most common term is to be used as a title.

Google test:

  • "glycated hemoglobin" 155,000
  • "glycosylated hemoglobin" 118,000
  • "glycated haemoglobin" 102,000
  • "glycosylated haemoglobin" 101,000
  • "glycohemoglobin" 98.700
  • "glycohaemoglobin" 10,400

 Andreas  (T) 14:59, 21 December 2006 (UTC)

Thanks for researching. I see your point about using the most common term for the title as per Wikipedia guidelines. It does seem that the most common correct term should be used, and the above implies that glycosylated hemoglobin is not a correct term. An encyclopedia really ought to dispel common misperceptions rather than perpetuate them! Let's be bold and set the record straight.

As of this writing, I believe the following to be true, but again, it's all very hard to research, given the amount of misinformation out there:

- Hemoglobin A1c is one form of glycated hemoglobin, but it is not the only form.
- The term glycated hemoglobin refers collectively to hemoglobin A1a, hemoglobin A1b, and hemoglobin A1c. Of these, hemoglobin A1c is of the greatest interest -- hence the tendency to incorrectly use the terms hemoglobin A1c and glycated hemoglobin interchangeably.
- The terms glycated hemoglobin and glycohemoglobin are synonymous.
- The term glycosylated hemoglobin does not apply in this context, although it is frequently used erroneously in place of glycated hemoglobin.

I look forward seing the above assertions either shot down and/or supported with more research. Mark D Hardy 19:07, 28 December 2006 (UTC)


Following on from Andreas research re frequency terms found by googling, I've done the same searches with PubMed, the results are as tabulated below (I've tweaked the sequence so that American & British spellings lie adjacent). i also tried searching for the abbreviations HbA1 and HbA1c
Term Google test PubMed
glycated hemoglobin 155,000 987
glycated haemoglobin 102,000 774
glycosylated hemoglobin 118,000 2,900
glycosylated haemoglobin 101,000 1,242
glycohemoglobin 98.700 500
glycohaemoglobin 10,400 76
HbA1 - 12,259
HbA1c - 14,512

The clear majority of biomnedical papers use "glycosylated h(a)emoglobin", but even more use an abbreviation. My twopence is therefore to stick with "glycosylated h(a)emoglobin", and the current selection is the American spelling. David Ruben Talk 20:45, 28 December 2006 (UTC)

Please note that HbA1c is an abbreviation for hemoglobin A1c, but I'm claiming that the term 'hemoglobin A1c' is not interchangeable with the terms 'glycated hemoglobin', 'glycohemoglobin', or 'glycosylated hemoglobin' -- I'm claiming that hemoglobin A1c is one form of glycated hemoglobin, but not the only form. Apparently, at one time there were separate articles on hemoglobin A1c and glyc...hemoglobin, but then they were merged. I'm saying (among other things) that the difference between these terms is not being made clear. Not sure whether separate articles would be needed. Mark D Hardy 22:40, 28 December 2006 (UTC)

I redirected glycohemoglobin to this page - it was a stub with no references and was possibly misleading per the above discussion. For my 2 cents, Hb A1C is the only form of glycosylated hemoglobin in routine clinical use - I don't see the need for separate pages as long as the definitions are clear on the single page which discusses them both. -RustavoTalk/Contribs 22:42, 20 April 2007 (UTC)

[edit] Interpretation of HbA1c Results

The table for conversion of HbA1c result to Average Blood Sugar in mg/dL,shows that for HbA1c of 6 & 7 the Average Blood Sugar is 120 mg/dL and 150 mg/dL respectively. However, the refernce [1] cited in the article has the coversion as 135 mg/dL& 170 mg/dL for Average Blood Sugar. Which one is accurate? --Ugaap 15:38, 13 February 2007 (UTC)

[edit] Etymology?

Sorry if I missed it, but I couldn't find the derivation of the term "A1c" in the article or here. Anyone know it? David 15:32, 22 October 2007 (UTC)

The name A1c is historic. When purifying hemoglobin A (consisting of two alpha and two beta subunits), one of the minor subfractions found was called A1. This was further separated by Huising et al. into three subfractions, called A1a, A1b, and A1c. At the time, nobody had any idea what these different fractions were chemically, so the naming is arbitrary and can only be understood from the history of discovery. It appears difficult to incorporate this information into the article.  Andreas  (T) 01:53, 23 October 2007 (UTC)

[edit] NDEP says the preferred term is "A1C"

I appreciate the discussion about the various terms. This appears to have been a problem for others as well. Here is a memo from The National Diabetes Education Program [1]:

—

TO: All NDEP Partner Organizations

DATE: September 7, 2001

FROM: NDEP Executive Committee

RE: NDEP Adoption of A1C – a Simple Name for Hemoglobin A1c

The National Diabetes Education Program (NDEP) Steering Committee has agreed to adopt a simple name for the hemoglobin A1c test that is used to monitor long-term blood glucose control. The new name “A1C” will be used in all NDEP communications with people with diabetes. NDEP’s market research with consumers and health care providers indicated a need for a simple name for the test and that A1C was the most acceptable choice. As a result:

• All NDEP partners are urged to use the simple name A1C in all communications with people with diabetes that mention the test.

• All NDEP partners are urged to inform their constituents/members that NDEP is promoting use of the simple name A1C with people with diabetes and to ask for their support of the name’s use.

—

Note that it uses upper case "A" and "C." I have been using this term in my scientific and medical writing with no pushback from editors or reviewers for several years now. It seems like we ought to address this name explicitly. Ben 23:53, 26 October 2007 (UTC)

Interesting if that is how officially will be known in US, but in UK (and I suspect elsewhere in world) HbA1c will continue to be used.(eg from National Institute for Clinical Excellence Management of type 2 diabetes - Managing blood glucose levels (Guideline G) (PDF) see section 3.1) Also, the term is useful because it is quite apparent what is being tested (ie glycosylated haemaglobin, and as red blood cells survive for about 120 days, so HbA1c test gives meaning information over glucose levels in the last 6weeks).David Ruben Talk 03:44, 27 October 2007 (UTC)
Assuming I've not entirely used an incorrect search expression, but PubMed for 'A1C NOT("HbA1c") NOT("hemoglobin A1c") NOT("haemoglobin A1c")' gives 679 hits, so does not seem scintific literature yet favours this vs alternatives tabulated above. David Ruben Talk 03:52, 27 October 2007 (UTC)