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Harold

Harmonizing Glycated Hemoglobin Testing or HbA1c New Method

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Harold

This came up in another thread causing some confusion. Apparently some labs around the world have started reporting HbA1c's according to a new standard determined by The International Federation of Clinical Chemistry Working Group (IFCC-WG). The DCCT/UKPDS range and numbers that we are all use to using run higher than the IFCC range and numbers. Placed a LINK, titled NGSP, to a PDF file on the NGSP site in the Resource Directory under Diabetes explaining the relationship. There is a formula and a chart for converting along with a graph for a quick view.

 

IMHO we will need to state which standard our A1c is given in our post and signatures. Example; 7.0/DCCT for the older standard or the equivalent 5.4/IFCC

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morrisma

It wasn't enough we need to multiply or divide by 18 to compare BGs. Now we have to first, find out what A1c standard we are measured against and then convert to compare those too.

 

Another case of Entropy. Things really should get simpler not more complex....

Mike

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TomB

Harold,

This reminds me of "Who's on 1st, What's on 2nd and I don't know's on 3rd." I might have to do more checking on A!C variations. I had a blood test in June, 2002 that came back with "A1C = 6.1% corresponding to a mean of 117 mg/dl." I converted that 6.1% to 141 mg/dl and used that as part of a claim I submitted to the VA to establish a diagnotic date for DMII. I'm aware that A1c shouldn't be used to make a diagnosis but I'm trying my best to do that anyway. Your thoughts?

Tom

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Harold

Typically it takes 2 test a month or so so apart to get a DM diagnosis. It use to be a fasting reading over 140, an A1c at or over 7%, and/or failing a GTT a month after one of the other two would do it. Now the 140 has been reevaluated down to 126 and a fasting over 100 but less than 126 will get you a Pre DM diagnosis. That was or is typical, the exceptions being a fasting reading over 200 or an A1c over 8 will get you a congratulations you have Diabetes! :eek:

 

As far as I know, and my labs came back this week with an A1c of 6%, labs in the US are still giving the A1c/DCCT out using the old calibration method for their equipment.

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MikeJsimon

Lets be clear this is only a consideration for the diagnosis of Type 2 diabetes. I am in agreement with the more cautious approach of Dr Bloomgarden — are we saying that it needs 2 separate measurements x weeks apart as with FBG or OGT? (dangerous if it is Type 1!) Do we know what happens to HbA1c values in children who often have transient high blood glucose values after stress such as convulsion or treatment for Asthma with Salbutamol and /or steroids? I would still stay with the overall assessment of the child rather than attach a diagnosis on the basis of an HbA1c.

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ShottleBop

The new ABA recommendation to diagnose T2 based on an A1c of 6.5 requires only a single reading. The A1c is, very roughly, a three-month rolling average of your BGs; requiring two readings long enough apart might delay treatment unnecessarily. (IIRC, the A1c is in addition to, and does not replace, the FBG and OGTT as alternative bases for diagnosis.)

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JJM335
IMHO we will need to state which standard our A1c is given in our post and signatures. Example; 7.0/DCCT for the older standard or the equivalent 5.4/IFCC

 

My understanding is the the new system, which will quote A1c in mmol/mol will give very different numbers, so that 7.0% in the old system will be equivalent to 53 (not 5.4) in the new one.

 

Change in HbA1c level reporting from June

 

I agree it is a PITA to have two different systems on the go, but at least the numbers should be VERY different so there shouldn't be too much opportunity for confusion.

 

Joel

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Moonpie

oh that is plain crazy. ( different measurements ) going for my A1C tomorrow, expect it in old style.

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Renaldo09

IFCC results are accuracy-based; NGSP results can be directly related to clinical outcomes and diabetes care goals. Although the IFCC/NGSP correlation is excellent, the absolute numbers are different and there has been much debate over which numbers should be reported worldwide. The relationship between the IFCC and NGSP (both in %HbA1c) is shown in Figure 1. IFCC results are consistently 1.5-2% HbA1c lower throughout the range of values.

 

____________________

Renaldo09

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Maggiegong

I'm an Australian diagnosed in January. I'm struggling already with understanding the different numbers in North America and here but I always thought our A1c readings were alike for comparison. Now I have no idea which system I'm under and if it is indeed the same.

Maggie.

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chalup

I'm an Australian diagnosed in January. I'm struggling already with understanding the different numbers in North America and here but I always thought our A1c readings were alike for comparison. Now I have no idea which system I'm under and if it is indeed the same.
Maggie.

The Canadian system is the same as Australia and most of the rest of the world. It is only the US and maybe a couple others that use their own system. Most of the world seems to be moving to the new A1c measurements. It can be extremely confusing.

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