PDA

View Full Version : Things that can change HbA1c results...

Emm
03-20-2007, 05:23 AM
Have just been reading about a1c tests - did you know there are things that can change the results? Anyone know more about this - like whether it gives a lower or higher result? Or if there are other things that can stuff up the result?

What I read was:
Patients with diseases affecting hemoglobin such as anemia may get abnormal results with this test. Other abnormalities that can affect the results of the HbA1c include supplements such as Vitamin C and E and high levels of lipids. Kidney disease and liver disease may also affect the result of the HbA1c test.

on testing Your Diabetes with the Glycated Hemoglobin test or HbA1c (http://www.webmd.com/content/article/46/1667_50935.htm)

Em.
JediSkipdogg
03-20-2007, 05:38 AM
Yes that is possible. The problem with an A1C is that it is the history of BGs over a 3 month period. Alot can happen to blood cells in 3 months and some people might not even have blood cells taht can live to be 3 months old. This will then change how the A1C correlates.
LancetChick
03-20-2007, 07:28 AM
My lab does a separate test to check for hemaglobin abnormalities that can throw the A1c test off. I assumed all labs did this.
SueM
03-20-2007, 03:30 PM
an under active thyroid also screws the result of an A1c result
grace girl
03-20-2007, 04:08 PM
When my dad had his last a1c they sent him to the hopsital for the blood work and the nurse there refused to do the test because he wasn't fasting. (he wasn't having any other tests done that day, either....no other reason for the fasting) Now, I've NEVER had an a1c fasting, had never heard of it. Do any of you guys fast for it???
blacklightmike
03-20-2007, 05:21 PM
an under active thyroid also screws the result of an A1c result

Do you mean an untreated one? I ask because I'm on 300 mcg Levothyroxine.
Emm
03-20-2007, 05:24 PM
Do any of you guys fast for it???

No - not unless I'm doing some other test as well.
SueM
03-21-2007, 12:58 AM
Do you mean an untreated one? I ask because I'm on 300 mcg Levothyroxine.

If you are treated for an under active thyroid and on the right meds then you are not under active so no that wont affect the result. If taking meds and on the wrong dose then yes it will or if you are not on meds and under active (one and the same thing really)
SueM
03-21-2007, 01:05 AM
When my dad had his last a1c they sent him to the hopsital for the blood work and the nurse there refused to do the test because he wasn't fasting. (he wasn't having any other tests done that day, either....no other reason for the fasting) Now, I've NEVER had an a1c fasting, had never heard of it. Do any of you guys fast for it???

Sounds as if the nurse didn't know what she was doing.
There is no reason on earth for an established diabetic to have a fasting A1c blood sugar drawn at a lab/hospital. An A1c can be drawn at any time of the day. If you want to know your fasting blood sugar use your home meter.
In the UK the Dr ticks the form if he wants a fasting blood sugar for any other tests.
sandyhandz
03-21-2007, 06:52 AM
How does an underactive thyroid affect your A1c result - higher or lower? I'm assuming anemia would give a false lower reading?
tanyatype1
03-21-2007, 09:23 AM
When my dad had his last a1c they sent him to the hopsital for the blood work and the nurse there refused to do the test because he wasn't fasting. (he wasn't having any other tests done that day, either....no other reason for the fasting) Now, I've NEVER had an a1c fasting, had never heard of it. Do any of you guys fast for it???

I don't fast for my A1C either - although I do have to explain myself every time I go in!
nneighbour
03-21-2007, 09:26 AM
Um.. to get a true fasting HbA1c level, wouldn't you have to fast for three months?
mzizgayle
03-21-2007, 09:36 AM
I have always been told to fast, and I never questioned, along with this they also do cholesterol, triclyerides, etc. I heard that what you eat the night before can affect the triclyerides (sp) so that is why the fasting for that
tanyatype1
03-21-2007, 09:56 AM
I have always been told to fast, and I never questioned, along with this they also do cholesterol, triclyerides, etc. I heard that what you eat the night before can affect the triclyerides (sp) so that is why the fasting for that

I only have the whole work up (cholesterol ect.) once a year, but I have the A1C done every three months. I fast for the once a year thing but not when I'm just getting the blood drawn for an A1C.
suec1958
03-21-2007, 10:00 AM
Every time I get mine done, it is fasting - I go first thing in the morning, and get results from it the next week.
sofaraway
03-21-2007, 10:57 AM
I never go fasting for an A1c.

As for the anemia thing wouldn'y it give a higher result, as there is less Hb for the glucose to stick to?
type1tenorlady
03-21-2007, 11:09 AM
I have always been told to fast, and I never questioned, along with this they also do cholesterol, triclyerides, etc. I heard that what you eat the night before can affect the triclyerides (sp) so that is why the fasting for that

Yes, my dr has only told me to fast because I'm usually doing the cholesterol stuff at the same time as the A1C, but never for the A1C by itself.