A1C vs. fasting glucose

Mistizoom · 11-28-2012, 09:10 PM

I have not been diagnosed as diabetic but I have PCOS and have been on Metformin ER 1500 mg/day for several years to control my high insulin levels. I get tested for fasting insulin and fasting blood glucose once a year. My fasting insulin is now in the normal range (though high end of normal, I think) and my fasting blood glucose has come out a 88 consistently. Last year my doc wanted to do A1C at my visit (non-fasting) but I opted to return to get the fasting glucose and insulin done. Not sure why she didn't have them do A1C then but she didn't. DH was just diagnosed with Type II (via A1C) and I have been reading up more, and I'm wondering if I should get an A1C. My next doctor visit isn't until May. I've just (re)started low carb since DH's diagnosis, so perhaps it would be best to wait and see what the level is after I've been low-carbing a while. Any thoughts?

ravenrose · 11-29-2012, 11:02 AM

I don't see any reason to think your A1c would be high. Just as an aside, there is no need to fast for an A1c, so the office test is fine. Get it if it would reassure you.

It's only relevant to test things while you are low carbing if you plan to keep low carbing. Otherwise they are optimistic numbers. It would be interesting though to compare your A1c now to what it is after several months low carbing.

Mistizoom · 11-29-2012, 06:38 PM

Thanks for your reply. I don't need to be convinced I should stick with low carb, so I guess I will wait and request it at my next visit along with any other tests I need. Maybe if I go in earlier for something else I will ask for it to be done then.

Vilya · 12-01-2012, 05:47 AM

If you're curious about your A1C and want to check it yourself, you can buy a home test. There's 2 of them: Bayer's A1C Now, which is an instant-read test, and Walmart's ReliOn mail-away test.

The general consensus seems to be that the mail-away test is a little more accurate, as that is read by a lab. The instant-read test seems to be a little less accurate (but would still give you a good idea).

Just FYI, in case you want to try it.

Mistizoom · 12-03-2012, 08:04 PM

Quote:

Originally Posted by Vilya

If you're curious about your A1C and want to check it yourself, you can buy a home test. There's 2 of them: Bayer's A1C Now, which is an instant-read test, and Walmart's ReliOn mail-away test.

The general consensus seems to be that the mail-away test is a little more accurate, as that is read by a lab. The instant-read test seems to be a little less accurate (but would still give you a good idea).

Just FYI, in case you want to try it.

Thanks for the info. My insurance is really good, so the test is either free or very cheap if I go to the doctor...I'll probably just wait for now.

E.W. · 12-14-2012, 05:13 AM

Over on the Hyperlipid blog there is a little discusion about LC and your A1c. They
bring up that someone on LC with a A1c of 5 may have a fasting blood sugar a lot
higher than someone eating a lot of carbs with a A1c of 5.

Mistizoom · 12-16-2012, 02:09 PM

Quote:

Originally Posted by E.W.

Over on the Hyperlipid blog there is a little discusion about LC and your A1c. They
bring up that someone on LC with a A1c of 5 may have a fasting blood sugar a lot
higher than someone eating a lot of carbs with a A1c of 5.

Good to know thanks. Sounds like it might be best to get the A1C next time, since by then I hopefully will have been LC for 7 months.

E.W. · 12-21-2012, 01:08 PM

Or another option is to go to one of the pay it yourself labs. I saw one lab that will do
it for $32.50 that's go in have it drawn and they email the results in 2 to 3 days.

Magicsmom · 12-23-2012, 09:07 AM

Quote:

Originally Posted by E.W.

Over on the Hyperlipid blog there is a little discusion about LC and your A1c. They
bring up that someone on LC with a A1c of 5 may have a fasting blood sugar a lot
higher than someone eating a lot of carbs with a A1c of 5.

That sounds a bit strange to me, and I'm wondering how that would work. Since the A1c is an average of what your blood sugar levels are over a period of time (60 days, I think), then why would it be relevant that you're low carbing? Your A1c is what it is no matter how you've been eating. If your blood sugar averages are higher, then your A1c reading is going to be higher, wouldn't it? My last A1c was 5.1, and I was not low carbing at the time. I expect my next one to be lower, since I am low carbing and will continue to do so. My blood sugar levels are consistently lower when I'm low carbing.

E.W. · 12-26-2012, 04:13 AM

Terry it does seem crazey at first so I hunted that post for up.

Hyperlipid: Physiological insulin resistance (1)

AllisonB · 12-26-2012, 07:21 AM

Quote:

Originally Posted by Magicsmom

That sounds a bit strange to me, and I'm wondering how that would work. Since the A1c is an average of what your blood sugar levels are over a period of time (60 days, I think), then why would it be relevant that you're low carbing? Your A1c is what it is no matter how you've been eating. If your blood sugar averages are higher, then your A1c reading is going to be higher, wouldn't it? My last A1c was 5.1, and I was not low carbing at the time. I expect my next one to be lower, since I am low carbing and will continue to do so. My blood sugar levels are consistently lower when I'm low carbing.

This was my thought exactly. My last A1C (taken a week ago) was 6.7; 4 months ago it was 12+. My overall eating has changed dramatically and my overall glucose results show that - regardless of what my fasting glucose readings may be.

Leo41 · 12-27-2012, 04:16 PM

My endo confirmed what I read on Hyperlipid. I've always been concerned that my fasting BG is higher than I'd expect since I eat very low carb. My doctor told me that's why he goes by my A1c and doesn't worry about my 93-95 fasting numbers.

The way it's explained on Hyperlipid, I can't quite follow the science, but apparently regular low carbers experience something like the Dawn Phenomenon of diabetics where the liver will dump glucose to keep the blood sugar from going too low--and that results in fasting numbers that are deceptively high.

AllisonB · 12-28-2012, 08:11 PM

Thanks for the info, Leo. I will read more on this. I saw my bariatric surgeon yesterday and my PCP today, both told me they are only concerned with my A1C and not individual readings, but I need to continue to use the post-meal readings to refine my post-surgery food choices. When I mentioned going back on a low dose of Lantus at night, my PCP said no, that my A1C is coming down fast and she expects that to continue w/o the further need for insulin. Yay

11-28-2012, 09:10 PM	#1
Mistizoom Senior LCF Member Join Date: Nov 2009 Location: Midwest Posts: 991 Gallery: Mistizoom Stats: 300/246/190 initial goal WOE: low carb Start Date: November 2012	A1C vs. fasting glucose I have not been diagnosed as diabetic but I have PCOS and have been on Metformin ER 1500 mg/day for several years to control my high insulin levels. I get tested for fasting insulin and fasting blood glucose once a year. My fasting insulin is now in the normal range (though high end of normal, I think) and my fasting blood glucose has come out a 88 consistently. Last year my doc wanted to do A1C at my visit (non-fasting) but I opted to return to get the fasting glucose and insulin done. Not sure why she didn't have them do A1C then but she didn't. DH was just diagnosed with Type II (via A1C) and I have been reading up more, and I'm wondering if I should get an A1C. My next doctor visit isn't until May. I've just (re)started low carb since DH's diagnosis, so perhaps it would be best to wait and see what the level is after I've been low-carbing a while. Any thoughts?

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11-29-2012, 11:02 AM	#2
ravenrose . Join Date: Dec 2009 Location: California Posts: 9,080 Gallery: ravenrose Stats: lost 130 lb so far, and miles to go before I sleep WOE: low carb controlled calorie Start Date: June, 2009	I don't see any reason to think your A1c would be high. Just as an aside, there is no need to fast for an A1c, so the office test is fine. Get it if it would reassure you. It's only relevant to test things while you are low carbing if you plan to keep low carbing. Otherwise they are optimistic numbers. It would be interesting though to compare your A1c now to what it is after several months low carbing.

11-29-2012, 06:38 PM	#3
Mistizoom Senior LCF Member Join Date: Nov 2009 Location: Midwest Posts: 991 Gallery: Mistizoom Stats: 300/246/190 initial goal WOE: low carb Start Date: November 2012	Thanks for your reply. I don't need to be convinced I should stick with low carb, so I guess I will wait and request it at my next visit along with any other tests I need. Maybe if I go in earlier for something else I will ask for it to be done then.

12-01-2012, 05:47 AM	#4
Vilya Major LCF Poster! Join Date: Dec 2011 Location: Texas Posts: 1,691 Gallery: Vilya Stats: 285/184/170 WOE: LC/HF for T2 diabetes Start Date: Sept. 2011	If you're curious about your A1C and want to check it yourself, you can buy a home test. There's 2 of them: Bayer's A1C Now, which is an instant-read test, and Walmart's ReliOn mail-away test. The general consensus seems to be that the mail-away test is a little more accurate, as that is read by a lab. The instant-read test seems to be a little less accurate (but would still give you a good idea). Just FYI, in case you want to try it.

12-14-2012, 05:13 AM	#6
E.W. Senior LCF Member Join Date: Oct 2009 Location: Tyrone Georgia U.S.A. Posts: 961 Gallery: E.W. Stats: 319/313/ a lot less WOE: fast5 Start Date: restart 4/10/13	Over on the Hyperlipid blog there is a little discusion about LC and your A1c. They bring up that someone on LC with a A1c of 5 may have a fasting blood sugar a lot higher than someone eating a lot of carbs with a A1c of 5.

12-21-2012, 01:08 PM	#8
E.W. Senior LCF Member Join Date: Oct 2009 Location: Tyrone Georgia U.S.A. Posts: 961 Gallery: E.W. Stats: 319/313/ a lot less WOE: fast5 Start Date: restart 4/10/13	Or another option is to go to one of the pay it yourself labs. I saw one lab that will do it for $32.50 that's go in have it drawn and they email the results in 2 to 3 days.

12-26-2012, 04:13 AM	#10
E.W. Senior LCF Member Join Date: Oct 2009 Location: Tyrone Georgia U.S.A. Posts: 961 Gallery: E.W. Stats: 319/313/ a lot less WOE: fast5 Start Date: restart 4/10/13	Terry it does seem crazey at first so I hunted that post for up. Hyperlipid: Physiological insulin resistance (1)

12-27-2012, 04:16 PM	#12
Leo41 Senior LCF member Join Date: Nov 2007 Posts: 8,426 Gallery: Leo41 Stats: 340 then/145 now WOE: Low carb/calorie cycling	My endo confirmed what I read on Hyperlipid. I've always been concerned that my fasting BG is higher than I'd expect since I eat very low carb. My doctor told me that's why he goes by my A1c and doesn't worry about my 93-95 fasting numbers. The way it's explained on Hyperlipid, I can't quite follow the science, but apparently regular low carbers experience something like the Dawn Phenomenon of diabetics where the liver will dump glucose to keep the blood sugar from going too low--and that results in fasting numbers that are deceptively high.

12-28-2012, 08:11 PM	#13
AllisonB Big Yapper!!!! Join Date: Oct 2002 Location: SW Ohio Posts: 8,564 Gallery: AllisonB Stats: Day of surgery:255/Today:158/Goal:140 Start Date: RNY 8/20/2012	Thanks for the info, Leo. I will read more on this. I saw my bariatric surgeon yesterday and my PCP today, both told me they are only concerned with my A1C and not individual readings, but I need to continue to use the post-meal readings to refine my post-surgery food choices. When I mentioned going back on a low dose of Lantus at night, my PCP said no, that my A1C is coming down fast and she expects that to continue w/o the further need for insulin. Yay