A1C Result and Mornings High

Yesterday I got my A1C result from the lab. It was 5.2..hurray!!!!
But wait...today while I was compiling fasting/morning readings from the past month, most of them were in a higher range.

Here is my monthly fasting reading:

  • 205

I'm confused now...I think I achieved my target of keeping A1C low but morning readings are alarming to me.I came to know that through various sites/blogs that morning readings are the best indication of how well you are managing diabetes.

Any suggestions/recommendations/advice greatly appreciated.

You are a good case study why A1C isn't, in and of itself, always the best measure of BG control.

A1c is a fairly objective in that it's largely beyond the control of the patient other than what the patient does to control their BG. That's because it's measuring how much glucose gets attached to the hemoglobin in red blood cells as they circulate in your bloodstream over the course of their roughly 90 day existence. You can certainly do things to manipulate your BG to cook your A1c to a certain extent, really, the last 30 days has a much greater affect on your A1c then the previous 60 days.

One of the issues, of course, is that since it's an average, you can only determine your average BG over the last 90 days. Since you are having high fasting numbers, your average BG and A1c is being balanced out by lows elsewhere in the day. Alternatively, since the attachment of glucose to hemoglobin is also time dependent, you could be spiking in the morning followed by relatively longer times spent at lower BGs the rest of the day. Alternatively, alternatively, the correlation between A1c and average BG is only a correlation. Like every other variable, for humans, there is a lot of variation around the average. So, it could be that your A1c of 5.2 is simply equivalent to a higher average BG than what's predicted by correlation for humans as a whole.

So, you're right, you have to do something about your fasting numbers. Maybe you have Dawn Phenomenon. Maybe you are spiking all the way through the night. In other words, looks like more testing is called for and you might want to take a look at your basal settings.


First of all, I’m surprised that you have such a low A1c with those fasting readings. My guess is that your BG elevates not long before you test and most of the night you’re in range. I’m also guessing that your post-meal readings are excellent.

The A1c is simply an average. If I were you, I’d address those high fasting numbers with a more aggressive overnight basal profile, whether via a pump or MDI. If it were me, I’d do the adjusting and experimenting myself. If you’re not comfortable with that, then seek out the advice of your medical team.

I would not accept these numbers without taking action. They are not harmless even though you have a “normal” A1c.

That would be my guess as well Terry, spiking BG in the AM, probably DP, followed by fantastic control the rest of the day and night.

Still, it is not outside the possibility that he's just a low glycosylator.

Either way, I concur, more testing and rectify those fasting numbers ASAP.

Thanks Terry and FHS for your detail response. When I looked at Dexcom CGM post dinner readings, it usually start getting higher after 2AM and continue in higher range till 11 AM or before my lunch time. My endo actually reduced the basal rate.

On the other side, I usually don't eat anything after workout (around 8-9PM). Just take green/herbal tea before go to bed. This is dilemma for me. I have attached reading for the past 10 days of hourly statistics I took from Dexcom.

865-HourlyStatistics.JPG (93.4 KB)

Thanks for attaching the 10-day graph. This is a graph I look at regularly. I would address your 5-8 p.m. lows first. When the bottom edge of the rectangular boxes, the 25th percentile, penetrates your lower BG threshold then that means you are having significant low BGs during these three hours.

These lows could be the result of over-correction from your early morning highs? Is that possible?

I don't agree with your endo reducing your overnight basal rate. I'm not a doctor, but then again I believe that the average endo has little to no experience actually managing BGs 24/7/365. T1D is first and foremost managed by the PWD himself.

A doctor cannot get into these issues very deeply or they'd quickly become mired in the data of one patient and not be able to manage a whole practice. This is a value decision that you need to make. If you want to keep getting the results you're getting then keep on with the 4x/year 30-minute consultations with your doc. If you want to make real progress then you'll have to throw yourself into learning how to manage this yourself!

I would work on the dinner-time lows first. Try to keep every CGM reading above 70, if possible. 3-5 p.m. basal rates may be a contributing source of this problem. (see below)

Another thing I see is that you have wide swings in your BG most of the day. 150+ point swings are not good. Your 2-4 p.m. ranges are more what you'd like to shoot for.

I would also consider doing some basal rate testing. Poorly set basal rates are often at the root of all this BG variability. Gary Scheiner's basal rate protocol is a solid way to do this. This is not an easy process and requires some tenacity to stick with it, but the rewards are well worth the effort.

I can't square a 5.2% A1c with the 10-day graph the OP attached.


Again, could be a low glycosylator. Take a look at the this graph of Avg BG vs A1C. The line of correlation represents the average, but look at the amount of scatter around the average.

I never thought about variance of the amount of glycosylation in the population. I thought is was a medically standard thing. Maybe that answers why my A1c turns out higher or lower than I expected. Maybe there are other unknown variables in the glycosylation process.

OMG, your CGM looks exactly like mine. I have a heck of a time during the night, around the same time you do, often I'll drop at around 12am and then start to rise and no amount of levemir helps this because if I increase my PM dose I just go lower and then higher. I'm having to wake and take a shot of novolog or I'll be 200+ when I wake up, the other morning it climbed to 267..ugh! Those middle of the night highs also will keep my high until around 11am and very difficult to correct back down, no? I used to think it was my AM coffee spiking me but it's not that. My lowest numbers are around 8 - 9 pm too, often I can eat anything with hardly bolusing or I go low, too. This is the main reason I want to go on a pump. Are you going to increase your basal rates for this time zone? good luck!

Also, if you read G. Scheiner's "Think like a pancreas", he addresses this BG pattern. I also thought it was a pattern my levemir was causing, i.e., burning out, overlapping, etc...but you're on the pump so no long acting. Apparently this is a very typical pattern for a type 1, it's how our bodies work (or don't actually). :) Additionally, aren't you using your CGM to alert you when you're high, especially in the middle of the night on a pump, are you correcting theses with adjusting your basal rate(s). Don't these highs wake you up, they do me..soaking wet with sweat. ugh!

Yup, my basal rate is cranked up between 2am and 6am to compensate. I actually have a higher rate than my early am basal from 6pm to 10pm. My basal rate is at it's lowest between 12am and 2am, a couple of hours before DP sets a hot poker to my BG.

yup indeed, it sucks when on MDI. Seriously, i haven't slept through a night for so long! I know, know a pump will help this. Today, however, I'm having lows and a really bad one this morning, like a .5 unit correction is dropping me over 50 points (whateva...). never ceases to amaze me how bizarre this disease is and how much it can just wear us down (at least for me). ugh!

Yeah, I gotta say that going from MDI to a pump for this one issue was a life altering experience. I never could get my long acting dose to work properly enough to smooth out the 12am to 9am block of time. That's over 1/3 of your day's worth of crappy readings if you weren't waking up early in the am to either dose more or treat a low.

The pump isn't perfect and can't deal with all the gremlins. I still wake up in the early am to test out of habit. But it's much nicer to see numbers in range most of the time then it is having to correct most of the time.

Let me share my daily routine and daily basal/bolus rate. That might help understanding where the problem is.

Breakfast: Between 7:30- 8:30 AM ; Bolus: 1 unit for 7 grams of carbs
Lunch: Between 11:30AM-12:30PM; Bolus: 1 unit for 13 grams of carbs
Dinner: Between 6PM-7PM; Bolus: 1 unit for 8 grams of carbs

Basal Rate: 12 AM- 6AM: 0.65 unit/hr
6AM - 12AM : 0.95 unit/hr

Terry, I'm pretty much on the same page with you. I have endo appointments every three weeks for the past 7 months. I have give him my breakfast high clearly but he didn't agree to increase basal rate.

Other than that, I usually decrease temp basal during workout by 50% for 2 hours. I don't take snack afterwards and take herbal tea before go to bed around 11:30PM.

Now my food plan that I'm following for the past 7-9 months:

Breakfast: wholewheat bran cereal and granola cereal (80/20 ratio) (80 grams)

Lunch: Wholewheat chicken wrap/chicken/fish sandwich (70-90 grams)

Dinner: lentils/beans/chicken/fish with whole wheat flat bread or most of the time just mixed fruit/vegetable Salad (70-90 grams)

I usually don't take snacks during a day.

I'm frustrated and couldn't figure out where I'm making mistakes either on meal plan or basal/bolus rate..

Also Terry not sure about 5-8pm low's, as I take good portion of meal and feel stuff before going out for workout between 8:30-10:30PM.

Allow me, if that's okay.

Your 4pm to 7pm data are extremely variable. You have a huge range between your highest BG and your lowest BG reading, but from the looks of it, you are more often then not having lows. If you are eating at 6pm, then you have all kinds of basal rate issues starting even before you get into your pre-meal bolus. You want your pre-meal fasting to be your lowest BGs of the day, but you still want them to be reasonably within range of 80.

I agree with Terry that, from the looks of your profile, the root of your BG roller coaster goes all the way back to the bolus corrections you are making for your Dawn Phenomenon. You have a steadily declining avg BG all the way through lunch and into dinner, with crazy high variation before lunch and before dinner. This usually means BGs that are way off the mark leading to lots of corrections up and down at the times of the day when BG should be the steadiest.

The bottom line, you should give basal rate testing serious consideration. Until you can generate a smoother baseline BG than you have, without significant corrections, your bolus dosing for meals is going to be hit and miss with no real way to calculate an accurate or precise carb ratio or even correction ratio to bring your BG back in line after even the smallest deviations.

You're eating about 240 grams of carbs per day. Some people with diabetes can eat that level of carbs and still maintain good post meal glucose levels, but most cannot. What are your BGs two hours after breakfast? If they're 250+, then maybe you need to alter your diet. Have you ever tried eating bacon and eggs for breakfast and seeing what your BGs do after that meal?

Perhaps you could try to cut your carbs down to 40 grams per meal and see what happens.

Sorry if I've given you too many suggestions at once. The first thing I would do is basal test so that you can get your basal rates flat, even if you miss a meal. Has your doctor ever done any basal test or has he just tried to wing it? You can't set basal rates successfully without fasting.

A1C measures average glucose attachment to Red Blood Cell proteins, but assumes not only that you are average and linear in your BG to RBC connection but also that your RBCs survive for the three months prior to testing is also average.
It you have any process that shortens your RBC survival then your A1C will be lower than you can account for by your daily BG readings. Alpha or beta thalassemia, sickle cell, hereditary spherocytosis, hereditary elyptocytosis, G6PD deficincy, private kinase deficiency, to name a few disorders that effect/shorten red blood cell survival.

Sorry half of my post did not show!
Hgb A1c measures glycolisated hemoglobin A1, everyone usually has A1 as the majority hemoglobin -90%+ with Hgb A2 and Hgb F as minor percentages. If you have a Hemoglobin variant like Hgb S, C, D etc, or persistence of Hgb F, or any variety that causes your red cells to be destroyed before the average 90 day lifespan then it will mess with your A1C result.