Diabetes Testing

Diabetes Testing Is Useless

Unless people with diabetes are taking insulin, they waste their time and money when they test their blood sugar.


I agree with the conclusions of a review from the Cochrane Collaboration, the most respected group that reviews scientific studies. The review concluded that among people who have had type 2 diabetes for more than one year and aren’t using insulin the effect of testing “is small.” And when they have diabetes longer it makes even less difference. Even worse: no evidence shows that testing “affects patient satisfaction, general well-being, or general health-related quality of life.”

Yet all of us who have diabetes must regularly check our blood sugar.

1. When to test

The first problem is testing at the wrong time. When our A1C level is above 8.4, “fasting hyperglycemia plays a major role,” according to a careful study in the professional journal Diabetes Care. So it makes sense to focus on fasting tests when we are diagnosed.

But when we begin to manage our diabetes, our blood sugar levels after eating are more important, according to another study in Diabetes Care. But our doctors and nurses don’t always tell us that, or maybe we just we don’t hear it.

Testing two hours after the first bite of a meal is when those of us with well-controlled diabetes need to check our blood sugar. But not after every meal, just those when we eat more than a few grams of carbohydrate, which is the only thing that will have much effect on our levels.

2. How high is too high?

The second problem is that few of us know how high our blood sugar should be after we eat. When our blood sugar level is too high after eating, we are more likely to get complications from our diabetes. Since people who don’t have diabetes rarely have a level above 140 mg/dl two hours after eating, the American College of Endocrinology recommends this level as our target.

On the other hand, Dr. Richard K. Bernstein considers this level to be “unacceptably high,” as he writes in Dr. Bernstein’s Diabetes Solution. His personal target, which he also sets for his patients, is 83 mg/dl, because of the lower mortality rate at that level. This is the level that I also strive for.

3. Take action after testing

The third problem is that we usually do nothing other than writing down the number. Testing our blood sugar, keeping a record of it, and even knowing how high is safe doesn’t change on our levels. These are only the first steps. Knowledge of our levels and what they need to be can give us power over managing them, but only if we do something.

If we find that our levels are too high, the one thing that will bring it right down is exercise. It actually doesn’t take a lot, as I well remember when my late wife’s blood sugar level was about 250 mg/dl after dinner one night. She wondered what she could do, and I suggested that we go for a short walk. When we returned, her level had dropped considerably.

4. Use testing to change

When we understand how different foods affect our blood sugar, long term diabetes management becomes just as straightforward. The key is accepting that diabetes is a disease where we can’t handle carbohydrates like most people can. Carbohydrates have an outsize effect on our blood sugar levels. Protein will have a small effect, and fat has none.

As a result, it’s only when we eat lots of carbs that our levels shoot up. The worst culprits are the grains and other starches, like potatoes.

With testing, see for yourself how different foods increase your blood sugar levels. And then take the next steps.

This article is based on an earlier version of my article published by HealthCentral.

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  • Helen Mueller May 4, 2015 at 11:41 am

    I am using insulin. I take levemir at night, humalog as needed. Medicare has me down to three strips a day; I can shoot up to 5 times a day. The endo I saw recently had a fit because my A1cNOW was 5.5. At the lab it is 5.8. I know there are people who, like Dr. Bernstein, have an A1c in the low to mid 4s. I don’t have that discipline. Perhaps if I were only cooking for myself – but my anorexic husband will eat starches, so there they are, on the table in front of me. As I said, discipline. However, I have learned the best time for testing for the max amount of info for me: I test when I get up, which tells me whether or not I need humalog. I test pre-lunch, so I know how much to shoot for my meal, and, again, about two to three hours after lunch, experience has shown that number is usually the same pre-dinner. I do have a stash of strips, so if I need a correction, either insulin or exercise, I can test its effectiveness. My friend, who also uses insulin and has a Dr. Bernstein A1c, tests ten times a day. She now has a new endo, who wants to limit her to six; he obviously does not understand, nor care, what it takes to get that low A1c. BTW, I am 77, she is 70. The AACE thinks that after 65 you can relinquish tight control and, unfortunately, they believe tight control is anything under 6.5.

    • David Mendosa May 4, 2015 at 1:11 pm

      Dear Helen,

      My guess is that the AACE isn’t optimistic about people with diabetes living long lives. Personally, I will be 80 in 3 months and plan to live as long as my father did, so I am not about to relinquish tight control. Also, here is a link to an old article about Medicare, but it might help you get more test strips: http://www.mendosa.com/medicare.htm

      Best regards,

  • todd May 3, 2015 at 2:53 pm

    I did read the entire article, and I did test like a mad-man until I figured out what certain foods do to my bg, but now that I am on a routine I no longer have to test so often since I know what foods do or don’t do. I have known that I have this incurable disease for 10 yrs now, the article is mostly for those that haven’t accepted their condition or are just learning about the disease. I was merely giving you credit for pointing out when and why you test. Once you learn about yourself, then you mostly stay in cruise control.

    • David Mendosa May 3, 2015 at 5:17 pm

      Dear Todd,

      Thank you for your explanation. I now understand and appreciate your comment. In fact, what you have done is an excellent description of what I did too.

      Best regards,

  • Diane May 3, 2015 at 11:42 am

    Hi David,

    You said 83 two hours after a meal. Wow! That sounds so low to me. My fasting BG is consistently around 120, so I have no clue how I could get 83 two hours after a meal. Is this realistic? I’m not sure what to do about this information. Help!

    • David Mendosa May 3, 2015 at 1:47 pm

      Dear Diane,

      Yes, a level of 83 two hours after a meal is realistic in my experience. I generally have my level very close to 83 then. Of course, that is by following a very low-carb diet, which is the only way that such a good level is possible.

      Best regards,

  • todd May 2, 2015 at 8:02 am

    Hi David,
    I agree that once you learn your body, the testing isn’t necessary on a regular basis. I am down to only checking my morning fasting since I am on NPH insulin at night in order to battle the dawn phenomenon. I am also on the max metformin. I am “celebrating” my 10 yr anniversary this summer. I have removed starches from my diet, try to get out daily to walk and yard work, but an 83 makes my head spin. I think I was undiagnosed for many years so my body prefers BG above 100. I suppose eventually I will work my way down. My latest A1c was 6.0 and my lowest was 5.8. Thanks for confirming my lack of testing.

    • David Mendosa May 2, 2015 at 9:17 am

      Dear Todd,

      Unfortunately, you totally misinterpreted what I wrote. I certainly did not mean to confirm your lack of testing. I think you just read the headline or first paragraph. Please read the whole article.

      Best regards,

  • Robert Fierro May 2, 2015 at 7:17 am


    re: “Took reading with one tab. Ido not have diabetes . IMy reading was 130. I immediately took it two more times my readings were 87 and 90. Could the tab be defective? ”

    Some years ago, David was good enough to inform us that the FDA requirement for blood glucose meters is +/-20% accuracy. This means if you take a reading and your value is 120, then +/-20% says that your ACTUAL blood glucose value is anywhere between 96 and 144! At that time he also told us about a meter made by Wavesense ( now AgaMatrix) that was substantially better. If you go to http://www.agamatrix.com/wp-content/uploads/2015/01/7500-03165_Rev_D_Artwork_Whitepaper_Performance_AgaMatrix_Presto-2.pdf
    you will see their pubished results are substantially better than the FDA standards and the performance of any other system that I am aware of. That said, what their data says is that not ALL the readings are as good as they can be, but due to the variences of manufacturing and a number of other factors, some test strips in a container of 50 for example are going to be not as good as most, or to put it another way, some will give poor results. My experience, from using this system since it was generally available to the public, is that on average, at least one test strip in 50 will give a result that is on the high limit of the value. So, when I get an unexpected result, I retest. I believe that on a regular basis, one should take 5 strips at random out of a container and test them against the test solution ( or lacking fresh test solution, against the same pinprick of blood). Write down the values obtained and see how close they are to one another. The spread beetween the highest and lowest divided by 2 represents your meter’s functional accuracy.
    When I did this test with my other meter some years ago, I immediately switched to the AgaMatrix. For the record, I have no relationship with this company other than that of a paying customer. BTW… I had a problem with one of their meters some years ago and their customer service was polite and almost instantaneous. (They replaced the meter at no cost to me).

  • Alice miller May 2, 2015 at 7:04 am

    I have had diabetes 2 for about 30 years. I take metformin twice a day and have an A1C of 6.8. I eat multigrain cereal for breakfast, fruits and most veggies, very little meat. Foods that raise my blood sugar are ice cream, other sweets, pizza, potatoes, and pasta. I check blood sugar each morning. Now that I have read your article I am going to check it two hours after breakfast. I am 90 yrs. old and self sufficient. Alice

  • michael May 2, 2015 at 5:25 am

    Hi. you say that type2 diabetis cannot be cured, yet when people have a gastric bypass they have found that the diabetis is cured, also if you eat less than 800 calories a day this has the same effect Your Comments Please Michael

    • David Mendosa May 2, 2015 at 8:09 am

      Dear Michael,

      Thanks for bringing this question up. While diabetes has no cure, we can put it into remission. There’s a difference. With remission if we go back to our old ways the diabetes returns. Even people who have gastric bypass surgery can and sometimes do defeat the purpose of the surgery and their diabetes comes roaring back. You may want to read my article “Why Remission is Better than a Cure.” You also mention an 800-calorie diet, and I think you mean the 600-calorie diet, which I quite recently wrote about at “Diabetes Remission by Losing Weight.”

      Best regards,

  • Barry Becker May 1, 2015 at 5:56 am

    Hi David,
    I’ve had type 2 diabetes for more than ten years. The only time I ever got close to (or below) 83 was when I tried Starlix, and had an alcoholic drink with my meal. I quit Starlix soon after that and decided I would not take any medication with the string of letters “glyp” in it. I am on Metformin only. My last A1c was the lowest ever (5.8). I try to keep my post-prandial blood sugar below 125.

    Thank you for your informative and important articles.


  • Ambre May 1, 2015 at 3:27 am

    The parts of all grains that we eat are seeds, but all seeds are not gains. All fruits are seeds for instance.

    As for amaranth they are actually a giant grass of which we eat the seeds (or use as a dye). So while technically Amaranth is a grass it is not a grain as it contains some protein and few of the bad carbs and fewer starches so less sugar. It has not been as highly selected for sugar content as modern culitvars such as corn. When you look at its wild ancestor is much smaller, obviously a grass, and has next to no sugar compared to mass farmed corn. Tepiary beans have a much lower glycemic index compared to modern mass cultivated commercial bean such as pinto, black, or similar.

    As a rule the more primitive an edible plant is the lower the glycemic index. Farmers bred for sweetness, then later yield, at the expense of nutrition and even plant health and seed viability is less important that regularity in size, sugar content, and ease of portability to supermarket. Flavor and nutrient content are practically never considered.

    That’s all I remember from college biology classes.

    • David Mendosa May 1, 2015 at 7:23 am

      Dear Amber,

      Thank you so much for your wonderful explanation! You have a great memory and have the ability to write very clearly. And correctly.

      With metta,

  • Mark April 30, 2015 at 8:30 pm

    Are you saying 83 after two hours following a meal? I could see that being a fasting target, but after a meal? Wow – that would mean practically eating zero carbs and if you didn’t start at 83, you’d have a heck of a time getting there.


  • Carol Wong April 30, 2015 at 2:15 pm

    I have been on Janucia 100 mg every morning for three years. My primary was satistfied with my lab tests and put me on an ” see as needed” basis.

    My oncologist has been following my blood sugar for five years too. At the beginning, I did have readings that showed diabetes but now my blood sugar has been falling. Last week, it was 70 and I have had sweaty hands a lot. Is it possible that I am starting to drop into hypogycemia?

    • David Mendosa April 30, 2015 at 2:18 pm

      Dear Carol,

      No, that doesn’t happen. Diabetes can be managed — and it can be managed very well. But it can’t be cured. What you need to know from your doctor is what you average blood sugar level has been for the 2 or 3 months before being tested. The test is called the A1C or the hemoglobin A1C.

      Best regards,

  • Ruth Greenberg April 29, 2015 at 8:01 am

    Took reading with one tab. Ido not have diabetes . IMy reading was 130. I immediately took it two more times my readings were 87 and 90. Could the tab be defective? I do have hypoglycemia.

    • David Mendosa April 29, 2015 at 12:00 pm

      Dear Ruth,

      What is a “tab”? Do you mean a test strip? If so, the strip or the meter could be defective or the strip beyond its expiration date. A second possibility is operator error. Please see http://www.mendosa.com/blog/?p=1441 . A third possibility is that you have actually developed diabetes, certainly because hypoglycemia often leads to it. I suggest that you check with your doctor.

      Best regards,

  • Jane April 18, 2015 at 12:22 pm

    Amaranth is bland when cooked but is reminiscent of cream of wheat in texture. So I use it as a breakfast food and add cinnamon & berries. I don’t like it any other way.

  • Jane April 17, 2015 at 4:38 pm

    What do you think about amaranth? I read that it was a seed, not a grain. Thanks.

    • David Mendosa April 17, 2015 at 5:00 pm

      Dear Jane,

      Yes, I do understand that amaranth is a seed, although after reading the Wikipedia article about it I am more confused than ever. Maybe some varieties are grain, but I don’t know. Anyway, I don’t think that I have ever eaten it, so I can’t offer any informed opinion.

      With metta,

  • David Mendosa April 17, 2015 at 4:07 pm

    Dear Jane,

    I’m glad that your message got through just fine! Most people are in denial at first, and I see that you have gone well beyond that stage. What you call grains are in fact all grains. None of them are as high glycemic as wheat and rice, but they aren’t low glycemic either. They would be good to check with your blood glucose meter.


  • Jane April 17, 2015 at 3:04 pm

    I agree that a primary result of testing for me was changing my eating. This was a process for me and didn’t occur quickly as for others. I had to prove it to myself a bunch of times that pizza wasn’t something I could eat! I also learned from testing that I could eat a 1/4 cup of oatmeal but not a cup. I know this sounds obvious, but I have to factor in that I have a food addiction and so I was in denial for sometime.

    However eating oatmeal is in the past; I’m now adapting Dr. Bernstein’s diet to my own. I saw how oatmeal raised blood sugar enough times to admit the truth. The grains I still eat are quinoa, buckwheat & amaranth[a seed].