You probably never use the control solution for your blood glucose meter. You can blame your doctor or yourself for this oversight, but the chances are that you never have heard this term before.
Our doctors and other medical professionals rarely discuss using a control solution. It usually doesn’t come with our blood glucose meters. And your local drug store probably doesn’t carry the one that your meter uses.
But the U.S. Food and Drug Administration, the International Organization for Standardization (ISO), and the American Diabetes Association all recommend that we often check our meter with its control solution. Probably every owner’s manual for all of the blood glucose meters on the market has the same message. Something is seriously out of whack here.
A control solution is a solution that mimics blood and that is used to test the accuracy of a blood glucose meter and test strips, says the Manual for Pharmacy Technicians. It is specific for a particular meter and may come as low, normal, or high control. The solutions can be categorized as “Level 1” or “Level 2,” representing low or high control. The expiration date of the control solution varies by manufacturer and can range from three to six months.
Most Never Use Control Solution
A survey of 18 people in the Bay Area of California who have type 1 diabetes or parents of children with it showed that 58 percent of them never used a control solution. Note well that these are people who rely on insulin, which requires rather precise blood glucose meter readings.
Only the abstract of this survey, “SMBG Out of Control: The Need for Educating Patients About Control Solution,” in the September-October 2013 issue of The Diabetes Educator is online. But a friend sent me a copy of the full-text.
Another survey, “An Evaluation of the Barriers to Patient Use of Glucometer Control Solutions,” this one of people with diabetes in Tulsa, Oklahoma, showed that only 23 percent of the 60 people with diabetes use a control solution. This survey was presented at the 2014 annual meeting of the American Association of Clinical Educators. Two-thirds of the people in the survey said that they didn’t use it because they didn’t know about it.
Almost half – 44 percent — of the 29 doctors who responded to the survey said they never recommend using a control solution. They aren’t sure that it’s needed with newer blood glucose meters, or they check the meters against the clinic’s instrument, or they didn’t think about it.
14 Situations to Use Control Solution
Checking a meter against one in a clinic or lab is one of three ways that the FDA recommends to see if the meter is working well. Another is to rely on the electronic checks built into the meter. But this agency of the U.S. government that is responsible for the country’s blood glucose standards recommends that you “test your meter regularly with control solution.” The FDA suggests that you use a control solution:
1. Every time you open a new container of test strips
2. Occasionally as you use the container of test strips
3. If you drop the meter
4. Whenever you get unusual results
Added to this list are eight more situations when you need to use a control solution, according to what six of the major meter manufacturers recommend:
5. Check monitor performance to make sure it is working properly
6. Results do not seem accurate or reflect how patient feels
7. Confirm that test strips are working properly or to check whether they are not working properly
8. Practice testing without using blood or for proper technique
9. Vial of test strips is damaged, left open, exposed to extreme temperatures or humidity
10. New monitor
11. Once per week
12. Advised by health care professional
As if this isn’t already enough, I found yet two more recommendations
13. Occasionally as you use the vial of strips
14. When the machine has just been thoroughly cleaned
We have a big disconnect here between what the organizations and meter manufacturers say to do as this recommendation is funneled down through our doctors to the people with diabetes that it directly affects. To help resolve this issue I turned to two good friends of mine who work on the front lines with us.
A Recommendation to Use Control Solution
The best way to make sure our meter and strips are working properly is to test it against a big lab equipment at the same time, notes Margaret Leesong, a vice president of i-SENS, which makes blood glucose meters and test strips. “But this is not easy for us to do, while control solution testing can be done at home. Aside from any error messages that the meter shows, control solution is the only thing we have to check if we can continue to count on our meter and strips.
“I think that control solution testing is like wearing a seat belt,” Margaret continues. “Even when we are not likely to have an accident, we take precautions.”
A Recommendation to Recheck Blood Glucose Instead
On the other hand, Karen LaVine, a Certified Diabetes Educator in Albuquerque, New Mexico, is less supportive of using a control solution.
“I rarely talk to patients about using a control solution,” she told me. “But I do frequently discuss what to do if someone gets an unexpected blood glucose result.
“I recommend the following steps,” Karen continues. “Recheck your blood glucose, following the recommended procedure exactly. Wash hands well (even if it’s a second time), dry with clean paper towel, put fresh lancet into lancet device, and recheck blood glucose with a fresh strip, being careful to obtain an adequately sized sample easily. If the second reading is significantly different from the initial reading, then recheck your blood glucose one more time to help estimate your current blood glucose.
“Having to use two to three strips occasionally is almost always going to be a lot quicker than fiddling with a control solution. That’s because once you open a bottle of control solution, it’s only good for three months. So if you get a questionable blood glucose result and want to run a control test, your current bottle is highly likely to be expired.”
Karen’s conclusion is that for patients testing at home the use of a control solution could be helpful only very rarely. I tend to agree, but think that some people will benefit from using it in some situations.
When a doctor told me almost 22 years ago that I have diabetes, he didn’t even mention that such a thing as a control solution for blood glucose meters exist. In the many years since then no doctor or other medical professional who I have seen as a patient has ever said anything either. Maybe this is because I have never used insulin.
Should People on Insulin Use Control Solution?
After considering all aspects of this knotty situation, my feeling it that I don’t think that we should go to extremes and say that everyone who has diabetes needs to check his or her blood glucose meter in all of or even most of these situations.
But certainly all people who uses insulin to manage their diabetes have to be sure that the blood glucose meter they use is reasonably accurate because too much insulin can lead to a dangerous low blood glucose level and too little to a dangerous high blood glucose level. Those of us who rely on insulin do need to be sure that the blood test results they get are as accurate as possible.
I’m not so sure about the rest of people with type 2 diabetes who aren’t on insulin. Does anyone with diabetes who is reading this far and isn’t on insulin regularly use a control solution with his or her blood glucose meter?
This article is based on an earlier version of my article published by HealthCentral.
This article is based on an earlier version of my article published by HealthCentral.
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I was diagnosed just a week after you posted this.
My doctor had me do a control test and then showed me how to test myself in the office. She recommended a control test with every new set of strips.
Thus far, I have been doing that. NOTE: I use a Bayer Contour Next meter and their control solution. They had a “recall” on the instructions with their control solution in 2015 and now instruct that you shake vigorously for 15(?) seconds before using.
Hi David – The old meter was the OneTouch Ultra2. It was probably ~6 years old (My first meter). For a very long time, it was always pretty close – several times I measured before going in for a Random BG draw and it was pretty accurate to the LAB results.
I do not think it was the strips as I get fresh strips pretty regularly and I changed lots and still get results that are too low. Either the meter just got old (there is an expiration date on the meter box) or a trip to Hawaii with the very high humidity caused it to lose calibration.
The replacement was the OneTouch VerioIQ (both provided by Kaiser). The variations are between old and new are wide. For example, old meter shows 81 and new meter shows 128. Once the old showed 63 and the new showed 80. So the delta is not consistent, but the higher the BG level, the wider the delta.
I have been testing side-by-side for about 2 weeks now and the two devices have always returned widely different numbers. I have not controlled either as I did not want to break the seal on the solution yet.
The result was that unfortunately I was getting false confidence with the old meter, hence eat a bit more carbs, and then got a higher than expected a1c (7.2). Thus the importance of your article. We need to validate the accuracy (either via control or comparison to lab test) to ensure accuracy. The impact for me was a a1c result of 7.2 instead of 6.1. Somebody on insulin could have a potentially bigger issue.
I appreciate this follow-up message, Steve. The problems with using an old meter that you encountered can be a lesson for all of us. I well remember an endocrinologist telling me in the 1990s not to use a meter that was more than one year old. Maybe they have got better since then, but six years old is a long time.
I tried to buy control solution but my drug store does not stock it. I always test my glucose with my meter before I have blood drawn for an A1C. Sometimes the results are very close but all have been within 15 percent with the glucose level above 75.
I have never used a control solution. Recently, my readings became very low – essentially saying I was at normal levels all the time. Then recently I had a Random BG and a1C and got a much higher than expected result. I immediately got a new meter. There was a bout a 30 point difference between the old and the new meter (old being too low). That explains the unexpected a1C. I will now be using the control solution to check the meter every couple of months.
Interesting, Steve. What was the brand of your old meter? And now old was it? Could the problem have been with the test strips?
Most people,at least in India,don’t use control solution because they don’t want to waste a rest strip as it’s quite expensive and we have absolutely no insurance coverage.