Is the over the counter test as effective as the one we get in the doctors office?
I purchased one. Over the counter said 9.1. Lab said 6.7.
This is just my educated guess, but I would confidently say that no, the OTC test will not be as accurate as the lab test. Its not likely that the OTC test could comply with the tight controls and standards that the lab test uses. It is possible that the at home test and lab test would correspond, but I think you would find that the home test would be significantly less consistent in its accuracy.
There is one study that I found that discussed the accuracy of the A1cNow at home system specifically and they found, “Using data from 6,231 subjects, they reported that 32% of values differed >0.75% from the laboratory reference (Bio-Rad Variant ion exchange) and that 20% were >1.0% discrepant.” The authors note that they would not recommend the use of this particular at home system (at the time of the study).
Here is the reference:
Fox, L., et. al. Relative Inaccuracy of the A1cNow in Children With Type 1 Diabetes. Diabetes Care 30:135-137, 2007
The accuracy is supposedly plus or minus 1% (as in lab 6% may come out 5% or 7%. Seems like a waste of money to me. I tried two of them and they were both .5% off lab.
I agree - a waste of money. I tried one by Metrika, where you drew up the blood in a little tube and mixed it with a solution and then let it sit and got the results in about 15 minutes.
I also tried one by Home Diagnostics, where you put a drop of blood on a paper and mail it in and they mail results back.
Both were off by more than a point - one higher than the lab and one lower.
If these tests are as inaccurate as the study referenced above indicates, then I would disagree. An inaccurate HbA1c result could actually do more harm than good, at both the high end and the low end, and really doesn’t give you any information that cannot be derived from daily blood glucose readings. Even in the uninsured, inaccurate info is not necessarily better than no info at all.
I just saw my specialist and am associated with a MD doing a clinical trial for Merck. Both use the A1C tester by Metrika. It is sold otc now, and is commonly used in “labs” @ $60 a pop ($11 diy). I have been told that one needs to stay with one lab or one testing method, to obtain consistent results. Labs differ, as do testing protocols. As with automobiles, if you find a mechanic or dealership that does a good job, go to them, just because there is a brand name dealership, doesn’t mean that they are better. There are good MDs and good tests, trust and verify. I have no educated guess, results are what my doc goes by, as do I.
Just go with the lower figure, or the one that you like best!
A few months ago, at one of my monthly diabetes support group meetings, an equipment rep. suprised us when she told us that glucose meters can vary by as much as 20 points (depending on the manufacturer).
You’ll love my answer.
It depends… like most things. There is no such thing as the OTC A1c test just like there is no such thing as the office based A1c or the Lab A1c. Did the lab or office properly and recently calibrate their equipment? What is the coefficient of variation (CV) for their method? Does the lab or physician’s office participate in Proficiency Testing (PT) which involves a reference lab sending known A1c blood samples (the lab is blind to the known values) to see how close they come to the reference value? This could be a long post but I’ll spare you.
There are many facets of diagnostic testing that contribute to accuracy and also precision. The only accurate A1c test is the one that makes sure that the sample is first of all valid for determining A1c and also free from over 800 causes of potential interference to getting an accurate %A1c determination.
I have written extensively on this topic at the Challenge Diabetes Blog (http://challengediabetes.com) BTW, we performed an exhaustive search before arriving at the A1c that we use for supporting clinical trials and home-based patient-endo programs. We eliminated most of the ones already mentioned here due to poor quality and/or instability. We ended up creating our own with our specialized laboratory and we call it HomeCheck-A1c. This is the world’s most accurate A1c bar none.
Also, how many people know that the DCCT protocol that supposedly outlines much of how type 1 diabetes care is supposed to be delivered today involved A1c checks every month or every other month… not every 3 months? If used properly and with the right timing, the A1c can be incredibly valuable feedback on what you’ve been doing to help you in determining the effectiveness of your care. In my opinion, A1c is highly underutilized and used improperly by most physicians.