I agree that it is a problem. My one touch was within +/-5% when I last compared it to a YSI reading. The problem is it won’t be +/-5% for everyone. There are too many individual characteristics (hematocrit being one of the bigger ones) that will affect how reliable a meter is for any given person. The further your hematocrit (or other factor) is away from normal, the less reliable the meter will be for you. It’s hard to believe that we haven’t moved up from the +/- 20 benchmark but here we are…
When you say normal for hematocrit, does that mean within lab range or is there an optimal number? I know with the FT3, optimal is the upper 2/3rds of the lab range. I just looked at my last set of labs & mine was 43 with a lab range of 37-47.
I have had accucheck be out of the 20% and I have had one touch be within 1% of the lab. Then the next time the one touch was 10%. The FDA should thighten up the rules. They can achieve much better by going to 60 sec meters or possibly better manufacturing with the 5 second meters. Or some compromise on time 30 seconds
I agree if I get a reading of 110 I do not know what to do. Is it 125 and some correction is needed or is it 95 where a correction will make me go low.
Kelly, I’ve never seen this addressed with great precision. I’m guessing that the closer to the middle range you are (keeping in mind the upper limit is I think low 50s for a male), the more accurate it will be. It will probably show more variability as you move away from that center with a sharp drop-off as you go out of the reference ranges. I’ve seen it said that there is ‘no clinically meaningful’ variability due to hematocrit if you are within the reference ranges – or even as low as 20-25 with some meters – but I question what that means because ‘clinically meaningful’ will be different for someone shooting for 70-120 vs someone just trying to stay below 180! I think mine is like 46 or 47 and I get pretty close to the lab using my OneTouch.
I agree that clinical meaningful means something different for different levels of control. I try (but don’t always succeed!) to stay below 100 so I want something that is good at picking up lower numbers. That Wavesense Presto did seem to match my Aviva if I was running high.
Tom - I’m curious about which OneTouch you use and if you check it against your lab every time. Has your meter been consistent as it relates to the lab readings? In other words, is it always within +/- 5%? I’m seriously considering changing meters.
Your remarks about hematocrits sent me to my lab file and my last measurement was 45.3% in a reference range of 38.5% - 50%. The meter that I’m losing trust in says that it automatically takes into account the hematocrit when the sample is measured.
Thanks for reporting your experience with this issue.