DCA

Hi Meaghan, We use the DCA Vantage for POC A1Cs and last year our diabetes management team reached out to me as they had a similar concern as yours.  They told me they are expecting the A1C to be higher than what it is reading on the POC A1C device based on the average glucose reading from the patient’s CGM device. I did some googling at the time because I had never heard of an A1C result being calculated from CGM readings. There were multiple articles that stated the predicted A1C calculations were unreliable coming from CGM data. I explained to the diabetes management team that the specimen type is different between the CGM and DCA and Lab A1C which can absolutely cause some variation. Could you ask them what they deem as "not matching"? Our diabetes management team complains each year that the POC A1C results don't match our Lab A1C results. The examples they give me are usually some like 6.6% and 6.8%. So I've learned that their definition of "results not matching" is quite different from the laboratory's definition of "results not matching". (because those results are pretty good!)  We tend to see a slight negative bias between our DCA and Clinical Lab A1Cs.   We use the CAP acceptable percent difference of 6% when doing correlations between the DCA and Clinical Lab A1C. 

Hi, we also had many complaints starting about a year ago.  The diabetes providers were very concerned because the Dexcom calculation of the HgA1c did not "match" the DCA Vantage result.  We did all kinds of correlation studies including repeating the result in the main lab and sending them out to the reference lab for HPLC.  Most of the time the results "matched" in our mind, like Kari's comparisons 0.2-0.4% difference.  There were a few that did not match up to 1% difference.  We also told them to wipe off the 1st drop of blood and test the 2nd because with a 1ul sample size any tissue fluid or wet finger could dilute the sample.  There are also a bunch of white papers that say that the calculated A1c does not match the measured A1c.  These complaints coupled with the backordered DCA cartridges made us switch to the Abbott Afinion.

Hi Reine, thank you for your additional information! Do you like the Abbott Afinion? I personally am not a fan of the DCA and would love to switch, but switching costs $$$ which no one wants to spend. Our DCA matches pretty well with our Clinical Lab A1C's....we notice a slight negative bias on the DCA result. How do the Afinion results correlate to your Clinical Lab A1C's? The DCA backorder was definitely a pain. Just yesterday my clinics are starting to receive all of their backordered DCA cartridges and now they don't have enough refrigerator space to keep all of them! haha