To my knowledge, different methods of calculating blood glucose should not give such a wide variation in the test results. However, the blood sample is handled by humans, and human error can always occur! Since the two teststell you diametrically opposite things: the first that she does not have diabetes, and the second that she does, I suggest you get fasting and PP glucose tests done from a good lab (!): in this case, maybe divide thesample into two, and give to both these labs, for a confirmation of her status. Tell them what you are doing, so both sets of samples are handled with extra care!