There are several threads in the catacombs here about the size of blood drops and funky results. I'm sorry I don't have the time to hunt them out for you right now.
I have seen the same thing happen when I have used a skimpy drop to test. Some days my fingers just do not want to give me blood despite soaking them in warm water, shaking my hands down or making a turniquet with a rubber band. After stabbing myself 5 or 6 times- I get to the point where I cannot force myself to do it one more time- so I just live with the nasty high reading. I always test after breakfast on those days just to be sure that nothing is amiss. I circle them on the chart for my doctor and drop them from my weekly average.