I've seen this before and I've tried to use it to fight with my home hemo nurse when she has tried to monkey with my dialysis prescription in order to meet Kt/V. I keep fighting with her about the fact that Kt/V is useless for those of us on short daily home hemo. Goes in one ear and out the other because she is measured on Kt/V and they don't give a rat's behind about how I actually FEEL.