> Now an easy to use, cheap device that does this, that sould be patentable.
Agreed. The iWatch (not cheap, natch) does an ECG, so this should be doable on an iPhone in software, ergo no patent should be allowed (in the current right-pondian world, at least). The idea seems to be "apply a mathematical algorithm to a collected ECG trace to determine blood-glucose levels".
You can get an ECG device for ~£100 on Amazon, possibly down to around £50 so just need the data feed from that