In the "brittle diabetic" thread was mentioned a testing device using a mass spectometer.
Hewlett-Packard did a similar study of this over 10 years ago. Frought with complications, using healthy patients and confirming results with blood tests, perhaps workable?
spectroscopyonline.com article from 2010 was very interesting, but using urine, so, it's stll being studied, though it may not be well known that sunlight has some crazy line structure?
Variations of 8 times brightness across subnanometer wavelngths owing to the nature of sunlight, so a tool for use in daylight might be very inexpensive?
Comparison of nomal and less-so, using the standard fasting test?
The filtrs that are the guts of the devices have been made for over 50 years, but are getting narrower.
Not a replacement, just something that can compare one's normal to other things.
The solar idea may not work, use shortwave UV and get a fluorescent reaction instead? Sensitivity of the equipment is pretty attractive now.
But what's grosser, a glass rod up your urethra, or a pinprick?