"Currently, if you want to check water supplies for the presence of toxic bacteria, you have to take a water sample and then culture it in a lab over several days. In the meantime, it's impossible to say if the water source is safe to use. A group of students from the Technical University of Denmark, however, have created a sensor that they say can detect bacteria in water instantly, on the spot.
Developed through spin-off company SBT Aqua, the sensor utilizes a technique known as impedance flow cytometry."
gizmag.com/bacteria-water-s...
Most of us probably recognise 'Flow Cytometry' as the definitive test for CLL. Cytometry just means "the measurement of the characteristics of cells." en.wikipedia.org/wiki/Cytom... (Interestingly the Wikipedia article actually shows a flow cytometer and this article explains more of the science behind the above article.)
There's also a specific Wikipedia article on Flow Cytometry. The test used to specifically diagnose CLL amongst the many other possible blood conditions uses the Fluorescent labels technique, where fluorescent CD marker antibodies are used to identify the unique CD fingerprint of CLL B-cells:
en.wikipedia.org/wiki/Flow_...
Interesting to see that a related technique to that used to diagnose us is also being used to speed up testing of water contamination - something we need to be more aware of with our compromised immune systems. Obviously the sensor shown in the Gizmag article photo will need considerable mechanical and electronic packaging integration to automate the testing process, but hopefully that can be done to produce something a bit easier to take with you on your next camping trip than the current laboratory models!
Neil
Splenomegaly in CLL patients: How far can you go ?
The good and the not so....
Some answers back from doctor. 
Clive James, Broadcaster, Writer and CLL patient dies
