Here's the closest device yet to a Star Trek tricorder. Developed by the U.S. Department of Homeland Security's Science and Technology Directorate, this 15"x8"x6" device can check body temperature, heart rate and respiration of victims up to 40 feet away. This "Standoff Patient Triage Tool" (SPTT) could be particularly useful for detecting vital signs of disaster victims buried within tons of rubble.
Instead of spending the 3 to 5 minutes per person just to determine how injured someone is, this can do that in 30 seconds. It works with frickin' lasers, using Laser Doppler Vibrometry to determine vital signs. It will be rolled out for its first trials this fall, but it's still under development, with a goal of eventually shrinking it into the size of a thin laptop.
Sure, it has a long way to go before it can detect obscure diseases, as the Star Trek tricorder pictured above right can, but this is yet another confirmation that some Star Trek technology is on its way. The SPTT is off to a good start, with its creators hoping for commercialization sometime after the middle of next year.