It’s pretty quiet out there these days, particularly after you’ve gone to bed. But somewhere above, a pilot bathed in the glow of avionics is looking up from his instrument panel into the night. Behind him are 76 soft-sided coolers holding the physical data on which modern medicine depends—samples of blood, urine, and tissue from individuals around the country.

They’re aboard a Pilatus PC-12 turboprop business aircraft, collected from airports where they’ve been delivered from laboratories, doctors’ offices, and hospitals. The airplane is part of the 25-strong specimen-transport fleet of Quest Diagnostics, one of the two leading companies in the medical lab services market.

Quest pilots’ mission to collect and transport this valuable cargo has the same goal every night: to gather the material and get it safely back to one of Quest’s labs by 2am. That way, the lab results for the person from whom the specimen comes are available by 8am a day or two later.