"The implications of these delays are huge for the individual and for the community. The patient is waiting for treatment, and in the meantime they could be passing on a very contagious disease," New Scientist magazine quoted project leader Barry Mendelow as saying.
The uncrewed aerial vehicles (UAVs) are designed to be launched from clinics and pilot themselves along a pre-programmed route to the nearest lab, using GPS and microelectronic gyroscopes to guide them. They drop their cargo at a predetermined spot, or on directions from the ground, and return along their flight path.
The robot planes can land automatically, or under remote control by staff.
Mendelow's team has successfully test-flown two different UAVs during the pilot project, and both of them could launch, fly and drop dummy samples in wind speeds of up to 45 kilometres per hour.
The planes are so small that they pose little danger to people on landing or takeoff.
They can carry over small, dry and light sputum samples stored on blotting paper that are used by newer DNA-based tests.
Since the samples are also sterilised, there is no risk of live bacteria or viruses escaping in the event of a crash landing.
Patients will not have to wait for a UAV to return because lab results can be sent to remote clinics by cellphone text message.
The aircraft should allow patients to get results within a day of providing a sample, says Mendelow.
"It's a very exciting idea. We need to know if it's reliable enough from a technological point of view," she adds, "but we will only find out by trying," says Ruth McNerney of the London School of Hygiene and Tropical Medicine in the UK, who researches TB in Africa.
The team are waiting for authorisation from the South African Civil Aviation Authority to begin trials transporting samples from a real clinic.