A husband-wife team of doctors-Jan Knight and Robert Knight-is using this test to tell Olympic coaches whether sportspersons are ill or stressed, as they prepare for Beijing.
The couple, who farm the piddocks in Pymouth, have revealed that their ingenious approach is all about detecting white cell activity in blood using a painless pinprick test.
According to them, when a competitor complains of feeling under the weather, it means coaches and doctors can tell whether an elite athlete is exercising too hard or about to be struck down, and accordingly prescribe medicines and rest.
The doctor couple says that coaches may also quarantine a sickly person at an early stage to prevent them from infecting the rest of the squad.
They believe that their test may find broader uses, for instance in the workplace where it may help a boss know when a key worker is below par and likely to come down with a cold, and to monitor the progress of an infection.
Jan and Robert have revealed that their test is inspired by an exquisitely sensitive chemical reaction found in the common piddock.
The creature is bioluminescent, meaning that it can give off a green-blue light when a protein called Pholasin encounters highly reactive chemicals called free radicals that are also produced by white blood cells that protect the body.
"When white cells in the body get 'angry' because of disease, they produce chemical substances which kill bacteria, but also 'turn on' the glow of Pholasin," the Telegraph quoted Dr. Robert Knight as saying.
He said that working with his wife in their Knight Scientific lab, he developed a product from the protein, and a method whereby it could be mixed with blood and the activity of white cells measured by how much light is given off.
"We can tell if people are training too hard, because their white cells get hectic. We can also see the beginnings of infection, so a physician can prescribe drugs early on," said Dr. Robert Knight
"When you think of the immense amount of money it costs to take a team to China, it's important they are at their peak at the right time," he said.
Dr. Jan Knight added: "We can detect changes in the body before they get symptoms. White cells know you are ill before you do. Our test gets white cells to divulge their secrets."
The sailing team has been given, and trained to use a special kit that produces a drop of blood from a pinprick.
The team can now test its competitors in China, and send the results by email to Plymouth for comment.
Costs depend on the numbers, falling to around 15 pounds in some applications.