Australian researchers have developed a blood test that can predict, with 91 per cent accuracy, which influenza patients will potentially develop deadly secondary infections, such as pneumonia.

The High-risk Influenza Screen Test (HIST) measures an early warning signal released by the patient's body into their blood to kick start their immune system's fight against the infection.

The test needs only a single drop of blood and within a few hours it can predict which patients with influenza will go on to develop infections such as pneumonia. Previously doctors could only test for influenza infection but didn't know which patients would be at risk of rapid deterioration.

The study deciphered the genetic codes that immune cells release to warn the body of a serious infection, such as pneumonia, caused by the influenza virus. In addition, HIST will be useful during pandemics when there is a delay in developing vaccines for strains of the influenza virus.

The early warning can provide a greater chance to treat the patient's infection before it overwhelms them and potentially kills them.