The use of what is known as the oral glucose stress test was found to pick up three times as many cases of pre-diabetes than the fasting plasma glucose test.
The test involves taking a blood sample from a patient after fasting, and two hours later after drinking a sugary solution.
The study, involving 172 obese children aged five to 17, compared the glucose stress test against the fasting plasma glucose test.
Using the stress test, the researchers identified that 25 per cent of the children met the diagnostic criteria for pre-diabetes and metabolic syndrome. But when they relied on the results of the fasting blood glucose test they found that only 8 per cent of the children met the criteria for pre-diabetes or metabolic syndrome.