Conventional testing is carried out in the laboratory

The test, which provides results within an hour, checks for a protein in urine which indicates there is a tumour.

Currently, doctors rely on laboratory tests to detect tumours - but results can take days to come through.

University of Texas researchers told the Journal of the American Medical Association the test could save lives, after they tried it on 1,331 people.

And a Cancer Research UK spokesman said the test was a "significant advance".

This is a test which can be readily applied at the point of care in the doctors office and is cheap to perform Professor Gareth Williams, University College London

Around 10,700 cases of bladder cancer are diagnosed in the UK each year. Two thirds of those affected are over 70.

In 2002, 4,910 people died from the cancer.

'Gold standard'

The Texas researchers recruited 1,331 patients suspected of having bladder cancer because of risk factors such as blood in their urine, or a history of smoking.

A sample of urine was collected from each patient. Half was used to test for the NMP22 protein, which indicates there is a tumour.

The rest was used for a conventional cytology test - a lab test which looks for abnormal cells in the urine.

The patients also received a cystoscopy, the "gold standard" test which involves inserting a tube containing optic fibres into the bladder to allow the doctor to check for abnormalities.

However, there is concern that the visual nature of the test means bleeding or inflammation can mean some tumours are masked and can be missed, and that therefore other tests are also needed.

The researchers found that combining cystoscopy with the NMP22 test detected 93.7% of cancers, compared with 88.6% with an initial cystoscopy alone.

Repeated cystoscopies detected the other cancers - with a total of 79 people eventually being diagnosed with bladder tumours.

In total, the NMP22 test detected cancer in 44 (55%) of the 79, compared to cytology - currently used as the 'second check', which detected cancer in 12 patients out of 76 tested (16%).

However, more false positives - where a test indicates cancer which is not there - were seen with the NMP22 test, compared to cytology.

'Exciting advance'

Barton Grossman, who led the research, said: "This test is easy and may save lives."

But he said the NMP22 test should not be used on its own, and should be combined with cystoscopy to provide an accurate diagnosis.

"No single procedure is 100% sensitive, so a combination of procedures is recommended."

Professor Gareth Williams, Cancer Research UK Senior Clinical Research Fellow at University College London, said: "The non-invasive NMP22 test is a significant advance over urine cytology with respect to its sensitivity and therefore offers the hope of early cancer detection and therefore saving lives.

"Moreover this is a test which can be readily applied at the point of care in the doctors office and is cheap to perform."

He added: "Urine cytology requires the support of pathology laboratories, skilled laboratory technicians and cytopathologists which means results take longer and tests are more expensive to perform.

"Although this is an exciting advance, this non-invasive test is still constrained by its relatively low sensitivity in which 45% of cases are missed and therefore further research is still urgently required to identify better cancer markers."