Thousands of medical and dental students could be sitting a new university entrance exam as early as next summer.
The admissions test - the UKCAT - was set up by a consortium of more than 20 medical schools. It is designed to test the academic potential of students and to boost the numbers of students from working-class backgrounds entering medicine.
The examination will be an alternative to the Biomedical Admissions Test (Bmat), used by medical schools at Cambridge, Oxford and Manchester universities and Imperial College London and University College London.
Unlike the Bmat, which tests students on their scientific knowledge and includes an essay section, the UKCAT will focus on problem-solving abilities and communication skills.
The chairman of the UKCAT consortium, Ian Johnson of Nottingham University, said: "A-level grades are good as indicators of academic performance; but as a larger and larger percentage of students get A grades, they become a blunt tool. They no longer discriminate academic success adequately."
He said that the medical schools had acted together to prevent a proliferation of tests.
The announcement comes just as 50,000 A-level students are sitting the US-style SAT as part of a £1.6 million longitudinal study to assess its suitability as a university entrance exam for the UK.
Sir Peter Lampl, chairman of the Sutton Trust and a member of last year's Schwartz committee on admissions, which warned against a mushrooming of such tests, was supportive of the move. He said: "I have always accepted the fact that there is a case for medical schools having their own aptitude test, and it is good that so many have got together to devise a uniform one."
Professor Johnson said that students would sit the test at the same time as their AS levels in 2006 and would receive the results well before applying to medical schools for 2007 entry.
"We believe this will help with the introduction of post-qualifications admissions systems, allowing students to make far more informed choices about where and what to study," he said.
Results will be fed into a database that will monitor students over the coming years.
The consortium is due to make an announcement shortly on which company will run the tests. Students are expected to be able to sit them in a range of centres throughout the UK and overseas. The test will cost about £50 to sit, and the consortium is planning a bursary scheme to help poor students with the cost.