While some universities welcome admissions tests, others fear they will exclude students from poor backgrounds.
Five years ago, Cambridge University enlisted local expertise to devise a test to help distinguish between the 1,000-plus qualified applicants competing for fewer than 300 medical places.
It turned to the University of Cambridge Local Examinations Syndicate, a non-teaching department of the university, which had carried out substantial research into thinking skills, the ability to think critically and solve problems.
The syndicate devised the Medical and Veterinary Admissions Test (Mvat).
This has now evolved into the BioMedical Admissions Test (Bmat) used last year by Oxford, Cambridge and University College London medical schools.
Geoff Parks, director of admissions for the Cambridge colleges, said that research on the two Cambridge cohorts who sat the Mvat is at an early stage. But initial studies showed that pupils' performance was not linked to the type of school they attended.
And, while the majority of medical applicants have three A levels at grade A or two As and a B, the results of last November's first Bmat show an unmistakable bell curve on a scale running from zero to nine.
The Bmat has been designed so that typical students applying to the most highly selective undergraduate university courses in the UK will score about 5.0. The best applicants will get higher scores, but only a few exceptional applicants are expected to achieve a score of more than seven.
The candidates who sat the Bmat have not yet had their A-level results, but Dr Parks said: "The Mvat, and now Bmat, differentiates between applicants who, on paper, are almost indistinguishable on the basis of their GCSE performance and predicted A-level results.
"There is a positive correlation between performance in the Mvat and subsequent performance on the medical course at Cambridge.
"This correlation is as good as or better than for any other single indicator we use in admissions, so the Mvat/Bmat is contributing helpful additional information to the selection process."
The Bmat test has three sections. The first addresses thinking skills and assesses how well candidates deal with problem-solving, understanding arguments, data analysis and inference.
The Bmat website urges candidates to practise the specimen questions it provides, but it warns: "What you cannot do is to be taught to answer as if you were a performing seal."
The second section tests core knowledge of science and mathematics and how to apply this, while the third section is an essay on a statement such as "a little learning is a dangerous thing" or "it is ridiculous to treat the living body as a mechanism".
This year, Bristol University's Veterinary School and the Royal Veterinary College signed up to use the test, which all applicants will sit on November 3.
The registration website (www.bmat.org.uk/) is expected to go live this weekend. Candidates have until September 30 to register. The fee to sit the test is £15 for UK students, but this may be reimbursed in cases of hardship.