If Naomi Gadian wins her case all medical schools may have to revise their testing policies and it could force other professional bodies or employers to follow suit.
The student plans to take action against the General Medical Council (GMC) and her college under the Disability Discrimination Act 1995.
Under the Act universities must make "reasonable adjustments" for students with disability who experience "substantial disadvantage" in their education.
The GMC said it has no powers to set medical examinations which are controlled by individual colleges and universities.
But Ms Gadian's argument is that the GMC is the body that sets the standards for undergraduate medical education.
"In normal life you don't get given multiple choice questions to sit. Your patients aren't going to ask you 'Here's an option and four answers. Which one is right?'" says Ms Gadian.
Miss Gadian got an A and two Bs in her A-level exams, but her solicitor John MacKenzie said she was at a disadvantage at her college because they predominantly use multiple choice for assessment.
"Naomi is very bright, very dedicated and very hard-working," he said. "She also has a form of dyslexia which means she has difficulty with multiple choice questions."
"This is not a question of a lack of intelligence or a lack of intellect. They have got to come up with a different way of testing her knowledge," MacKenzie added.
According to a spokesman from Peninsula College, a branch of the University of Exeter, several students suffering from dyslexia - which affects 10 per cent of the population - had graduated from the college.
"Our ultimate responsibility is to produce doctors of the highest quality who are fit for practice, and any reasonable adjustments we have made for students with dyslexia reflect this objective," said the spokesman.
Oxford University neuroscientist Professor John Stein, who has been studying dyslexia for 25 years, said dyslexics struggle to concentrate on multiple choice because of poor eye co-ordination.
He said: "Dyslexics confuse the order of letters because their eye control is not ideal."