Concerns over discrimination in the UK general practitioner examination are raised in a study published on bmj.com.

The researchers say they cannot rule out "subjective bias owing to racial discrimination" in the exam and call for additional training for international medical graduates to help them adapt to the UK health care system.

A BMJ Careers investigation also reveals that ethnic minority doctors are less successful in securing NHS hospital posts than white doctors.

In order to practise as an accredited general practitioner (family physician) in the UK, doctors must pass the MRCGP (Membership of the Royal College of General Practitioners) examination.

But concerns have been raised about the high failure rate of ethnic minority candidates. And it has been questioned whether the clinical skills assessment part of the exam discriminates against these individuals.

With continuing dependence on international medical graduates in meeting the workforce needs of many developed countries, including the UK, understanding the barriers that these doctors face in entering and completing specialist medical training is important.

So researchers at the University of Manchester analysed data for 5,095 candidates sitting the applied knowledge test and clinical skills assessment components of the MRCGP examination between 2010 and 2012 - to determine the difference in failure rates by ethnic or national background.

A further analysis was carried out on 1,175 candidates not trained in the UK, who sat an English language capability test (IELTS) and the Professional and Linguistic Assessment Board (PLAB) examination, as required for full medical registration.

The data was provided by the Royal College of General Practitioners and the General Medical Council.

After controlling for age, sex, and performance in the applied knowledge test, significant differences persisted between white UK graduates and other candidates.

British black and minority ethnic graduates were more likely to fail the clinical skills assessment at their first attempt than their white UK colleagues (17% v 4.5%). Black and minority ethnic candidates who trained abroad were also more likely to fail the clinical skills assessment than their white UK colleagues (65% v 4.5%).

For candidates not trained in the UK, black or minority ethnic candidates were more likely to fail than white candidates, but this difference was no longer significant after controlling for scores in the applied knowledge test, IELTS, and PLAB examinations.

The authors say they "cannot exclude subjective bias owing to racial discrimination in the marking of the clinical skills assessment as a reason for these differential outcomes."

They say previous training experience and cultural factors could help explain these differences, but point out that they "cannot explain differences between white candidates and black and minority ethnic candidates who have trained in the UK, and who would have had similar training experiences and language proficiency."

They suggest that changes to the clinical skills assessment "could improve the perception of the examination as being biased against black and minority ethnic candidates" and recommend additional training for international medical graduates "to enable their adaption to the UK health care system."

An investigation by BMJ Careers has found that white doctors are almost three times more likely to land senior hospital jobs than ethnic minority doctors (13.8% v 4.8%).

The figures, based on 2012 ethnicity data from 50 hospital trusts in England, show that Black or Black British applicants were the ethnic group least likely to secure hospital doctor jobs (2.7% success rate), followed by doctors of mixed ethnicity (3.5%), and Asian and Asian British doctors (5.7%).

Interestingly, doctors who did not disclose their ethnicity during the application process had the highest success rate in landing jobs of any ethnic group (23%) - further muddying the waters around potential discrimination in the appointment of NHS doctors.

The British International Doctors Association said these data "add weight to the possibility that the NHS is discriminatory in how it appoints doctors to posts." while the British Medical Association said the findings were "concerning as any form of discrimination is unacceptable in today's NHS."

BMJ Careers Editor, Tom Moberly says: "The factors behind ethnic minority applicants' lower success rates in applications for NHS roles are complex. Direct discrimination on the basis of ethnicity would not explain the findings since differences are evident at the shortlisting stage, when information on ethnicity is not available. Also, the group of doctors most likely to be successful when applying for an NHS position are those who do not disclose their ethnicity.

But explanations of how doctors from ethnic minority groups may be disadvantaged when they apply for NHS jobs can only be considered in detail if data are brought out in the open and discussed."