An investigation has revealed that thousands of people could be misdiagnosed by NHS doctors every year

Doctors could be making a wrong diagnosis in as many as one in six patient consultations in hospitals and primary care, according to the investigation that was released this month.

Between April 2008 and March 2009 there were 39,500 reports of incidents involving clinical assessment.

However, these numbers are not the only troubling implication of the research.  Most cases of misdiagnosis are not recorded anywhere in the NHS and we can only make an estimate as to the actual number of cases.  This has led to growing demands for better reporting systems.

The National Patient Safety Agency (NPSA) runs a database that records medical errors, patient incidents, mistakes in medical notes and near-misses on a voluntary basis.

Patient charity Action Against Medical Accidents (AAMA) has called for a change in the law to make reporting of misdiagnoses a mandatory requirement of doctors. 

AAMA chief executive Peter Walsh said: 'We have 4,000 inquiries a year and of those in primary care a large proportion, perhaps about 50 per cent of cases, involve misdiagnosis of some sort. 

Mr. Walsh added the AAMA supports legislation of the matter.  He believes reporting misdiagnosis should be a legal requirement, in order to achieve a more reliable picture of the reality.  In addition, if misdiagnosed cases are to be reported and analysed, it may cause a decrease in cases.

A review published recently in the American Journal of Medicine, about misdiagnosis in developed countries, suggested that up to 15 per cent of all cases could be misdiagnosed.  

Earlier this year a Westminster parliament health committee report identified that: 'Delayed or missed diagnosis in general practice is a significant problem, generating many complaints and claims.'  

Separate research suggested that one in 10 patients in hospital suffered harm because of the care they received.