Experts have urged GPs to review their QOF registers after guidance suggested that up to 30 per cent of epilepsy patients may be misdiagnosed.

The estimate of misdiagnosis emerged from a NICE draft guideline on Transient Loss of Consciousness (TLoC), or 'blackout'.

Experts believe that many patients diagnosed as having epilepsy could in fact suffer from syncope.

The syncope charity STARS believes that between 30-40 per cent of patients diagnosed with epilepsy might fall into this category.

In 2007, the All-Party Parliamentary Group on Epilepsy reported that there were at least 74,000 patients with a misdiagnosis of epilepsy in England alone.

Syncope is one cause of TLoC, but epilepsy and psychogenic blackouts are also key causes.

Dr Matt Fay, a GP from Shipley, West Yorkshire, who has a special interest in cardiology said: 'I personally feel it is beholden on any GP to question the previous opinion of "experts". All patients with a diagnosis of epilepsy who join my practice have a 12 lead ECG performed.'

He emphasised that misdiagnosis is generally not a case of medical negligence but a series of confounding errors.

Patients may then receive various unpleasant medications while the underlying cause remains unrecognised and untreated.

'Unfortunately epilepsy, like syncope, has no signs in between events. It often takes another set of eyes, starting from scratch, to identify the glitches in the diagnosis,' Dr Fay added.

Dr Adam Fitzpatrick, con-sultant cardiologist at the Manchester Heart Clinic and chairman of the STARS medical advisory committee, said that convulsive syncope could resemble epilepsy, causing misdiagnosis.

He called for the addition of an extra category in the NICE draft guideline for convulsive syncope.

The NICE draft guideline, which is out for consultation until 17 March, covers the initial management of people who have experienced TLoC within any NHS care setting in England and Wales.