The stiff shoulder that turned out to be Parkinson's Disease. The women told their period pains were all in the mind - but who years later discovered they had endometriosis, which rendered them infertile. Serious medical mistakes - with potentially disastrous consequences.

Of all complaints received by the Care Quality Commission in 2008, 36 per cent related to misdiagnosis or delays in diagnoses by GPs.

In one study, which looked at 1,000 claims brought against GPs, two-thirds involved a delayed or wrong diagnosis, including misdiagnosing serious conditions such as heart disease and cancer.

Katherine Murphy, director of the Patients' Association, said there is nothing worse for patients than a late or wrong diagnosis.

'When it goes wrong, the consequences are obvious, but the illness may not have been that difficult to diagnose,' she says.

'As gatekeepers to the rest of the NHS, a GP's duty to be up-to-date is absolute. The pressure on them is increasing: patients live longer and can have more done for them, but the standard consultation time is still only a few minutes.'

So, what might your doctor be missing? Here are seven conditions that are routinely misdiagnosed, and the red flag symptoms to look for.

For years, doctors have used cholesterol as the main measure of a person's heart health, but a new study suggests that testing for another substance in the blood may be just as important.

A 78-year-old man from Accrington collapsed and died from a heart attack after being taken to a cash machine by a bailiff to pay a £60 speeding fine.

Retired pub landlord Andy Miller had only been released from hospital a fortnight before following an earlier heart attack in October.

Mr Miller's family said they had told the Lancashire magistrates who ordered the bailiffs about his health problems.

Justice Minister Jack Straw has ordered an inquiry into Mr Miller's death.

The bailiff called at his house in India Street on 7 January and persuaded him to get into his car and go to Accrington town centre.

The father-of-five collapsed on his way to a cash machine while the bailiff parked and waited for the money.

In lab experiments, scientists found that the extract stimulated leukaemia cells to commit suicide.

Within 24 hours, 76% of leukaemia cells exposed to the extract were killed off, while healthy cells were unharmed, Clinical Cancer Research reports.

The study raises the possibility of new cancer treatments, but scientists said it was too early to recommend that people eat grapes to ward off cancer.

Grape seeds contain a number of antioxidants, including resveratrol, which is known to have anti-cancer properties, as well as positive effect on the heart.

Previous research has shown grapeseed extract has an effect on skin, breast, bowel, lung, stomach and prostate cancer cells in the laboratory.

It can also reduce the size of breast tumours in rats and skin tumours in mice.

However, the University of Kentucky study is the first to test its impact on a blood cancer.

Lead researcher Professor Xianglin Shi said: "These results could have implications for the incorporation of agents such as grapeseed extract into prevention or treatment of haematological (blood) malignancies and possibly other cancers.

"What everyone seeks is an agent that has an effect on cancer cells but leaves normal cells alone, and this shows that grapeseed extract fits into this category."

The researchers exposed leukaemia cells to grape extract in a range of different doses.

Many GPs, and even some hospital specialists, are failing to follow guidelines for managing heart failure, a Europe-wide survey suggests.

British GPs frequently did not use recommended tests or drugs, which there researchers said could be unsafe.

The European Heart Journal report said the results were "very worrying".

Trans fats are chemically altered vegetable oils. They are produced artificially in a process called hydrogenation which turns liquid oil into solid fat.

Trans fats can be found in thousands of processed foods from sweets and biscuits to ready meals. They are used because they are cheap, add bulk to products, have a neutral flavour and give products a long shelf life. They have no nutritional value.

Are trans fats bad for you?