Patients are being kept in the dark about the danger of hospital-acquired blood clots, it has been claimed.
Half the former surgical patients questioned for a UK-wide survey said no-one discussed the risk of blood clots with them in hospital.
Yet blood clots are the biggest cause of hospital deaths in the UK, accounting for an estimated 25,000 fatalities each year.
Professor Beverly Hunt, medical director of Lifeblood: The Thrombosis Charity, said: "This is a widespread, life-threatening problem - both healthcare professionals and the public have a part to play to ensure that this leading cause of death is prevented as much as possible.
"The research clearly shows that there is a huge education gap concerning hospital acquired blood clots. We call for patients to engage in discussion with healthcare professionals and visit the Lifeblood website without further delay to ensure they are fully informed about the risks involved."
A total of 1,000 people took part in the poll including 758 who had stayed overnight in hospital to undergo surgery.
The survey showed that the MRSA superbug, hospital food, and noisy wards were greater causes of concern than blood clots. Previous research has shown that clots kill 20 times more patients than MRSA and claim more lives in hospital than breast cancer, Aids and traffic accidents combined.
Guidelines within the NHS Commissioning Framework say that 90% of all adult patients should be assessed for their risk of clots on admission to hospital.
Hospital-acquired blood clots include deep vein thrombosis (DVT) in the legs and pulmonary embolism, a potentially fatal clot in the lungs.
The survey was commissioned by the pharmaceutical company Boehringer Ingelheim (UK) Ltd and published by Lifeblood: The Thrombosis Charity. It was conducted by independent researchers Eggington Research Associates.