Patients, every time they go to a hospital, will be screened for "silent killer" blood clots after the Chief Medical Officer, Prof Sir Liam Donaldson declared cutting the number of deaths from the condition as a "priority".

New guidance from the National Institute for Health and Clinical Excellence (NICE) suggests that doctors or nurses should check for the risk of a clot in every patient. This is going to become obligatory from April this year. These clots kill 25000 people every year but this measure can reduce 10,000 out of it.

Professor Beverley Hunt, from thrombosis charity Lifeblood, said, "The measures are cost-effective and have been proven to reduce hospital mortality significantly".

The guidelines also say that the patients who are dehydrated, over 60 and pregnant women are at increased risk. There is a possibility that patient suffers internal bleeding because of clots.

Pain or swelling in the leg, large veins near the surface of the skin or discolored skin on the legs are its symptoms. As preventive measures, compression stockings and blood-thinning drugs such as heparin are recommended to be given. Clots that occur in veins, most commonly in the leg, called deep vein thrombosis are being focused.