Thousands of patients are failing to be assessed for their risk of developing thrombosis on admission to Epsom and St Helier University Hospitals.

Between October and December 2010, 19,839 patients were admitted to the hospitals. Of those just 3,823 patients were assessed for their risk of developing blood clots, which is the UK’s number one hospital killer.

Last year, in an effort to combat thrombosis, the Government introduced new rules requiring all Hospital Trusts to risk assess a minimum of 90 percent of in-patients.

Analysis of figures published by the Department of Health found that Epsom and St Helier Trust Hospitals are one of the bottom Trusts in the country, with just 19.3 percent of patients being assessed on their admittance.

The trust is also one of five in the country, yet to achieve the national average of 68 percent for thrombosis risk assessment.

Dr Simon Noble, Medical Director of the Thrombosis Charity Lifeblood, said the trusts have a long way to go before they meet the Government’s expectations.

He said: “The figures in Greater London are not encouraging. Around the country hospitals are making real progress and beginning to meet national thrombosis risk-assessment targets but these Hospital Trusts still have a long way to go to make sure patients are provided with the minimum expected standards of thrombosis risk-assessment.”

A spokesman for Epsom and St Helier Trust said: “As a trust we are committed to continuously improving the quality and safety of the care we provide and recognise the absolute importance of assessing our patients for potential blood clots (thrombosis).

“Over the last year, we have put in place a number of high-profile measures to make sure patients are assessed.

"Importantly, these measures, combined with other initiatives currently being implemented, are already paying dividends with our assessment rates doubling in recent months.”