The number of hospital trusts assessing patients for deadly blood clots has more than doubled in the past year - but trusts must do more to protect patients, MPs are warning.

The all-party parliamentary thrombosis group revealed today that 70 per cent of hospitals are now risk assessing all patients for venous thromboembolism in line with recommendations from chief medical officer Sir Liam Donaldson, published last year.

When MPs surveyed trusts on take-up of the guidance a year ago, two-thirds of hospitals were failing to do the checks. And only 29 per cent of trusts responding to an HSJ survey in May on the anniversary of the guidance's publication were carrying out checks for all inpatients.

All-party group chair John Smith (Lab) told HSJ the results showed a "dramatic improvement" but added he would be personally challenging the chief executives of trusts that had not responded to the survey or were not doing the checks.

He also said he was disappointed that only 24 per cent of trusts were offering patients information on the risks of hospital-acquired deep vein thrombosis when they entered hospital.

"We think it's a patient awareness issue," he said. "As with many campaigns, patients are our biggest ally in this."

Professor Beverley Hunt, medical director of thrombosis charity Lifeblood, said: "The total costs of managing deep vein thrombosis within the NHS are estimated to be£640m, so it not only makes good clinical sense to prevent patients suffering from hospital-acquired DVT but the NHS could save a lot of money in the process by avoiding patient complications."

Health ministers have not ruled out the possibility of making the checks mandatory.

Hospital-acquired deep vein thrombosis causes 25,000 deaths a year.