Gulnar Qureshi, 44, died of two massive blood clots to the lung after she was sent home from Birmingham Heartlands Hospital twice in four weeks.

Professor Sherwood Burge, consultant chest physician at the hospital, denied gross negligence by. "There's a substantial risk of infection at Heartlands Hospital and other hospitals with MRSA," he said. "It's not a terribly safe place to be. It's usually safer at home," he told Birmingham coroner's court.

Mrs Qureshi, from Birmingham, was first admitted to the hospital after collapsing at the funeral of a nephew on 28 January, this year. She was readmitted to the hospital on 16 February, and again on 24 February, when she died. A pulmonary embolism was diagnosed on the third visit. Her family has asked why doctors discharged her twice and did not diagnose her with a pulmonary embolism until her third admission. Professor Burge told the court: "I think we have tried hard and we clearly got it wrong. It clearly had disastrous consequences." He explained that blood clots to the lungs were one of the most difficult diagnoses to make, particularly if a patient was not showing typical symptoms of the condition.

Department of Health figures published last summer showed Birmingham Heartlands and Solihull NHS Trust had the seventh worst rate of MRSA infection among general acute hospitals in England. Sub-standard cleaning practices were exposed in a BBC Panorama documentary and contract cleaners threatened to walk out last year in a row over pay discrepancies with their "in-house" counterparts. The trust has since introduced measures to help reduce its rate of MRSA infection.

Tom Parry, sister of Jane Parry who died of a brain haemorrhage after being told she was suffering from panic attacks and gall stones by doctors at Solihull Hospital and Birmingham Heartlands Hospital, said: "We were assured that the procedures for diagnosis would change after my sister's death, but it has happened again."

The coroner, Aidan Cotter, recorded a verdict of natural causes and explained to Mrs Qureshi's family that it was for a civil court to decide negligence.