People recovering from surgery get infections far more often than is being reported, according to a university-led study.

Infection prevention specialists are now calling on the Department of Health to bring in a standardised system for hospitals to try to identify the true scale of surgical infections.

They say the study, carried out by De Montfort University, has shown “worrying inconsistencies” between hospitals in how surgical site infections were defined and how rigorously they looked for them.

It is now feared that published infection rates for hospitals do not always give a true picture.

The paper, published in the Journal of Hospital Infection, casts further doubt on the reliability of the national surgical site infection surveillance scheme in England.

Professor Judith Tanner, lead researcher, said: “The national SSI surveillance system in England consistently under-reports the true scale of surgical infection and gives a false sense of security.

“This study shows there are so many inconsistencies that it’s not possible to benchmark hospitals against the English national surgical site infection data.”

Specialists at De Montfort University, Leicester, Southport and Newcastle universities, sent out a questionnaire to all 156 NHS hospital trusts in England asking how they collected and reported data on post-operative wound infection for the national SSI surveillance scheme.

The results showed what the researchers describe as “worrying inconsistencies” between hospitals.

Trusts that actively extended their surveillance to patients who had had knee replacement, after they had been discharged from hospital, reported an infection rate of 4.1 per cent, while hospitals that did not look so hard reported a lower rate of 1.5 per cent.

The authors suggested that in order to identify the true scale of surgical infections, hospitals should contact every single patient, by letter or phone within 30 days after surgery.

Prof Tanner added: “The harder you look, the more that you find.

“Common sense tells you this and now we have demonstrated that with this study.

“Perversely, hospitals that conduct robust and high quality surveillance are penalised under the current system.”