The checklist is five things that doctors need to do when inserting central intravenous lines to avoid subsequent infection: wash hands with soap; clean the patient’s skin with chlorhexidine antiseptic; cover the patient’s entire body with sterile drapes; wear a mask, hat, sterile gown and gloves; and put a sterile dressing over the insertion site after the line was in. 

In an experiment where nurses were strict in enforcing the checklist, and doctors toed the line, the central line infection rate in the John Hopkins Medical Centre I.C.U. dropped from 11 percent to zero in one year.