|Variables||Dog response||Laboratory tests*||Diarrhoea on day of detection round||Comment|
|Inconclusive dog response:|
|Case 1||Inconclusive||Positive result||Yes||Dog appeared distracted by plastic cup on floor|
|Control 2||Inconclusive||Negative result||Yes||During this round there was a strong chlorine smell in several rooms, from disinfection, which could have influenced the dog’s response. Tests were done on participants with an inconclusive response in this round|
|Case 3||Inconclusive||Positive result||Yes||Chlorine round, see comment for control 2|
|Control 4||Inconclusive||Not done||No||Case 5 had just changed beds; the dog seemed to have difficulty choosing between two neighbouring patients (control 4 and case 5) and the third (empty) bed across the room; he sat in the middle|
|Case 5||Inconclusive||Positive result||Yes||See comment for control 4|
|Control 6||Inconclusive||Negative result||Yes||On the ward was a patient with Clostridium difficile infection who refused to participate in the study. The dog was not allowed to enter the patient’s room; however, the dog was excited and tried to enter. When forced to move away, he immediately sat down next to control 6, who was the first participant he encountered. Because of symptoms, tests had been done. The enzyme immunoassay gave a negative result; however, stool culture showed non-toxigenic C difficile|
|Control 7||Inconclusive||Negative result||Yes||No apparent explanation|
|Control 8||Positive||Negative result||No||Chlorine round, see comment for control 2. Enzyme immunoassay gave a negative result; however, stool culture showed non-toxigenic C difficile|
|Control 9||Positive||Not done||No||Participant offered the dog a cookie|
|Control 10||Positive||Not done||No||Participant beckoned the dog|
|Control 11||Positive||Negative result||No||Dog appeared distracted by urine on the floor from a broken catheter bag|
|Control 12||Positive||Negative result||No||This participant had been treated for C difficile infection, diagnosed 11 days previously. Since symptoms resolved on the day of the detection round, the patient was included as a control. However, a week after the round symptoms returned and retesting showed a relapse|
|Case 13||Negative||Positive result||Yes||No clear explanation|
|Case 14||Negative||Positive result||Yes||The enzyme immunoassay gave a positive result; culture was mistakenly not done|
*Enzyme immunoassay+toxigenic culture.
†Participants with negative laboratory results but positive dog response.
‡Participants with negative laboratory results but positive dog response.