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Frequently Asked Questions
C. Data queries
Case Entry
CE - FAQ0016

Q: What is the case definition of CDI used for reporting cases onto the DCS?

A: The protocol outlines the case definitions for CDI and MRSA bacteraemia. In summary the case definition for CDI is as follows: Professor Brian Duerden, An Inspector Calls, British Infection Society/Association of Medical Microbiologists newsletter, March 2010 '...reporting of cases in the mandatory surveillance system should be based upon the diagnosis made according to the algorithm used; if the patient has been diagnosed as a case of CDI according to the diagnostic system used, then it should be reported as a positive case.' In addition, the following case definitions apply:
  • All cases of infection caused by C. difficile in patients 2 years of age and older.
  • Cases in patients aged under 2 years need not be reported; however, Trusts may use the system to record these cases if they so wish. These will be excluded from data for publication.
  • All cases should be reported regardless of location of the patient at the time the specimen was taken i.e. regardless of whether the patient was in a hospital or another setting.
  • Positive specimens taken within 28 days of the first specimen should not be reported as they are considered to be the same episode, unless a negative result has been obtained between the two positive results. Positive specimens taken more than 28 days after the first sample of each episode should be reported as these are considered to be part of a new episode.
The surveillance system assumes the following:
  • Only stools from symptomatic patients are tested, i.e. only liquid/loose stools that take the shape of the container (Bristol Stool Chart types 5–7) should be examined. In suspected cases of ‘silent’ CDI, such as ileus, toxic megacolon or pseudomembranous colitis without diarrhoea, other diagnostic procedures, such as colonoscopy, white cell count (WCC), serum creatinine and abdominal CT (computerised tomography) scanning, may be required. Non-diarrhoeal stools should not be tested[r2] .
  • That all individuals aged 65 years or more with diarrhoeal symptoms will be tested for C. difficile and those aged under 65 years will be tested based on clinical indication such as the “typical” C. difficile smell, recent exposure to antibiotics or proton pump inhibitors, contact with healthcare settings, or treatment of the GI tract.