This Clostridium Difficile Infection calculator determines the CDI rate of recurrence and the risk group based on patient age, disease severity and antibiotic use. There is in depth information on how the calculator works below the form.


Age greater than 65


Severe or fulminant illness


Any non-CDI antibiotics used

How does this Clostridium Difficile Infection calculator work?

This health tool provides information on the recurrence rate and risk group for patients diagnosed with the bacterial Clostridium Difficile Infection. This condition is the most common cause of infectious diarrhea and colitis.

There are three criteria in the Clostridium Difficile Infection calculator:

■ Age greater than 65 – CDI is known to be of higher threat to elderly patients in health care facilities, especially those in long term hospitalization.

■ Severe or fulminant illness – the severity of CDI ranges from mild to fulminant pseudomembranous colitis. The greater the severity, the higher the risk group in which the patient is and the rate of recurrence.

■ Any non-CDI antibiotics used – this item refers to the fact that non-CDI antibiotics can be used as diagnosis criteria.

The presence of either of the above criteria means the score is added 1 point, therefore the final scores range between 0 and 3. The below table presents each score with their respective risk group and recurrence rate in percentage.

CDI score Risk group Recurrence rate
0 Low 0%
1 Low 33.3%
2 High 71.4%
3 High 87.5%

Clostridium Difficile Infection medical guidelines

This nosocomial and community-acquired pathogen occurs in 1/5 cases with antibiotic associated diarrhea. Given that new strains appear with antibiotic developments, in the past two decades, incidence has increased dramatically.

High incidence is also associated with the use of medication that suppresses gastric acid production, either by antagonization or pump inhibition.

Presentation is usually symptomatic with the following: watery diarrhea, fever, abdominal pain and nausea. However, the array of cases is between asymptomatic colonization and fulminant colitis which can complicate to toxic megacolon or perforation of the colon.

Main diagnosis method is the enzyme immunoassays for detection of the C. difficile toxin but stool culture (stool leukocyte and lactoferrin) is also practiced but with limited accuracy.

There is also a clinical prediction rule with the following four characteristics:

■ New onset of partially formed or watery stools (more than 3 in 24h);

Recent antibiotic exposure;

■ Abdominal pain;

■ Fever (up to 40.5 °C or 105 °F).

Antibiotic treatment for Clostridium Difficile Infection usually revolves around metronidazole, vancomycin or fidaxomicin. Oral rehydration therapy is also required. Severe cases may require colectomy.

Average recurrence rate is reported around 25%, but as revealed in the results above, it increases with the presence of certain severity factors. After the first recurrence after treatment, rates go up with every subsequent episode.

Prophylaxis methods focus on limitation of antibiotic use, probiotic use, hand washing and proper room cleaning in health facilities.


1) Burnham CA, Carroll KC. (2013) Diagnosis of Clostridium difficile infection: an ongoing conundrum for clinicians and for clinical laboratories. Clin Microbiol Rev; 26(3):604-30.

2) Bartlett JG, Gerding DN. (2008) Clinical Recognition and Diagnosis of Clostridium difficile Infection. Clin Infect Dis. 46 (Supplement 1): S12-S18.

3) Heinlen L, Ballard JD. (2010) Clostridium difficile Infection. Am J Med Sci; 340(3): 247–252.

4) Fred C. Tenover FC, Baron EJ, Peterson LR, Persing DH. (2011) Laboratory Diagnosis of Clostridium difficile Infection. Can Molecular Amplification Methods Move Us Out of Uncertainty? J Mol Diagn; 13(6): 573–582.

19 Sep, 2016