Clostridium Difficile Infection Calculator

Stratifies the rate of Clostridium Difficile Infection (CDI) recurrence with patient age, severity of the disease and antibiotic use.

Below the tool, there is in depth information on the major risk factors and symptoms of this infectious disease.

The Clostridium Difficile Infection calculator uses patient data referring to patient age (where the higher, the increased likelihood), severity of the infection and non-CDI antibiotic therapy in order to determine how likely it is for the CDI to recur.

The patient is then put in a risk group in order to facilitate monitoring of selected cases.

The presence of each of the three items is counted as 1 point from the final score of maximum 3 points.

There are two risk groups, low and high, each with 2 recurrence rates.

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


Age greater than 65


Severe or fulminant illness


Any non-CDI antibiotics used

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Steps on how to print your input & results:

1. Fill in the calculator/tool with your values and/or your answer choices and press Calculate.

2. Then you can click on the Print button to open a PDF in a separate window with the inputs and results. You can further save the PDF or print it.

Please note that once you have closed the PDF you need to click on the Calculate button before you try opening it again, otherwise the input and/or results may not appear in the pdf.


Clostridium Difficile Infection screening method

This Clostridium Difficile Infection screening method is aimed at grouping patients in low and respectively high risk groups, based on the possibility of suffering from recurring CDI.

CDI is said to cause between 15% and 25% of all cases of diarrhea associated with antibiotic use, especially in the cases of hospitalized patients.

The Clostridium Difficile Infection consists of the following three items:

■ Age: that can be either greater or equal to and lower than 65. Elderly patients are considered to have an increased recurrence risk, especially when hospitalized.

■ Severe or fulminant illness: where CDI is assessed based on symptoms, from mild diarrhea to pseudomembranous colitis.

■ Any non-CDI antibiotics used: whether the patient has undergone antibiotic therapy.


Result interpretation

The presence of each of the three items is counted as 1 point from the final score of maximum 3 points. According to the result, patients are allocated to a low and a high risk group. The highest possible recurrence rate is of 87.5%.

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

CDI clinical presentation and diagnosis

The major risk factors of CDI are considered to be antibiotic exposure (especially combination antibiotic therapy and long term exposure), advanced age and hospitalization.

From antibiotics, some are considered to carry a relatively higher risk, such as clindamycin, fluoroquinolones and cephalosporins. High incidence is also associated with antagonistic or pump inhibition medication.

Clinical presentation includes in most cases, diarrhea, the severity of which can range from mild to fulminant pseudomembranous colitis (PMC). Other symptoms of this infection are abdominal cramps (localized in lower quadrants), fever, high blood cell count (WBC range 50,000 cells/mm3) and presence of hypoalbuminemia due to large protein loss.

The diagnosis is confirmed either by positive culture of CD toxin in stool or enzyme immunoassay (the most common method). Severe disease can progress into paralytic ileus and subsequently, toxic megacolon.

The most common antibiotic treatment for CDI is: metronidazole, vancomycin or fidaxomicin.

The limitation of antibiotic use, prescription of probiotics and proper sanitization are amongst the main prophylaxis methods.



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

2. Henrich TJ, Krakower D, Bitton A, Yokoe DS. Clinical Risk Factors for Severe Clostridium difficile–associated Disease. Emerg Infect Dis. 2009; 15(3): 415–422.

3. Luciano JA, Zuckerbraun BS. Clostridium difficile infection: prevention, treatment, and surgical management. Surg Clin North Am. 2014; 94(6):1335-49.

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

Specialty: Infectious Disease

System: Digestive

Objective: Risk Stratification

Type: Calculator

No. Of Items: 3

Abbreviation: CDI

Article By: Denise Nedea

Published On: March 16, 2017

Last Checked: March 16, 2017

Next Review: March 10, 2023