Value of Repeat Testing for Clostridium difficile Infection (GDI) Using Enzyme Immunoassay Technique in a Large Tertiary Center

1Cleveland Clinic, Cleveland, OH
2Cleveland Clinic, Cleveland, OH
3Cleveland Clinic, Cleveland, OH
4Cleveland Clinic, Cleveland, OH
5Cleveland Clinic, Cleveland, OH
6Cleveland Clinic, Cleveland, OH
7Cleveland Clinic, Cleveland, OH

Meeting: Hospital Medicine 2010, April 8-11, Washington, D.C.

Abstract number: 108


Clostridium difficile infection (GDI) is one of the most common hospital‐acquired infections, and its prevalence and severity have been increasing. It is crucial to make a timely and accurate diagnosis so that treatment and containment strategies can be implemented appropriately. The stool enzyme immunoassay (ElA) for toxins A and B is the most commonly used laboratory test to diagnose CDI. The common diagnostic trend for suspected CDI has been to send 3 successive stool samples to increase the sensitivity of the commercially available EIA tests. The aim of the study was to determine the value of such a practice.


A retrospective cohort study was designed using a database of all stool ElAs that were performed on hospitalized patients between January 2005 and December 2008. The results of all the tests were taken into consideration for each episode of diarrhea. The data were analyzed for the test's sensitivity, specificity and negative predictive value. Transition probabilities were calculated based on repeat testing results. The Cleveland Clinic Institutional Review Board approval was obtained before data collection


There were a total of 29,373 episodes of diarrhea in 17,971 patients over a course of 3 years. Among all the subjects, a total of 2692 (9.17%; Cl 8.84%‐9.50%) were diagnosed positive for CDI, of which 2675 subjects (9.11%; Cl 8.78%–9.44%) were detected based on the first 3 tests. Two thousand four hundred and forty‐two subjects (8.31%; Cl 8.0%–8.64%) were detected on the first test itself, 179 (6.6%) in the second test, and only 54 (2%) in the third test. These data were further analyzed to look at whether repeat testing of negative EIA results yields any subsequent positive results. If the first test was negative, the probability that the second test was positive was 2.2% (Cl 1.9%–2.7%). Similarly, if the first 2 tests were both negative, the probability that the third test was positive was 2.3% (Cl 1.7%–3.1%).


Most patients with CDI were diagnosed on the first test itself (90.9%), and fewer than 9% were detected on repeat testing, This shows that the diagnostic yield of repeat stool testing is very low and emphasizes the need for shifting to newer diagnostic modalities. Per present guidelines, testing 3 stool specimens is not recommended routinely, as it is not considered cost effective. However the clinical implication of a missed diagnosis of CDI will need to be further analyzed (Gerding DN, Johnson S, Petersen LR, et al. Clostridium difficile–associated colitis and diarrhea. Infee Control Hosp Epidemiol. 1995;16:459–477).

Author Disclosure:

P. Patel, none; A. Deshpande, none; V. Pasupuleti, none; G. Goel, none; G. Hall, none; H. Bo, none; A. Jain, none.

To cite this abstract:

Patel P, Deshpande A, Pasupuleti V, Goel G, Hall G, Hu B, Jain A. Value of Repeat Testing for Clostridium difficile Infection (GDI) Using Enzyme Immunoassay Technique in a Large Tertiary Center. Abstract published at Hospital Medicine 2010, April 8-11, Washington, D.C. Abstract 108. Journal of Hospital Medicine. 2010; 5 (suppl 1). Accessed May 23, 2019.

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