Positive predictive value of the immunoassay for Clostridium difficile toxin A and B detection at a private hospital.
BACKGROUND
Clostridium difficile (C. difficile) is a Gram-positive bacillus that is a common cause of diarrhea in the hospital environment, with a documented incidence of up to 10%. There are different methods to detect it, but a widely used test in our environment is the immunoassay for toxins A and B.


OBJECTIVE
The aim of our study was to 1) estimate the positive predictive value of the immunoassay for the detection of the C. difficile toxins A and B, 2) to establish the incidence of C. difficile-associated diarrhea in the hospital, and 3) to know the most common associated factors.


METHODS
A diagnostic test accuracy study was conducted within the time frame of January 2010 to August 2013 at the Hospital Christus Muguerza® Alta Especialidad on patients with symptoms suggestive of C. difficile-associated diarrhea that had a positive immunoassay test and confirmation of C. difficile through colon biopsy and stool culture.


RESULTS
The immunoassay for toxins A and B was performed in 360 patients. Fifty-five of the cases had positive results, 35 of which showed the presence of C. difficile. Incidence was 10.2% and the positive predictive value of the test for C. difficile toxins A and B was 0.64 (95% CI, 0.51-0.76). Previous antibiotic therapy (n=29) and proton pump inhibitor use (n=19) were the most common associated factors.


CONCLUSIONS
C. difficile incidence in our environment is similar to that found in the literature reviewed, but the positive predictive value of the test for toxin A and B detection was low.
Medicina Interna, Hospital Christus Muguerza Alta Especialidad/UDEM, Monterrey, Nuevo León, México. Electronic address: silvia_pt_72@hotmail.com.
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Pérez-Topete
Medicina Interna, Hospital Christus Muguerza Alta Especialidad/UDEM, Monterrey, Nuevo León, México.
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Miranda-Aquino
Departamento de Educación e Investigación de Salud, Hospital Christus Muguerza Alta Especialidad/UDEM, Monterrey, Nuevo León, México.
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Hernández-Portales
D000328:Adult; D000368:Aged; D001426:Bacterial Proteins / Q000032:analysis*; D001427:Bacterial Toxins / Q000032:analysis*; D016360:Clostridioides difficile / Q000737:chemistry*; D003967:Diarrhea / Q000209:etiology; D004761:Enterocolitis, Pseudomembranous / Q000175:diagnosis*; D004768:Enterotoxins / Q000032:analysis*; D005260:Female; D016304:Hospitals, Private; D006801:Humans; D007118:Immunoassay / Q000379:methods; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D015203:Reproducibility of Results
D001426:Bacterial Proteins; D001427:Bacterial Toxins; D004768:Enterotoxins; C041348:tcdA protein, Clostridium difficile; C031815:toxB protein, Clostridium difficile
Antibiotic-associated diarrhea; Clostridium difficile; Cultivo; Culture; Diarrea asociada a antibióticos; Positive predictive value; Prueba de inmunoanálisis para detección de toxinas A y B; Toxin A and B detection immunoassay; Valor predictivo positivo