Evaluation of six commercial assays for the rapid detection of Clostridium difficile toxin and/or antigen in stool specimens

Abstract

The sensitivity is much higher for Triage and the two new chromatographic assays than for the conventional EIAs. These tests also have a high negative predictive value. For Triage, C. difficile antigen-positive, toxin A-negative results can be obtained; the clinical value of these must be established by additional studies. Overall, the new-generation assays are still less sensitive than the cytotoxin assay; however, they provided same-day results, could be used as a screening test and may be useful in laboratories without tissue-culture facilities. Our results do not allow the recommendation of one single assay for the diagnosis of C. difficile-associated diarrhea. It remains the case that laboratory results must be correlated and interpreted with the clinical presentation of the patient.

Clostridium difficile-associated diarrhea in adults

“…59,60 The sensitivity of this test is 80%-90%. 61,62 Performance of the test requires a tissue culture facility, and results are usually not available for at least 48 hours. Nonspecific cytopathic effects may be ob- …”

“…60 Rapid enzyme immunoassays have been developed for the detection of toxin A or both toxins A and B from stool filtrates. [61][62][63][64] Test kits able to detect both toxins are more sensitive because they are also able to identify disease caused by toxin A-negative/toxin B-positive strains of C. difficile. One of the main advantages of these immunoassays is their rapidity, with results available within hours.…”

“…However, these tests have reduced sensitivity (65%-85%) and specificity (95%-100%) as compared with the cytotoxicity assay. 61,62 Stool culture for detection of the organism is generally less useful because of the potential for asymptomatic carriage of C. difficile strains that are nontoxigenic.…”

Evaluation of a New Commercial TaqMan PCR Assay for Direct Detection of the Clostridium difficile Toxin B Gene in Clinical Stool Specimens

“…The cell culture cytotoxicity neutralization assay (CCCNA), once considered a "gold standard," has been replaced in most laboratories by more rapid technologies. Rapid traditional methods for detection of toxins A and B, i.e., lateral flow devices and enzyme immunoassay methods, are quicker, less complex, and less expensive, but their performances differ with regard to sensitivity and specificity (1,10,12,13,(15)(16)(17)21). Although time-consuming, the most sensitive and specific method is anaerobic culture with selective media for C. difficile followed by testing of recovered isolates for cytotoxin production (1,6,12,(15)(16)(17)21).…”

Antibiotic-Associated Diarrhea and Antibiotic-Associated Colitis

“…Эти методы позволяют вы-явить токсины А и В, клостридиальную глутамат-дегидрогеназу (основной антиген микроба); они высокоспецифичны, достаточно просты в прове-дении и дают быстрый ответ. Однако чувствитель-ность ИФА и РЛА составляет всего 60-65%, а чувст-вительность ИХТ -87% [4,13]. В то же время около 34% пациентов без диареи после приема анти-биотиков имеют положительные результаты теста на цитотоксин В [7].…”