tailieunhanh - Chapter 123. Clostridium difficile–Associated Disease, Including Pseudomembranous Colitis (Part 3)

Table 123-1 Relative Sensitivity and Specificity of Diagnostic Tests for Clostridium difficile–Associated Disease (CDAD) Type of Test Relative Sensitivitya Relative Specificitya Comment Stool for C. difficile culture ++++ +++ Most sensitive test; specificity is ++++ if the C. difficile isolate tests positive for toxin; with clinical data, is diagnostic of CDAD Cell culture +++ ++++ With clinical data, is diagnostic of CDAD; highly specific but not as sensitive as stool culture cytotoxin test on stool Enzyme immunoassay for +++ ++ to +++ With clinical data, is diagnostic of CDAD; rapid results, but not as sensitive as stool culture or cell culture cytotoxin test toxin A or toxins A and B in stool Latex test for C. difficile antigen in stool ++ +++ Detects glutamate dehydrogenase found in. | Chapter 123. Clostridium difficile-Associated Disease Including Pseudomembranous Colitis Part 3 Table 123-1 Relative Sensitivity and Specificity of Diagnostic Tests for Clostridium difficile-Associated Disease CDAD Type of Test Relative Relative Comment Sensitivity Specificity Stool culture Most sensitive test for C. difficile specificity is if the C. difficile isolate tests positive for toxin with clinical data is diagnostic of CD AD Cell culture cytotoxin test on stool With clinical data is diagnostic of CDAD highly specific but not as sensitive as stool culture Enzyme immunoassay for toxin A or toxins A and B in stool to With clinical data is diagnostic of CDAD rapid results but not as sensitive as stool culture or cell culture cytotoxin test Latex test for C. difficile antigen in stool Detects glutamate dehydrogenase found in toxigenic and nontoxigenic strains of C. difficile and other stool organisms less sensitive and specific than other tests rapid results Colonoscopy or sigmoidoscopy Highly specific if pseudomembranes are seen insensitive compared with other tests According to both clinical and test-based criteria. Note 90 71-90 51-70 -50 . Despite the array of tests available for C. difficile and its toxins Table 1231 no single test has high sensitivity high specificity and rapid turnaround. The turnaround time for reporting of a positive result in the cell cytotoxicity test can be shortened to 24 h if cell cultures are examined at intervals as short as 4 h. However this approach is labor intensive and observation for 48 h is required for a conclusive test result. Most laboratory tests for toxins lack sensitivity. However testing of multiple additional stool specimens is not recommended. Empirical treatment is appropriate if CDAD is strongly suspected on clinical grounds. Testing of asymptomatic patients is not recommended except for epidemiologic study purposes. In particular so-called tests of cure following treatment are .