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No test for clostridium difficle is 100% accurate, since the pathogen naturally exists
in the insestinal track. The tests must be done to detect the toxins ( A & B) that cause it to become a problem. Many
factors play a role in this and a false result is quite common. The most common tests that are done follow.
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In a laboratory test (cytotoxicity assay) the toxins can be easily observed in the microscope. This tissue culture test
is considered the gold standard because of its high sensitivity and specificity. Since there is no connection between levels
of C. difficile toxins in the stool and severity of the disease, the results are reported simply as "positive" or "negative."
However, time is a drawback of this test since it requires 24 to 48 hours to read the results
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Over the past few years several rapid tests that take just a few hours, and which do not require specialized personnel
to run, have been developed (immuno-enzymatic tests) for the detection of C. difficile toxins in the stool. These tests are
commercially available in the form of diagnostic kits. Although they are relatively less sensitive and demonstrate lower specificity
compared to the laboratory tests. They are used mainly in emergency situations and outbreaks when numerous patients must be
tested in a short time.
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Xpect™ test by a company called oxin uses a diluted faecal sample to detect both toxins (A and B) made by C. difficile.
The sample is mixed with conjugate and added to a test cassette. Results are clear within 20 minutes.
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