C. diff Lab Tests, Study Shows Not All Are Equally Accurate

July 5, 2011

"Kimberle Chapin, M.D."

Kimberle Chapin, M.D.

A recent study published in the July issue of the Journal of Molecular Diagnostics has revealed that some laboratory tests are more accurate at detecting the Clostridium difficile toxin (C. diff) than others. The findings of a study conducted at the microbiology lab at Lifespan hospitals “indicate that a molecular method detects up to 50 percent more cases of C. diff than other methods.”

While molecular technology is more expensive, it allows for more cases to be identified and assists in patient safety efforts within the hospital in terms of preventing hospital-acquired C. diff infections.

The study’s lead author is Kimberle Chapin, M.D., director of the microbiology lab at Lifespan.

In Chapin’s study, she compared five different assays used in the laboratory for identifying C. diff. Her labs at Rhode Island Hospital/Hasbro Children’s Hospital, The Miriam Hospital and Newport Hospital perform 15,000 C. diff assays each year. The study evaluated the results of molecular versus non-molecular tests. Chapin says, “The molecular methods we tested detected between 35 and 54 percent more patients who were positive for C. diff than the non-molecular methods.”

Chapin says these findings bring up concerns in the number of unconfirmed cases of C. diff in hospitals that are not using molecular methods. “Through the use of molecular testing in our lab, combined with astute physicians and nurses requesting the tests, we were able to detect 50 percent more patients than we did prior to using molecular methods. Knowing the non-molecular tests did not find as many cases lead to patient safety concerns and the drive to implement the new method,” she says.


Press Release, Not all tests are created equal: Identifying C. diff in hospital labs.  EurekAlert!, July 5, 2011.

Chapin, KC, Dickenson, RA, Wu, F, and SB Andrea.  Comparison of Five Assays for Detection of Clostridium difficile ToxinThe Journal of Molecular Diagnostics, 13(4):395-400 (July 2011).

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