eDocTalk article

Legacy Lab now rejecting repeat <br>Clostridium difficile specimens

January 2013

Legacy Laboratory Services is rejecting specimens sent on formed stools or repeat testing within five days of the original test. 

According to the IDSA/SHEA guidelines, testing for C. difficile or its toxins should only be performed on diarrheal (unformed) stools, unless ileus is suspected. A single specimen at the onset of a symptomatic episode is usually sufficient and routine testing of multiple specimens is NOT supported due to the sensitivity of the testing method. 

Testing on asymptomatic patients is not clinically useful, including use as a test of cure. Specimens that are formed or hard will be rejected (unless ileus is suspected), and rectal swabs and fluid obtained at colonoscopy are not acceptable and will be rejected.

C. difficile continues to challenge clinicians, epidemiologists, and microbiologists and clostridium difficile infection has increased substantially in the last decade. For the detection of toxin, Legacy utilizes a two-step algorithm (ordered as C Diff Toxin). Our algorithm begins with detecting the presence/absence of regardless of its toxigenic capability. If glutamate dehydrogenase (GDH) is positive by EIA assay, the specimen proceeds to the Xpert PCR assay for a confirmatory toxin test. Turnaround time is 24 hours.  

For more information, contact Claudia Atherton, system manager for Microbiology, at 503-413-2828 or Mitchell Ryan, M.D., medical director for Microbiology, at 503-413-7636.

An important reminder

Order Enteric Contact Precautions for suspect or known C. difficile or Norovirus. These patients should remain in precautions until 24 hours after the last diarrhea stool. Wear a gown and gloves at all times in the patient’s room and wash hands with soap and water only immediately following gown and glove removal. Daily disinfect frequently touched surfaces with bleach wipes only.