Giardia lamblia, Direct Detection EIA and Cryptosporidium, Direct Detection EIA

Fecal specimens for parasitic examination should be collected before initiation of antidiarrheal therapy or antiparasitic therapy. The highest yield on hospitalized patients occurs when diarrhea is present on admission or within 72 hours of admission. The onset of diarrhea more than 72 hours after admission is usually caused by Clostridium difficile toxin rather than parasites or the usual stool pathogens. The following recommendations are made for efficient and cost-effective diagnosis of diarrheal disease in patients admitted with gastroenteritis.

• Submit one or two specimens per diarrheal illness immediately. Consider first requesting EIAs for Giardia and Cryptosporidium (See test Giardia lamblia, Direct Detection EIA [182204] or Giardia lamblia, Direct Detection EIA and Cryptosporidium, Direct Detection EIA [183558]). Giardia and Cryptosporidium are the most common causes of parasitic gastroenteritis in the United States.

• If EIAs are negative, request add-on testing for Ova and Parasites Examination [008623], and submit an additional specimen after five days for O&P examination.

• Also consider testing for unusual stool pathogens (Cyclospora Smear, Stool [183145]), especially in the immunocompromised patient.

Maintain stool specimens in O&P transport with formalin at room temperature or refrigerate and test within 18 months of collection. Stool in sterile container should be frozen or can be kept refrigerated if tested within 24 hours.

Inappropriate specimen transport device; specimens in PVA; specimens other than stool; specimens received other than described; inadequate labeling; specimen in Cary Blair medium