New PCR-based GI panel for stool diagnostics and C. difficile testing update

The GLA microbiology lab is now performing a new PCR-based method for testing for gastrointestinal pathogenic microorganisms. This replaces routine stool bacterial cultures and also detects C. difficile, norovirus, and common parasites, including Entamoeba histolytica, Giardia lamblia, and Cryptosporidium.

A full list of the pathogens targeted with this test is available at:

This test is orderable as “GI Panel” in CPRS and is available from the Microbiology Test Order Screen that can be reached from many inpatient and outpatient order sets. Stool O&Ps and specific testing for Microsporidia now require ID approval.

Please note that for patients with new-onset diarrhea who are on or have recently received antibiotics, C. difficile PCR testing should be ordered, not the full GI Panel. C. difficile testing has also recently been updated, as all positive PCR tests (either from the GI Panel or the specific C. difficile PCR) will be reflexed for toxin immunoassay testing. Samples that are PCR positive and toxin negative are likely to represent colonization with C. difficile and not active infection.

Also remember that stool microbiology testing should be done on frankly liquid bowel movements (Bristol stool chart 7). Also do not test in the setting of recent laxatives, stool softener, or tube feed initiation.

Please contact the Infectious Diseases service (fellow pager UCLA 89321; antibiotic approval pager VA 73022) with any questions.