Wallach's Interpretation of Diagnostic Tests: Pathways to Arriving at a Clinical Diagnosis (1421 page)

   Considerations

   Specimens should be kept between 2°C and 25°C during transport and protected against freezing or exposure to excessive heat.

   Specimens can be stored up to 48 hours at 15–25°C or 5 days at 2–8°C before testing.

   PCR test can be affected by genetic rearrangements or the presence of rare bacterial DNA variants.

   Mutations or polymorphisms in primer- or probe-binding regions may affect detection of new or unknown MRSA/SA variants resulting in a false-negative result with the PCR assay.

STOOL CULTURE (ROUTINE)

   Definition

Routine stool culture should be considered for patients with acute diarrheal illness who are producing frequent, loose stools. Nausea, abdominal pain, and vomiting may be present. Fever may be present, but is not a prominent feature in uncomplicated enteric infection. Fluid loss, especially in infants and small children, may be severe and associated with complications including electrolyte imbalance and cardiovascular instability.

   Special Collection and Transport Instructions

   Acceptable specimens: liquid stool (feces), rectal swab.

   Sterile collection containers are not required. Specimens may be collected in clean containers. The container should be free of detergent or preservative.

   Specimens should be transported promptly to the laboratory. If transport will be delayed >2 hours, use of a transport medium, like Cary-Blair, is recommended.

   Three specimens, collected on consecutive days, are recommended for sensitive detection of enteric pathogens, especially for patients at risk for complication or at increased risk for transmission of enteric pathogens, like food handlers.

   Specimens collected on toilet paper or diapers are not acceptable. Specimens contaminated by urine are not acceptable.

   Use