User:Gastro guy/diag work

=List of Gastroinestinal Infections=

Viral:

Bacterial:

Protist:

Multicellular:

=Patient Interview=

=Laboratory Tests=

Genetic Detection (PCR Testing)
Sensitivity of PCR Tests:


 * One report of a novel 2-step PCR test claimed to be able to detect as few as 1-2 Schistosoma mansoni organisms/gram of feces.

Serum antibody testing
=Causes Diagnostic Failure=

One study of persistent diarrhea in 604 US children found that while some cases were attributable to viral infections, no known infectious element could be identified in the majority (59%) of cases.

Failure to understand test results
A 1996 survey of 2839 in 5 states found that only 44% ordered a stool culture when last seeing a patient for acute diarrhea. 28% of the physicians did not know whether the stool culture would detect Entero-toxic E. Coli, and 40% did not know whether it would detect Yersina or Vibrio infection.

Variable quantity of infectious material in stool sample
Some tests rely on the ability to detect infectious material in a stool sample. However, the quantity of infectious material present in the stool of an infected person has been found to be highly variable.

A study of the ability to detect Cryptosporidium in formalin preserved stool samples followed by staining found that 10,000 cysts/gram were necessary for 100% detection in watery stools, and 50,000 cysts/gram were necessary for detection in formed stools. The study concluded that this, which is the most commonly used diagnostic procedure, may fail to detect infectio in patients.

In some cases, researchers have noted the quantity of an organism shed is insufficient even for PCR testing.

=References=