What type of test can be performed on a stool specimen?

The selection of tests that can be performed on a stool specimen is primarily focused on gastrointestinal health and disease diagnosis. Stool specimens are particularly valuable for detecting occult blood, which can indicate gastrointestinal bleeding often associated with conditions such as polyps or colorectal cancer. They are also used to test for parasitic infections, which is vital for diagnosing gastrointestinal diseases caused by parasites like Giardia or Entamoeba histolytica. Additionally, microbiological studies can be performed to identify various pathogens, such as bacteria or viruses, contributing to gastrointestinal infections.

Other options do not pertain to stool specimens. Blood glucose testing is usually performed on blood samples to monitor diabetes or blood sugar levels, routine cytology is associated with the examination of cells for cancer or other diseases typically from tissues (such as Pap smears), and urinary pH testing is conducted on urine samples to assess kidney function or metabolic disorders. Thus, the correct answer aligns with the specific types of analyses that stool specimens can yield in a clinical setting.