Ova and Parasite Exam, Fecal (Immunocompromised or Travel History) should be used only in patients with appropriate risk factors (eg, immunocompromised, bloody diarrhea, persistent diarrhea [≥14 days], or chronic diarrhea [>30 days]). Even in the presence of these risk factors, specific pathogen testing is preferred, and recommended tests include Gastrointestinal Parasite and Microsporidia by PCR or Gastrointestinal Parasite Panel by PCR.
Shane AL, Mody RK, Crump JA, et al. 2017 Infectious Diseases Society of America Clinical Practice Guidelines for the Diagnosis and Management of Infectious Diarrhea. Clin Infect Dis. 2017; 65 (12): 1963-1973.