from David J. Bartley and Hany M. Elsheikha writing in Essentials of Veterinary Parasitology:
Accurate diagnosis of parasitic infections is a prerequisite for successful treatment and control of these pathogens. Errors in the diagnosis can lead to the initiation of unnecessary therapies, or delays in initiating the correct therapy. Thus, the clinicians must maintain a sharp index of suspicion and must rely on detailed history and clinical manifestations, to raise the possibility of a parasitic disease. Even though the diagnosis can be difficult, and definitive identification of the parasites can be challenging particularly in the non-endemic settings. Therefore, laboratory testing for detection and identification of the parasitic agents is required to complement clinical judgement, enhance the clinician's ability to select specific anti-parasitic drugs, and ultimately improve patient care. A wide range of laboratory procedures are available for the diagnosis of parasitic infections. These procedures vary in methodology, expense, availability, sensitivity, and specificity. In this chapter, the standard techniques used in the laboratory diagnosis of parasitic infections are discussed.
Further reading: Essentials of Veterinary Parasitology