Яйца и личинки гельминтов, простейшие и их цисты в кале методом обогащения (PARASEP)

Stool exam for helminth eggs and larvae, protozoa and their cysts (Parasep) is a concentration-based microscopic assay that identifies intestinal parasites in feces. It supports diagnosis of intestinal parasitic infections, including asymptomatic carriage, by concentrating ova, larvae, cysts, and oocysts prior to microscopy. The method is also used to document parasite clearance following antiparasitic therapy. The concentration step increases yield when parasite burden is low or organism shedding is intermittent.

Intestinal parasitic infections are widespread globally and contribute to gastrointestinal dysfunction, allergic phenomena, and systemic morbidity. Many species infect humans; common agents include Ascaris spp., hookworms, pinworms, Taenia spp., and Trichinella, as well as protozoa such as Giardia and intestinal amoebae. Transmission typically reflects breaks in sanitation, contaminated drinking water, unwashed produce, and inadequately cooked meat or fish. Clinical presentations range from asymptomatic carriage to severe diarrhea, cramping abdominal pain, malnutrition with malabsorption, and profound anemia. Light microscopic examination of stool remains the cornerstone of diagnosis. Direct smears have limited sensitivity because parasite concentrations may be low and shedding is intermittent. Concentration techniques improve detection and, compared with older open enrichment procedures, reduce hands-on complexity and exposure risk for laboratory personnel. Closed concentration systems such as Parasep provide a rapid and reliable approach to recover ova, larvae, cysts, and oocysts before microscopy. In the Parasep method, stool is mixed with reagents in a sealed tube and centrifuged. Differences in specific gravity separate debris while parasitic elements concentrate into a single layer for subsequent microscopic review. Because excretion of eggs and cysts is not continuous, a negative result does not exclude infection; repeat examinations at intervals of several days are appropriate when symptoms persist.