Diagnosis Of Human Giardiasis

Although progress has been made in the non-morphological diagnosis of Giardiasis, examination (usually of feces) by microscopy remains the cornerstone in the diagnosis of intestinal parasitic infections. Routine examination of stool specimens is the best known and most frequently performed laboratory procedure worldwide in which almost all intestinal parasites can be detected at the same time. In Europe, standard methods in the laboratory diagnostics of enteric parasitoses, including Giardia, comprise the direct microscopic examination of the wet mount, and the examination of material from a stool concentrate. There is however an increasing trend towards routine use of fixatives, permanent staining, and multiple sampling techniques as these methods have been proven to enhance the diagnostic yield considerably.Advances in the biomedical sciences however have led to the non-morphological laboratory diagnosis of Giardiasis. Immunoassays to detect copro-antigens are gradually being introduced into routine diagnostics, particularly in larger laboratories processing large numbers of samples. PCR-based methods not only have exquisite sensitivity and specificity but also enables Giardia assemblage identification, but only few diagnostic laboratories are well placed to undertake these methods. These new parasite specific techniques may aid diagnosis and should be considered for adoption into the routine diagnostic algorithm. Once they have been evaluated fully and compared with accepted methods in individual laboratories or as interlaboratory quality assurance investigations they can be regarded as an adjunct to the conventional detection and identification techniques used for laboratory diagnosis.