Comparison of Laboratory Techniques For the Diagnosis of Giardia Intestinalis

Objective: To evaluate the sensitivity and specificity of three laboratory techniques for the diagnosis of Giardia intestinalis. Materials and Methods: 31 fecal samples from pre schoolers were submitted to microscopic examination with SSF-Lugol, the Ritchie concentration method and the “Giardia-Stri...

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Bibliographic Details
Main Authors: Marinella Calchi, E. Acurero, R. Villalobos, M Colina, L. Di Toro, C. Villalobos
Format: Article in Journal/Newspaper
Language:English
Spanish
Published: Universidad del Zulia,Facultad de Medicina,Departamento de Enfermedades Infecciosas y Tropicales 2014
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Online Access:https://doaj.org/article/421acb53a57041cb9e366f0665195f98
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Summary:Objective: To evaluate the sensitivity and specificity of three laboratory techniques for the diagnosis of Giardia intestinalis. Materials and Methods: 31 fecal samples from pre schoolers were submitted to microscopic examination with SSF-Lugol, the Ritchie concentration method and the “Giardia-Strip” immunological method. The Ritchie technique was considered the “gold standard.“ Results: G. intestinalis cysts were identified in 6 samples (19.35%) using the Ritchie technique. The fresh test identified 5 cases of protozoan cysts (16.1%), showing a sensitivity of 83 % and specificity of 100 %. The Giardia-Strip identified cysts in 4 samples (12.9%) with 66.66 % sensitivity and 100% specificity. The positive predictive value for the “Giardia Strip” method was 14% and the negative predictive value was 93%. The fresh test showed a positive predic tive value of 100% and a negative predictive value of 96 %. Conclusions: Ritchie concentrate and the fresh test showed higher sensitivity and specificity in the diagnosis of Giardia intestinalis, when samples contain only cysts. However, the Giardia-Strip method proved faster in obtaining results.