Comparison between spontaneous sedimentation method and Paratest® for the diagnosis of intestinal parasitic infections

Abstract

Correct diagnosis of parasitic infections is essential for the treatment of individuals avoiding indiscriminate use of anthelmintics which increases drug resistance. In a comparative study between the spontaneous sedimentation technique and Paratest(®), 140 stool samples were analyzed for the detection of parasites. The prevalence was 12.7% obtained by the spontaneous sedimentation method but only 5.7% using Paratest(®). Paratest(®) has shown a high proportion of false-negative results, lower sensitivity and negative predictive values compared with the spontaneous sedimentation method. Further optimization and studies of the Paratest(®) method are necessary for wider use in clinical diagnosis.

Infección por Strongyloides stercoralis: metanálisis sobre evaluación de métodos diagnósticos convencionales (1980-2013)

“…La detección microscópica de las larvas de S. stercoralis en las heces puede realizarse por varios métodos 5 , siendo el examen directo en heces el que se utiliza de manera rutinaria en los laboratorios clíni-cos, aunque debido a su baja sensibilidad en la detección de este nemátodo, en algunas ocasiones se requieren procedimientos que aumenten la sensibilidad de la prueba, como son el análisis de varias muestras, para aumentar la probabilidad de detección de las larvas 16,17 o las técni-cas de concentración, entre las que se encuentra la técnica de formol-éter, formalina etil acetato y sedimentación espontánea o Hoffman [18][19][20] . Otras técnicas utilizadas para el diagnóstico de S. stercoralis son la técnica de Bearman y el en placa de ágar 21 .…”

Comparison of the performance of two spontaneous sedimentation techniques for the diagnosis of human intestinal parasites in the absence of a gold standard

“…a diagnostic test with 100% accuracy against which the sensitivity and specificity of other tests are estimated) are available in parasitology and, in particular, do not exist for the detection of intestinal parasite infection (Basso et al, 2013;Tarafder et al, 2010). Nevertheless, most studies estimating the sensitivity and specificity of tests for the diagnosis of intestinal parasites consider the results of one of two tests compared (usually the traditional test) or the combination of the results of several diagnostic tests as the gold standard (Brandelli et al, 2011;Carvalho et al, 2012;Devera et al, 2008a;Dogruman-Al et al, 2010;Glinz et al, 2010;Inês et al, 2011;Knopp et al, 2011;Levecke et al, 2011;Steinmann et al, 2012). These practices have led to biased estimations of accuracy.…”

“…Among the diagnostic tests based on optical microscopy those based on spontaneous sedimentation are among the least expensive and easiest to perform and enable the simultaneous detection of helminth and protozoan intestinal infections (Brandelli et al, 2011;Camacho et al, 2013;Carvalho et al, 2012;Ribeiro and Furst, 2012;Tello et al, 2012). For these reasons, in some economically underdeveloped settings their use is preferred over the tests based on centrifuge-sedimentation or centrifuge-flotation.…”

“…The spontaneous sedimentation technique (SST) (also known as the Lutz technique or the Hoffman, Pons and Janer technique) is a traditional test widely used for clinical diagnosis and epidemiological surveys in Brazil and, also, Venezuela (Brandelli et al, 2011;Carvalho et al, 2012;de Souza et al, 2007;Devera et al, 2008a,b;Pinheiro et al, 2011;Santos et al, 2013;Velásquez et al, 2005). In this test, stool samples (previously preserved or diluted in water) are filtered through a gauze strip into a conical cup and subsequently submitted to sedimentation in tap water for 1 or 2 h (De Carli, 2007a).…”

Diagnosis of Intestinal Parasitoses: Comparison of Two Commercial Methods for Faecal Concentration Using a Polyparasitized Artificial Liquid Stool

“…We chose this kit for its operator safety, it does not use formalin, and ethyl acetate replaces ether in the detergent solution. Briefly, parasite concentration is achieved by preparing two non-miscible phases, the first aqueous (aceto-acetic buffer pH 5) and the second organic (ethyl acetate) [1]. A new sedimentation kit for parasite concentration in faeces was recently marketed (EasyPara®, Servibio, Meudon, France).…”