Iatreia (May 2010)
Now ICT malaria Pf/Pv® versus microscopy (thick-smear, thin smear) for diagnosis of malaria in Urabá (Colombia) Now ICT malaria Pf/Pv® frente a microscopía (gota gruesa-extendido) para diagnóstico de malaria en Urabá (Colombia)
Abstract
<p class="MsoNormal" style="text-align: justify; line-height: normal; margin: 0cm 0cm 0pt; mso-layout-grid-align: none;"><strong><span style="font-family: ";Times New Roman";,";serif";; font-size: 12pt; mso-ansi-language: EN-US;" lang="EN-US">Problem: </span></strong><span style="font-family: ";Times New Roman";,";serif";; font-size: 12pt; mso-ansi-language: EN-US;" lang="EN-US">To date, there are only three reports from Colombia about the malaria diagnostic test Now ICT Malaria Pf / Pv ® (NowICT). The results from these studies showed major differences in sensitivity and specificity.</span></p><p class="MsoNormal" style="text-align: justify; margin: 0cm 0cm 10pt;"><span style="line-height: 115%; font-family: ";Times New Roman";,";serif";; font-size: 12pt; mso-ansi-language: EN-US;" lang="EN-US"> </span></p><p class="MsoNormal" style="text-align: justify; line-height: normal; margin: 0cm 0cm 0pt; mso-layout-grid-align: none;"><strong><span style="font-family: ";Times New Roman";,";serif";; font-size: 12pt; mso-ansi-language: EN-US;" lang="EN-US">Objective: </span></strong><span style="font-family: ";Times New Roman";,";serif";; font-size: 12pt; mso-ansi-language: EN-US;" lang="EN-US">To evaluate the diagnostic performance of NowICT compared to thick smear for the diagnosis of Plasmodium infection in matched blood samples from mothers (maternal peripheral blood), umbilical cord and placenta.</span></p><p class="MsoNormal" style="text-align: justify; line-height: normal; margin: 0cm 0cm 0pt; mso-layout-grid-align: none;"><strong><span style="font-family: ";Times New Roman";,";serif";; font-size: 12pt; mso-ansi-language: EN-US;" lang="EN-US"> </span></strong></p><p class="MsoNormal" style="text-align: justify; line-height: normal; margin: 0cm 0cm 0pt; mso-layout-grid-align: none;"><strong><span style="font-family: ";Times New Roman";,";serif";; font-size: 12pt; mso-ansi-language: EN-US;" lang="EN-US">Methods: </span></strong><span style="font-family: ";Times New Roman";,";serif";; font-size: 12pt; mso-ansi-language: EN-US;" lang="EN-US">We used a closed (blinded/masked) and parallel design for the evaluation of a diagnostic test. The sample size was calculated with statistical and epidemiological parameters; this consisted of 131 thick smears from maternal peripheral blood. Blood samples from placenta and umbilical cord were also studied (386 samples tested in total).</span></p><p class="MsoNormal" style="text-align: justify; line-height: normal; margin: 0cm 0cm 0pt; mso-layout-grid-align: none;"><strong><span style="font-family: ";Times New Roman";,";serif";; font-size: 12pt; mso-ansi-language: EN-US;" lang="EN-US"> </span></strong></p><p class="MsoNormal" style="text-align: justify; line-height: normal; margin: 0cm 0cm 0pt; mso-layout-grid-align: none;"><strong><span style="font-family: ";Times New Roman";,";serif";; font-size: 12pt; mso-ansi-language: EN-US;" lang="EN-US">Results: </span></strong><span style="font-family: ";Times New Roman";,";serif";; font-size: 12pt; mso-ansi-language: EN-US;" lang="EN-US">The sensitivity of Now ICT for detection of P. vivax was below 70% in any of the samples (maternal blood, placental blood or cord blood). The specificity was greater than 99%. Values for P. falciparum infection were not calculated since too few cases were detected.</span></p><p class="MsoNormal" style="text-align: justify; line-height: normal; margin: 0cm 0cm 0pt; mso-layout-grid-align: none;"><span style="font-family: ";Times New Roman";,";serif";; font-size: 12pt; mso-ansi-language: EN-US;" lang="EN-US"> </span></p><p class="MsoNormal" style="text-align: justify; line-height: normal; margin: 0cm 0cm 0pt; mso-layout-grid-align: none;"><strong style="mso-bidi-font-weight: normal;"><span style="font-family: ";Times New Roman";,";serif";; font-size: 12pt; mso-ansi-language: EN-US;" lang="EN-US">Conclusions:</span></strong><span style="font-family: ";Times New Roman";,";serif";; font-size: 12pt; mso-ansi-language: EN-US;" lang="EN-US"> Now ICT Malaria Pf / Pv® is not a useful diagnostic tool in Colombia since the sensitivity for the most frequent species in the country, P. vivax, is poor. This interpretation is consistent with the WHO’s general conclusions about the state of development of rapid diagnostic tests for malaria.</span></p> <p class="MsoNormal" style="text-align: justify; line-height: normal; margin: 0cm 0cm 0pt; mso-layout-grid-align: none;"><strong><span style="font-family: ">Problema: </span></strong><span style="font-family: ">solo conocemos tres informes para Colombia de la prueba diagnóstica de malaria Now ICT Malaria Pf/Pv ® (NowICT); esos estudios tuvieron resultados de sensibilidad y especificidad muy diferentes.</span></p><p class="MsoNormal" style="text-align: justify; line-height: normal; margin: 0cm 0cm 0pt; mso-layout-grid-align: none;"><strong><span style="font-family: "> </span></strong></p><p class="MsoNormal" style="text-align: justify; line-height: normal; margin: 0cm 0cm 0pt; mso-layout-grid-align: none;"><strong><span style="font-family: ">Objetivo: </span></strong><span style="font-family: ">evaluar la capacidad diagnóstica de NowICT frente a la gota gruesa para el diagnóstico de infección plasmodial en sangres periférica materna, del cordón umbilical y placentaria.</span></p><p class="MsoNormal" style="text-align: justify; line-height: normal; margin: 0cm 0cm 0pt; mso-layout-grid-align: none;"><strong><span style="font-family: "> </span></strong></p><p class="MsoNormal" style="text-align: justify; line-height: normal; margin: 0cm 0cm 0pt; mso-layout-grid-align: none;"><strong><span style="font-family: ">Metodología: </span></strong><span style="font-family: ">diseño paralelo y enmascarado para evaluación de una prueba diagnóstica. El tamaño de la muestra se calculó con parámetros epidemiológicos y estadísticos y fue de 131 muestras de sangre periférica materna; también se examinaron sendas muestras de sangre placentaria y de cordón umbilical.</span></p><p class="MsoNormal" style="text-align: justify; line-height: normal; margin: 0cm 0cm 0pt; mso-layout-grid-align: none;"><strong><span style="font-family: "> </span></strong></p><p class="MsoNormal" style="text-align: justify; line-height: normal; margin: 0cm 0cm 0pt; mso-layout-grid-align: none;"><strong><span style="font-family: ">Resultados: </span></strong><span style="font-family: ">se evaluaron en total 386 muestras. La sensibilidad de NowICT para P. vivax no alcanzó</span></p><p class="MsoNormal" style="text-align: justify; line-height: normal; margin: 0cm 0cm 0pt; mso-layout-grid-align: none;"><span style="font-family: ">70% en ninguna de las fuentes (madre, placenta, cordón). La especificidad mínima fue de 99%. Los valores para P. falciparum no se calcularon porque los casos fueron pocos.</span></p><p class="MsoNormal" style="text-align: justify; line-height: normal; margin: 0cm 0cm 0pt; mso-layout-grid-align: none;"><strong><span style="font-family: "> </span></strong></p><p class="MsoNormal" style="text-align: justify; line-height: normal; margin: 0cm 0cm 0pt; mso-layout-grid-align: none;"><strong><span style="font-family: ">Conclusión: </span></strong><span style="font-family: ">Now ICT malaria Pf/Pv® no es una herramienta diagnóstica útil en Colombia porque su sensibilidad para P. vivax es muy deficiente y en el país esta especie es la que predomina en la generación de malaria en humanos. Esta interpretación concuerda con las conclusiones generales de la OMS sobre el estado de desarrollo de las pruebas diagnósticas rápidas para malaria.</span></p><p> </p>
