Application of WHO International Biological Reference Standards to evaluate commercial serological tests for chronic Chagas disease.

BACKGROUND Chagas disease, resulting from Trypanosoma cruzi infections, continues to be a health concern mainly in Latin American countries where the parasite is endemic. The laboratory diagnosis of a chronic infection is determined through serological assays for antibodies against T. cruzi and several tests are available that differ in key components, formats and methodologies.

Quality Control in Screening for Infectious Diseases at Blood Banks. Rationale and Methodology.

Quality control procedures are indispensable to ensure the reliability of the results provided by laboratories responsible for serological screening in blood banks. International recommendations on systems of quality management classify as a top component the inclusion of two types of control: (a) internal quality control (IQC) and (b) external quality control (EQC). In EQC it is essential to have, at least, a monthly frequency of laboratory assessment.

Comparative evaluation of 11 commercialized rapid diagnostic tests for detecting Trypanosoma cruzi antibodies in serum banks in areas of endemicity and nonendemicity.

Chagas disease is one of the main public health issues in Latin America. Increasingly during the past few decades, Trypanosoma cruzi infection has been detected in North America, Europe, and the Western Pacific, mainly as a result of population movement. The limited availability of rapid serological diagnostic tests hinders rapid diagnosis and early treatment in areas of endemicity and nonendemicity.

Evaluation of serological tests to identify Trypanosoma cruzi infection in humans and determine cross-reactivity with Trypanosoma rangeli and Leishmania spp.

Five commercially available enzyme-linked immunosorbent assays (ELISAs), one in-house ELISA, and two hemagglutination assays were evaluated to determine their diagnostic accuracy for Chagas' disease in two studies. In study 1, ELISA kits showed 100% sensitivity, but specificities ranged from 82.84% to 100% when leishmaniasis cases were included and from 95.

[External serology quality control programs developed in Latin America with the support of PAHO from 1997 through 2000].

Objective: To evaluate the quality of serological screening of blood donors in five groups of blood banks in Latin America that participated over the 1997-2000 period in an external serology control project developed with support from the Pan American Health Organization (PAHO).

Methods: With assistance from PAHO, the Serology Authority of the Pro-Blood Foundation/Blood Center of São Paulo (Fundação Pró-Sangue/Hemocentro de São Paulo), of São Paulo, Brazil, carried out the external quality control project and served as its "organizing center" (OC). The OC developed five external serology quality control "programs" (ESQCPs), or external evaluation activities, for the respective groups of participating blood banks.