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Disease/health condition -
Chagas disease, Neglected tropical diseases
Trypanosoma cruzi IgG antibody
Assay format
Lateral flow RDT
Information History
First added in 2020
Purpose type
Screening, Aid to diagnosis, Surveillance
Purpose
For surveillance of Trypanosoma cruzi infection. To screen girls, women of childbearing age and pregnant women withotu previous treatment for Trypanosoma cruzi infection. To screen children and other at-risk populations. To aid in the diagnosis of chronic Trypanosoma cruzi infection (Chagas disease).* .
* RDT format recomended only in settings where laboratory-based methods are not available
Specimen types
Capillary whole blood
WHO prequalified or recommended products
N/A
GMDN
52480
Trypanosoma cruzi immunoglobulin G (IgG) antibody IVD, kit, rapid ICT, clinical
A collection of reagents and other associated materials intended to be used for the qualitative and/or quantitative detection of immunoglobulin G (IgG) antibodies to the parasitic protozoan Trypanosoma cruzi in a clinical specimen within a short period, relative to standard laboratory testing procedures, using an immunochromatographic test (ICT) method. This test is commonly used in the laboratory or in point-of-care analyses.
The medical device term(s), code(s) and definition(s) in this section were retrieved from databases external to WHO. As there might be more than one name, definition and “Nomenclature Code” related to the specific medical device, please consult https://gmdnagency.org GMDN ®. © GMDN Agency 2005-2024EMDN
W0105090499
PARASITES - RT & POC - OTHER
The code(s) and term(s) in this section were observed and retrieved from public databases and have not been validated by health regulatory authorities. Please consult your regulatory agency and EMDN site: https://webgate.ec.europa.eu/dyna2/emdnWHO supporting publications
Pan American Health Organization. Guidelines for the diagnosis and treatment of Chagas disease. Washington, D.C.: PAHO, 2019. https://iris.paho.org/bitstream/handle/10665.2/49653/9789275120439_eng.pdf ; Organización Panamericana de la Salud. Guía para el diagnóstico y el tratamiento de la enfermedad de Chagas. Washington, D.C.: OPS; 2018. https://iris.paho.org/bitstream/handle/10665.2/49653/9789275320433_spa.pdf
Technical specifications
N/A
SAGE IVD recommended including the Trypanosoma cruzi IgG antibody test category in EDL 3:
• as a disease-specific IVD for use in community settings and health facilities without laboratories, and as a disease-specific IVD for use in clinical laboratories (EDL 3, Sections I.b and II.b, Neglected tropical diseases);
• using an immunoassay format or an RDT (only in settings where laboratory-based methods are not available);
• for surveillance of Trypanosoma cruzi infection;
• to screen girls, women of childbearing age and pregnant women without previous treatment for Trypanosoma cruzi infection;
• to screen children and other at-risk populations; and
• to aid in the diagnosis (RDT) or to diagnose (immunoassay) chronic Trypanosoma cruzi infection (Chagas disease). The group noted that an immunoassay to screen for T. cruzi in blood donations is already listed in the EDL 2, as a disease-specific IVD for blood screening laboratories (Section II.c); but highlighted the potential value of this test category for screening organ donors too. It recommended reviewing Section II.c of the EDL to include donated organs as well as blood.
• as a disease-specific IVD for use in community settings and health facilities without laboratories, and as a disease-specific IVD for use in clinical laboratories (EDL 3, Sections I.b and II.b, Neglected tropical diseases);
• using an immunoassay format or an RDT (only in settings where laboratory-based methods are not available);
• for surveillance of Trypanosoma cruzi infection;
• to screen girls, women of childbearing age and pregnant women without previous treatment for Trypanosoma cruzi infection;
• to screen children and other at-risk populations; and
• to aid in the diagnosis (RDT) or to diagnose (immunoassay) chronic Trypanosoma cruzi infection (Chagas disease). The group noted that an immunoassay to screen for T. cruzi in blood donations is already listed in the EDL 2, as a disease-specific IVD for blood screening laboratories (Section II.c); but highlighted the potential value of this test category for screening organ donors too. It recommended reviewing Section II.c of the EDL to include donated organs as well as blood.
The Trypanosoma cruzi IgG test has the potential to significantly increase access to diagnosis and, consequently, treatment in endemic countries. Automated tests have improved performance compared with other formats, but their complexity and costs could limit their use in countries where Chagas disease is endemic. In these cases, RDTs can be used. SAGE IVD members highlighted the debate surrounding the need for one or two positive tests to diagnose Trypanosoma cruzi infection; the group also noted that while current WHO/PAHO guidelines do not recommend using RDTs as stand-alone tests, new evidence indicates their potential use as diagnostic tools in endemic countries. Further evidence is being generated to confirm this finding. SAGE IVD sought advice from WHO’s Neglected Tropical Diseases team on the potential use of the Trypanosoma cruzi test in primary care settings.
The submission did not include enough details about the different Trypanosoma cruzi IgG detection assays available. Many different immunoassay formats exist (e.g. ELISA, immunofluorescence assay, haemagglutination inhibition assay (IHA), chemioluminescent microparticle immunoanalysis (CMIA) and RDT) which are used for different purposes, mainly chronic Chagas disease diagnosis and Trypanosoma cruzi infection surveillance. The diagnostic algorithms and immunoassays used vary with the different purposes, populations targeted and regions.
Several recent systematic reviews have identified and pooled studies of the accuracy of immunologically based tests which show that they have high levels of performance, suitable for use across different settings. Estimates of sensitivity for ELISA, ICT/RDT and CMIA are 97% (CI: 96–98%), 94% (CI: 91–96%) and 99% (CI: 97–100%), respectively. Estimates of specificity for ELISA, ICT/RDT and CMIA are 98% (CI: 97–99%), 97% (CI: 96–98%) and 98% (CI: 91–99%), respectively.
PAHO guidelines have carefully considered the consequences of test errors in different circumstances and make clear recommendations as to which tests are preferable in different settings.
World Health Organization. (2021). The selection and use of essential in vitro diagnostics: report of the third meeting of the WHO Strategic Advisory Group of Experts on In Vitro Diagnostics, 2020 (including the third WHO model list of essential in vitro diagnostics). World Health Organization. https://iris.who.int/handle/10665/339064