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Evaluación comparativa de antígeno liofilizado y antígeno líquido en la Prueba de Aglutinación Directa para el serodiagnóstico de la Leishmaniasis Visceral
Author(s) -
Jacquet Diane,
Boelaert Marleen,
Seaman Jill,
Rijal Suman,
Sundar Shyam,
Menten Joris,
Magnus Eddy
Publication year - 2006
Publication title -
tropical medicine and international health
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.056
H-Index - 114
eISSN - 1365-3156
pISSN - 1360-2276
DOI - 10.1111/j.1365-3156.2006.01743.x
Subject(s) - visceral leishmaniasis , direct agglutination test , leishmaniasis , protozoal disease , freeze drying , virology , medicine , serology , immunology , chemistry , malaria , chromatography , antibody
Summary Objective The direct agglutination test (DAT) for visceral leishmaniasis (VL) with liquid (LQ) antigen is known to be only moderately reproducible because of inter‐observer and batch‐to‐batch variability as well as its sensitivity to temperature and shaking during transport. We evaluated a DAT with freeze‐dried (FD) antigen and compared it with the LQ antigen version. Methods Blood samples of clinical VL suspects and healthy endemic controls were collected in Sudan, Nepal and India. Both test versions were performed in duplicate in the respective countries and in the reference laboratory. Interbatch variability and stability tests were conducted and agreement was examined within and between centres on a dichotomic scale by Cohen's kappa as well as on a continuous scale through Bland–Altman plots. Results The FD antigen remains fully active even after storage at 45 °C for 24 months. Using a cut‐off titre of 1 : 6400, the agreement between the FD and the LQ formats was excellent. Conclusion The major advantages of FD antigen are its better stability at higher temperatures and its longer shelf life, which make it much more suitable than the LQ version for use in the field.