Sensitivity and specificity of three ELISA-based assays for discriminating primary from secondary acute dengue virus infection.
BACKGROUND
Discrimination between primary and secondary dengue virus infection traditionally has been performed using the hemagglutination inhibition (HI) test. However, this test has practical limitations and disadvantages.


OBJECTIVE
To evaluate the ability of three ELISA-based methods (IgG avidity test, IgM/IgG ratio and IgG titer) to discriminate primary from secondary dengue infection.


METHODS
Serum samples from convalescent-phase patients with confirmed acute, primary (n=46) or secondary (n=33) dengue virus infection were tested using three ELISA-based methods. A ROC curve was employed to establish the cut-off points and to evaluate the ability of the three methods to distinguish between acute, primary and secondary dengue virus infection.


RESULTS
All three assays exhibited sensitivity and negative predictive values of 100% for defining secondary infection. The specificity and positive predictive values were respectively 97.8% and 93.7% for the IgG avidity test, 95.7% and 88.2% for the IgM/IgG ratio assays, and 97.8% and 93.7% for the IgG titer assay.


CONCLUSIONS
All three ELISA-based assays proved reliable tools for discriminating between acute, primary and secondary dengue virus infection when using serum samples from convalescent-phase patients.
de Souza
Vanda Akico Ueda Fick
VA
Laboratório de Virologia (LIM-HC)--Instituto de Medicina Tropical de São Paulo e Departamento de Moléstias Infecciosas e Parasitárias da Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP, Brazil.
Tateno
Adriana Fumie
AF
Oliveira
Renato Reis
RR
Domingues
Renan B
RB
Araújo
Evaldo Stanislau
ES
Kuster
Gustavo W
GW
Pannuti
Cláudio Sérgio
CS
D000208:Acute Disease; D000914:Antibodies, Viral / Q000097:blood*; D000915:Antibody Affinity; D003289:Convalescence; D003715:Dengue / Q000175:diagnosis* / Q000276:immunology / Q000503:physiopathology / Q000821:virology; D003716:Dengue Virus / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D007075:Immunoglobulin M / Q000097:blood; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity
D000914:Antibodies, Viral; D007074:Immunoglobulin G; D007075:Immunoglobulin M