Authors:

Abstract

Objectives
The current study was undertaken to compare the sensitivity, specificity, positive predictive value and negative predictive values of a dengue IgM rapid immunochromatography (ICT) assay with a dengue IgM capture ELISA for the detection of anti-dengue virus IgM in patients clinically suspected of having dengue fever (DF).

Methods
Blood samples (n=119) were collected from paediatric and adult patients suspected of having DF at Teaching Hospital, Peradeniya (THP) after 5 days of fever. The samples were analyzed for the presence of anti-dengue virus IgM using a commercial rapid dengue IgM ICT assay (Hexagon dengue, Human, Germany) and a commercial IgM capture ELISA (Panbio Diagnostics Inc, Australia) provided to THP by the Ministry of Health for the diagnosis of dengue fever.

Results
When tested using the rapid dengue IgM ICT assay, 80 blood samples were positive and 39 were negative for anti-dengue virus IgM. When tested using the dengue IgM ELISA, 100 sera were positive and 19 were negative for dengue IgM. Using the IgM capture ELISA as the comparator,  the sensitivity and the specificity of the rapid assay were 79% and 94.7% respectively with  a positive (PPV) and negative (NPV) predictive value  of 98.8% and 46.2%.

Conclusion
In comparison with the results of the IgM capture ELISA, the low sensitivity and NPV for anti-dengue virus IgM detection by the rapid dengue IgM ICT assay was noted. The low sensitivity and NPV means that patients with DF will be missed when using this test. In contrast, the high specificity and PPV indicate that this rapid assay is able to detect true positives. Since preliminary screening of DF is carried out widely using these rapid tests, the strengths and limitations of this and other similar tests require validation before use in diagnostic laboratories

DOI: http://dx.doi.org/10.4038/sljid.v4i2.5925

Sri Lankan Journal of Infectious Diseases 2014; Vol.4(2):77-82

Keywords: Dengue fever, rapid tests, IgM ELISA, Sri Lanka