Diagnostic testing for dengue improved; low-cost options sought

Clinical diagnosis for dengue has improved since 2007 due to the increasing accuracy of diagnostic testing, according to data presented at the 2014 European Congress of Clinical Microbiology and Infectious Diseases.

Champica Kasmari Bodinayake, MD, of the University of Ruhuna in Sri Lanka, and colleagues analyzed clinical and epidemiological data for adults and children, aged 2.8 to 85.6 years, with acute onset of fever. Blood specimens were obtained at enrollment and again 2 to 4 weeks later. Researchers conducted immunoglobulin G and IgM capture enzyme-linked immunosorbent assays on patients’ acute and convalescent samples; and virus isolation on acute samples of patients diagnosed with dengue by time of discharge.

Of the 409 patients diagnosed with acute undifferentiated febrile illness, 188 were diagnosed with acute dengue by laboratory criteria; 29 were diagnosed by virus isolation; 96 were diagnosed by serology; and 63 were diagnosed by isolation and serology. Patients diagnosed with dengue serologically or through a culture were younger, with a mean age of 30.8 years, and presented earlier.

Patients with dengue were more likely to have leukopenia at admission and develop thrombocytopenia during hospitalization. Seven patients met WHO criteria for dengue hemorrhagic fever.

Of the 39 patients who received dengue IgM testing, 31 tested positive. Clinical diagnosis of dengue at admission had a sensitivity of 53.7% (95% CI, 46.3-61), a specificity of 67% (95% CI, 60.3-73.1), and improved to 64.4% (95% CI, 57.1-71.2) and 71.5% (95% CI, 65.1-77.4), respectively, by time of discharge. Positive predictive value of clinical diagnosis of dengue at discharge was 65.8% (95% CI, 58.4-72.6).

“Clinical diagnosis of dengue fever improved from 2007 to 2012-2013, in the presence of an outbreak in southern Sri Lanka. Clinical diagnosis was supported by basic laboratory measures, including leukopenia and thrombocytopenia. The use of routine diagnostic testing for dengue was low. These findings highlight the need for greater access to low-cost, accurate diagnostic tests for dengue during both epidemic and non-epidemic periods,” the researchers concluded.

For more information:

Bodinayake CK. Abstract O230. Presented at: European Congress of Clinical Microbiology and Infectious Diseases; May 10-13, 2014; Barcelona, Spain.