Evaluation of Commercially Available Assays for Diagnosis of Acute Dengue in Schoolchildren During an Epidemic Period in Medellin, Colombia

Abstract

During an active surveillance study in school children in Medellin, we assessed the performance of two diagnostic strategies for dengue virus. A total of 41 patients with suspected dengue acute infection were evaluated. Diagnostic strategies consisted of one combining Panbio(®) Dengue virus IgM and IgG Capture ELISAs (enzyme-linked immunosorbent assays) with reverse transcriptase polymerase chain reaction (RT-PCR) and another using a commercial rapid SD Bioline Dengue Duo (IgG/IgM + NS1 Ag) test. These two strategies were compared with the enzyme-linked immunospot microneutralization test (ELISPOT-MNT). The sensitivity and specificity were 53.9% and 80.0% for the combination of Panbio(®) ELISAs and RT-PCR tests, and 30.8% and 73.3% for the SD Bioline Duo test, respectively. ELISPOT-MNT detected 16.4% additional cases and revealed the presence of neutralizing antibodies in all the acute samples, evidencing that they were all secondary infections. In contrast, Panbio(®) and SD Dengue Duo rapid tests only classified 23.0% and 26.9% of the cases as secondary dengue infections, respectively. Cohen's kappa coefficient and McNemar's association tests demonstrated a significant disagreement between the two diagnostic strategies and ELISPOT-MNT. Overall, these results evidence the relatively poor performances of commercial assays for the diagnosis of acute and secondary dengue infections, compared with ELISPOT-MNT, and raise concern about the accuracy of these assays for the diagnostic of dengue in endemic areas.

Figure 1.

The enzyme-linked immunospot microneutralization test (ELISPOT-MNT₅₀) titers to each dengue virus serotype (DENV 1–4) in acute and convalescents samples from 26 cases of dengue infection. Box and whisker plot represent the range, median; and 25.0–75.0% interquartile ranges are shown for acute (A) and convalescent (C) samples for each dengue serotype. Antibodies titers are represented as an integer value along the y axis. 0 = lower than 1:20; 1 = 1:21–1:40; 2 = 1:41–1:80; 3 = 1:81–1:160; 4 = 1:161–1:320; 5 = 1:321–1:640; 6 = 1:641–1:1,280; 7 = 1:1,281–1:2,560; 8 = 1:2,561–1:6,400; 9 = 1:6,401–1:10,240; 10 = 1:10,241–1:40,960; 11 = 1:40,961–1:163,840 and 12 = higher than1:163,841.