Clinical evaluation of dengue RNA, NS1, and IgM for diagnosis of dengue in Southern China

Abstract

In 2014, a large outbreak of dengue occurred in Guangzhou, China. This outbreak prompted us to evaluate NS1 and RNA for the early diagnosis of acute dengue infection, in addition to the combination with IgM antibody. We aimed to find the differences of three assays about dengue diagnosis. This study was an evaluation of diagnosis test. Based on WHO criteria 2009, dengue RNA, NS1, and IgM/IgG were detected from 294 patients (180 dengue patients, 114 non-dengue patients) by three diagnostic kits made in China. The χ(2) test, sensitivity, and specificity were used in statistical analysis. The ratios of dengue patients with low platelet counts (<100 × 10(9) /L 32.2%) or white blood cell counts (<4.0 × 10(9) /L 58.9%) were significantly higher compared to non-dengue patients (P < 0.05). Dengue NS1 was shown sensitive (93.9%) for diagnostic use. RNA had a better performance with 98.1% of sensitivity from day 1 to day 4 after illness onset. IgM performed better at day 5 or more with 74.0% of sensitivity. The diagnostic rate using a combination of RNA and IgM was 97.8% and 96.7% using NS1 and IgM. A patient with low platelet and white blood cell counts needs additional tests for dengue during an epidemic. RNA and NS1 were most valuable for early diagnosis of dengue, whereas IgM was best suited as a supplementary method for patients at day 5 or more after illness onset.

Laboratory-Enhanced Dengue Sentinel Surveillance in Colombo District, Sri Lanka: 2012-2014

“…Furthermore, the proportion of NS1 positive subjects in the first 5 days of illness was higher than that of PCR. Higher sensitivity of NS1 compared with PCR has been documented in some studies [ 22 – 24 ] but not in others[ 25 ]. It is important to note that we tested NS1 by ELISA and not with the cheaper rapid diagnostic (RDT) kits that are now widely available.…”

Clinical, hematological and serological profile in suspected dengue patients at IICS-UNA, 2009-2013

“…En el estudio de Chen y col. observaron que la sensibilidad de la IgM como marcador diagnóstico era baja en los primeros cuatro días de evolución de la enfermedad, pero aumentaba rápidamente de 65,4% (día 5) hasta 88,9% (>7 días) (23). Los títulos de anticuerpos IgM en infecciones primarias son significativamente mayores que en las secundarias; en las primarias, la IgM puede persistir por más de 90 días, aunque en la mayoría de los pacientes disminuye y ya no se puede detectar alrededor de los 60 días de la infección (17).…”

Laboratory and Molecular Characterization of Dengue Viruses in a 2014 Outbreak in Guangfo Region, Southern China

“…RNA extracts (5 µL) were amplified using the following cycling conditions: 50 C for 15 min and 95 C for 15 min, followed by 40 cycles of 94 C for 15 s and 55 C for 45 s. Based on the instructions for the test kit, samples with a threshold cycle (Ct) value ＜ 38.0 in the logarithmic phase of the amplification curve were defined as DENV-positive. Samples with a Ct value 38.0 or that did not show logarithmic amplification were defined as DENV-negative (27).…”