Original Article
Comparison and evaluation of laboratory test techniques for severe fever with thrombocytopenia syndrome
Xiaolin Jiang, Xiaomei Zhang, Bo Pang, Dapeng Sun, Xianjun Wang, Shujun Ding
Published 2018-02-28
Cite as Chinese J Exp Clin Virol, 2018, 32(1): 38-42. DOI: 10.3760/cma.j.issn.1003-9279.2018.01.008
Abstract
ObjectiveCompare the detection result of blood samples of severe fever with thrombocytopenia syndrome (SFTS) patients using different detection techniques, and observe the dynamic characteristics of the virus specific RNA, IgM antibody and IgG antibody, to provide theoretical basis for selection of diagnostic methods of disease.
MethodsAcute phase serum of suspected SFTS cases and convalescent serum samples of lab-confirmed cases were collected. Real-time fluorescence quantitative PCR and enzyme-linked immunosorbent assay (ELISA) were used to detect the virus specific RNA, IgM antibody and IgG antibody. The detection results of different methods, the relationship between positive results and the acquisition time, and the dynamic characteristics of viral nucleic acid and antibodies were analyzed.
ResultsA total of 87 serum samples of the suspected SFTS patients were collected, the positive rate of virus specific RNA, IgM antibody and IgG antibody were 53.41%, 31.03% and 3.41%, respectively. Among 55 confirmed cases of SFTS, the consistent rate of virus specific RNA and IgM antibody detection methods was 36.36%, and the difference between the two methods was significant (χ2=6.82, P=0.009), kappa=-0.257. The sampling intervals of RNA positive samples were all within 12 days, of which the positive detection rate was highest after 7-9 days, and the difference was statistically significant (χ2=10.35, P=0.016). In 34 SFTS convalescent serum samples, all the nucleic acid tests were negative, the positive rate of IgM antibody was 41.18%, which was not significantly different from the acute phase serum samples (P=1.00). The positive rate of IgG antibody was 94.12%, which was significantly higher than that of acute IgG antibody (0%). The dynamic characteristics of IgM and IgG antibody showed that IgM antibody could be detected on the second day after onset, the latest detection time was 74 days after onset, and the highest absorbance value and antibody detection rate occurred in 30-60 days. The earliest detection time of IgG antibody was 12 days after onset, and the last detection time was 100 days.The detection rate of IgG antibody and absorbance value increased rapidly after 30 days, and maintained in a high level. The detection rate of IgG antibody was 100% in 30-60 days.
ConclusionsBlood samples taken from SFTS suspected patients within two weeks of onset may be prioritized for detection of viral nucleic acids using Real-time fluorescence PCR or for detection of IgM antibodies by ELISA. Although IgM antibody can be detected 2 days after the onset, the peak appeared much later, so the negative result can’t rule out the diagnosis. IgG antibody has a high seroconversion rate in convalescent samples, and can be used as an auxiliary tool for disease diagnosis.
Key words:
Severe fever with thrombocytopenia syndrome; SFTS virus; Nucleic acids; Antibodies; Real-time fluorescent quantitative PCR; Enzyme-linked immunosorbent assay
Contributor Information
Xiaolin Jiang
Department of Viral Disease Control and Prevention, Shandong Provincial Center for Disease Control and Prevention, Jinan 250014, China
Xiaomei Zhang
Bo Pang
Dapeng Sun
Xianjun Wang
Shujun Ding
