Wantai Hepatitis E Virus Diagnostic Kits



Hepatitis E , which was previously called enterically transmitted non-A non-B hepatitis, is caused by infection with hepatitis E virus (HEV), a RNA virus that is still not classified. The first experimental evidence for the existence of HEV was reported by Balayan, who observed viral particles in size of 27-38nm isolated from the stool of infected individuals.HEV is transmitted through the fecal-oral route, predominately through contaminated water or food supplies. Sporadic outbreaks of hepatitis E have been reported in developing countries.
The disease progression of Hepatitis E is similar to infection with Hepatitis A. However, severe form of hepatitis is easier to develop, especially when the individual is super-infected with another hepatitis viruses. The overall mortality ranges from 0.5% - 4.0% and may reach a rate of 20% among pregnant women during the 3rd trimester of pregnancy.
Wantai HEV ELISA kits use a recombinant capsid Ag (E2) expressed from highly conserved region of ORF2 of the HEV.This Ag expresses some important conformation Antigenic epitopes of the native virus and shows extremely high reactivity to HEV specific antibodies . The ORF -2 region in the HEV can dimerize with an increasing reactivity in HEV convalescence sera. Wantai ELISA kits are based on the use of these dimers which have shown an improved sensitivity as compared to other ELISA s (lower limit of detection for HEV IgG is 0.25 WHO units/ml and showed higher positively in sera from proven cases i.e. 98 % and also remained positive for a longer post – infection period).

Comparison study between Wantai HEV-IgM ELISA and two other commercial tests for detection of HEV.


Reagents Acute Hepatitis E Healthy individuals Overall agreement
Positive/ tested Sensitivity Negative/ tested Specificity
Wantai HEV-IgM 47 / 48 97.9% 273 / 273 100% 97.9%
HEV ELISA 1 35 / 48 72.9% 264 / 273 96.7% 69.6%
HEV ELISA 2 45 / 48 93.8% 233 / 273 85.3% 79.1%

HEV-IgM ELISA

Among study group of 16865 individuals, (including 7113 blood donors), the specificity of Wantai HEV-IgM is 98.8%. In testing of acute hepatitis A, B and C sera, the overall specificity is 95.3%.

Performance
Sensitivity 100% , 20mlU/ml
Specificity > 97%
Cross reactions None
Features
Test principle Antibody “capture” ELISA
Total incubation time 30 min + 30 min + 15 min

HEV-IgG ELISA

Samples from 50 cases diagnosed positive during the Xinjiang hepatitis E outbreak in 1986 (>10 years post infection), were tested with Wantai HEV-IgG ELISA. The detection rate of the test within this study group is 86%.

Positive sera OD
Reagents Samples Pos. Sens. MIN AVER. MAX Positive sera average s/co
Wantai HEV-IgG 50 43 86% 0.532 1.368 2.327 9.24
HEV ELISA 1 50 18 36.0% 0.514 1.018 2.415 1.98
HEV ELISA 2 50 15 30% 0.229 0.457 1.094 2.08

Multi-centre sensitivity evaluation study with Wantai HEV IgG ELISA. Demonstrated overall detection rate of >99%.

Performance
Sensitivity 100% , 20mlU/ml
Specificity > 99%
Cross reactions None
Features
Test principle Indirect ELISA
Total incubation time 30 min + 30 min + 15 min
CE Marked

HEV Ag ELISA

Features
Sample dilution 100 ul nos sample dilution
Test principle Double Ab Sandwich ELISA
Total incubation time 60min. + 30 min. + 30 min.
CE Marked

HEV IgM based on Mu Capture principle.