Evaluation on the analytical sensitivity of 31 HBsAg enzyme immunoassay kits / 中华流行病学杂志

Objective To study the analytical sensitivity on 31 HBsAg enzyme immunoassy (EIA) test kits.Methotis Thirty one HBsAg EIA kits produced by domestic or overseas manufactories and applied for approval during May 2007 to May 2008,were evaluated using the national reference panels.The hyperbolic curve of the log A value and log concentration for the national sensitivity standards was established.The cut-off value of each kit was substituted into the curvilinear equation to determine the analytical sensitivity which was compared between different HBsAg EIA kits.Results Twenty seven(351 lots) domestic and 4(27 lots) overseas kits were compared.Among 378 lots of the 31 HBsAg EIA kits,only 2 lots of the domestic kits had a lower sensitivity when tested with the national HBsAg reference panels,with an average approvalr ate of 99.43%(349/351).The mean analytical sensitivity of the domestic kits for adr,adw,ay serotypes were 0.307,0.419,0.513 ng/ml,respectively.There was a significant difierence between serotypes (F=97.30,P<0.01).The mean analytical sensitivity of the overseas kits for adr,adw,ay serotypes were 0.054,0.066,0.050 ng/ml respectively,with no significant difference between serotypes(F=0.65,P>0.05).The analytical sensitivity of the overseas kits for all the three serotypes was higher than that of the domestic kits(P<0.01).There was no significant difference found between the analytical sensitivities of the kits produced by the same manufactory using 30- or 60- minute incubation of detection(P>0.05).In contrast,there was significant diffefence noticed between the analytical sensitivities of the kits produced by the same manufactory when tested for 10 or 15- minute coloration of the results(P<0.01).Conclusion Analytical sensitivity of the HBsAg EIA domestic kits should be further improved,especiatry for detecting adw and ay serotypes.

Evaluation of multiplex nucleic acid testing assays for screening of hepatitis B virus DNA in blood donation process / 中华流行病学杂志

Objective To evaluate the multiplex nucleic acid testing (NAT) assays for HBV,HCV and HIV in detecting HBV DNA in plasma samples. Methods 534 plasma samples collected form several areas were detected with Abbott Architect i2000 HBsAg, ani-HBs, HBeAg, anti-HBe, anti-HBc and anti-HBc IgM diagnostic kits. HBV DNA levels of those samples were detected with Roche COBAS AmpliPrep/ COBAS TaqMan HBV Test. Two kinds of multiplex NAT assays for HBV, HCV and HIV were used to test HBV DNA of those 534 samples. Results of serology-markers and quantitative HBV DNA levels with results of NAT were compared. Results HBV DNA was positive in all 81 HBsAg, HBeAg and anti-HBc positive samples,detected by both of NAT assays. HBV DNA was positive in 11 and 19 of 200 HBsAg negative samples when detected with the two kinds of NAT assays separately. Compared with the quantitative results detected by Roche COBAS AmpliPrep/COBAS TaqMan HBV Test, the HBV DNA positive rates were 96.9% and 94.3% in 193 samples of HBV DNA levels over 500 IU/ml while 40.2% and 45.3% in 117 samples of HBV DNA levels below 500 IU/ml while 99.3% and 96.0% in 151 samples of DNA negative HBV. Conclusion There are some occult low level HBV DNA carriers with HBsAg negative results in China. NAT assays for HBV, HCV and HIV may be useful to improve the transfusion safety.

Primary evaluation of anti-HEV diagnostic reagent by experimental infection animal model with hepatitis E virus / 中华流行病学杂志

<p><b>OBJECTIVE</b>To evaluate anti-HEV diagnostic kits by experimental infecting rhesus monkeys with HEV.</p><p><b>METHODS</b>Eight rhesus monkeys were infected with genotype 1 and 4 HEV separately. The alanine aminotransferase (ALT) level of all monkeys were detected before and after the process of infection. HEV RNA in stool specimens was tested by reverse transcriptase-polymerase chain reaction (RT-PCR) assay. Anti-HEV IgG in serum was detected by GL-IgG and WT-IgG.</p><p><b>RESULTS</b>HEV RNA presented in the stool of all the 8 monkeys after infection. The ALT level of 1 monkey infected with genotype 1 HEV and 2 monkeys infected with genotype 4 HEV appeared abnormally after infection. Tested by GL-IgG, 2 of the 4 monkeys infected with genotype 1 HEV and 1 of 4 monkeys infected with genotype 4 HEV seroconverted to anti-HEV IgG. However, when tested by WT-IgG, all the infected monkeys seroconverted to anti-HEV IgG. The anti-HEV IgG tested by WT-IgG was positive during the whole observation period,and the anti-HEV IgG measured by GL-IgG only remained 12 weeks after infection. Detected by GL-IgG and WT-IgG, seropositive conversion of the anti-HEV IgG happened almost at the same time.</p><p><b>CONCLUSION</b>Both GL-IgG and WT-IgG could detect the anti-HEV IgG of experimentally infected rhesus monkeys but the WT-IgG had a higher sensitivity for detection of anti-HEV IgG than</p>

Clinical significance of detecting RNA and anti HEV antibody in convalesent sera in patients with acute HEV hepatitis / 中华实验和临床病毒学杂志

<p><b>OBJECTIVE</b>To investigate the anti hepatitis E virus (HEV) and HEV RNA in acute and convalescent sera of patients with NonA-E acute hepatitis.</p><p><b>METHODS</b>The serum samples were taken from 95 patients who were diagnosed as acute NonA-E hepatitis. Enzyme immunoassay (EIA) was used for detecting anti-HEV Immunoglobulin G (IgG, Genolable and Wantai EIA anti-HEV kits). RT-PCR amplification of HEV RNA was based on the open reading frame 2 region of HEV and the PCR products were sequenced.</p><p><b>RESULTS</b>Sera from 95 patients who were negative for anti-HEV in acute phase were followed up for 11-35 days to detect the anti-HEV antibody in recovery phase, 16/95 (16.84%) were positive for anti-HEV (wantai EIA anti-HEV kits). Ten (62.50%) were positive for HEV RNA in acute phase. Sequence analysis showed that 4 were HEV genotype. 6 were HEV genotype; 12/95 (12.50%) were positive for anti-HEV (Genolable EIA anti-HEV kits). Seven were positive for HEV RNA; 4 belonged to HEV genotype, 3 were HEV genotype.</p><p><b>CONCLUSION</b>It is significant and necessary to detect anti HEV antibody and HEV RNA in patients with HEV infection during acute phase and convalesent phase.</p>

Preparation and application of the national reference panel for hepatitis B virus DNA / 中华肝脏病杂志

<p><b>OBJECTIVES</b>To calibrate the national hepatitis B virus (HBV) DNA standard according to world health organization's standard material and prepare the national reference panel for HBV DNA reagents.</p><p><b>METHODS</b>Sera from blood donors and HBV patients were collected and detected by home-made HBV DNA PCR kits, HBsAg kits, and anti-HBc kits, and then confirmed by HBV DNA PCR kits produced by Roche in German, which was recognized by the world health organization. The stability of the panel was detected by acceleration method.</p><p><b>RESULTS</b>The convinced copies of the sensitivity samples were gotten by seven independent experiments, the coefficients of variation of logarithm of the copies of L0-L5 were all less than 15%. Regarding the national reference panel as the standard, the quality of most domestic HBV DNA PCR kits was improved, while part of the kits should be further qualified.</p><p><b>CONCLUSION</b>The national reference panel for HBV DNA reagents is developed. It contains eight negative, nine positive sera and seven samples for sensitivity test</p>