Zhigang Hu

Nanjing Medical University, Nan-ching, Jiangsu Sheng, China

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Publications (6)6.3 Total impact

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    ABSTRACT: The anticardiolipin antibodies (aCL) test has become a laboratory standard for the clinical diagnosis of antiphospholipid syndrome (APS). To better the quantitative detection of aCL-IgM so as to classify patients correctly and timely as APS positive, we established herein a new immunoassay based on a time-resolved fluoroimmunoassay (TRFIA). The complex of cardiolipin plus bovine anti-β2 glycoprotein-I was used as antigen fixed on microtiter plates to detect serum aCL-IgM, and Eu(3+) -labeled rabbit antihuman IgM was used as conjugate. The precision, sensitivity, specificity, coefficient of recovery, and stability of the assay were evaluated, and comparison with the traditional, classical enzyme-linked immunosorbent assay (ELISA) was also made. The detection limit of the aCL-IgM TRFIA kit we established was 0.1 MPL U/ml, with a wider detectable range than commercial ELISA ones when a strong-positive specimen was diluted from 2,630.9 to 0.08 MPL U/ml. There was a good liner range within 0.16 to 2,630.9 MPL U/ml, whereas it was within 5.14 to 328.86 MPL U/ml when using three commercial ELISA ones. The average intra- and interassay variability was 3.19 and 3.70%, respectively. The mean recovery rate was 101.95%. The clinical diagnostic specificity was 98%. Additionally, the established assay kit presented good characteristics of stability and correlated well with the ELISA, and the correlation coefficient was 0.955. The aCL-IgM TRFIA provides an approach to a more sensitive and reliable diagnosis of APS. Further validation of its use is required.
    Journal of Clinical Laboratory Analysis 03/2014; · 1.36 Impact Factor
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    ABSTRACT: In an effort to enhance the linear range of anti-CCP we developed a new immunoassay based on time-resolved fluoroimmunoassay. The precision, sensitivity, specificity, and stability of the assay were evaluated ELISA set as control. The anti-CCP IgG TRFIA kit we established had a wider detectable range than commercial ELISA ones. With regard to intra- and inter-assay precision, the TRFIA kit was better than threee commercial ELISA ones. The mean recovery rate was 101.0%. The TRFIA we developed for anti-CCP IgG detection yielded a more sensitive and reliable method for RA diagnosis and large-scale screening programs as well.
    Journal of Immunoassay and Immunochemistry 01/2014; 35(3):221-32. · 0.73 Impact Factor
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    ABSTRACT: In an effort to improve the quantitative detection of aCL IgM, we develop a new immunoassay to improve aCL IgM detection based on TRFIA using the complex of cardiolipin plus bovine β2GPI as antigen and Sm(3+)-labeled rabbit anti-human IgM as conjugate. The precision, sensitivity, specificity, coefficient of recovery, and stability of the assay were evaluated and comparison with the classical ELISA was also made. The aCL IgM TRFIA kit we established had a wider detectable range than commercial ELISA ones when diluted a specimen with strong positive from 1:2.5-1:40960. We observed that for the established TRFIA kit there was a good liner range within 1:2.5-1:40960, whereas it was within 1:20-1:1280 when using ELISA kits. The intraassay precision rate and the interassay precision rate were <5% for 3 different concentrations. The sensitivity was 0.1MPL U/mL and the clinical diagnostic specificity was 98%. Average recovery rate was 101.13%. The established assay kit also behaved better in stability. Additionally, the immunoassay we established correlated well with the ELISA and the correlation coefficient was 0.956. We thus conclude that the TRFIA we developed for aCL IgM detection gives promise to a more sensitivity and reliable diagnosis of APS and has potential value for large-scale screening programs.
    Journal of Immunoassay and Immunochemistry 07/2013; 34(3):255-65. · 0.73 Impact Factor
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    ABSTRACT: We demonstrate herein a novel time-resolved fluoroimmunoassay (TRFIA) with high sensitivity and wide range for quantitative detection of ANA-Ig(GAM) antibodies using a biotin-avidin amplification system. The immunoassay was conducted by following procedures for a typical sandwich immunoreactions with cell nucleus form Hela and the Eu(3+)-labeled biotin combined with biotinylated mouse anti-human Ig(GAM) served as the solid nuclear antigen for ANA and the tracer, respectively. The sensitivity, specificity, and stability of the kit were evaluated and comparison with the classical enzyme-linked immunosorbent assay (ELISA) kit was also made. The average intra-assay and interassay CVs detected by the established ANA-Ig(GAM) biotin-avidin-TRFIA were 4.21% and 6.34%, respectively. The lower detection limit was 2.24 U/mL, and the mean recovery rate was 100.74%. The good measurable range of the established biotin-avidin-TRFIA was within 1.95-64,000 U/mL, while it was only within 32.5-4000 U/mL using an ELISA kit. The values determined by the biotin-avidin-TRFIA and ELISA correlated well (R2 = 0.989). The positive rate of healthy volunteers and patients with systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), primary biliary cirrhosis (PBC), Sjögren's syndrome (SS), scleroderma, and mixed connective tissue disease (MCTD) was 0, 100%, 18.5%, 100%, 37.9%, 90.9%, and 92%, respectively. We conclude that the biotin-avidin-TRFIA we developed gives promise for greater sensitivity and accurate detection for ANA-Ig(GAM) in diagnosing and monitoring autoimmune disorders.
    Journal of Immunoassay and Immunochemistry 04/2013; 34(2):197-207. · 0.73 Impact Factor
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    ABSTRACT: In an effort to improve the quantitative detection of anticardiolipin antibodies (aCL) IgG so as to classify patients correctly as antiphospholipid syndrome (APS) positive, we developed a new immunoassay based on a sandwich time-resolved fluoroimmunoassay (TRFIA) using the complex of cardiolipin plus bovine β(2)GPI as antigen and Eu(3+)-labeled rabbit antihuman IgG as conjugate. The precision, sensitivity, specificity, and stability of the assay were evaluated, and comparison with the classical ELISA was also made. The aCL IgG TRFIA kit we established had a wider detectable range than three commercial ELISA ones from different manufacturers when a specimen was diluted, with strong positive result from 1:12.5 to 1:204,800. The average intra-assay and inter-assay CVs detected by the aCL IgG TRFIA was 3.14 and 3.70 %, respectively. The sensitivity was 0.1 GPL U/ml, and the clinical diagnostic specificity was 98 %. The established assay kit also behaved better in stability than the commercial ELISA ones. Additionally, the immunoassay we established correlated well with the ELISA, and the correlation coefficient was 0.975. We thus conclude that the TRFIA we developed for aCL IgG detection gives promise to a more sensitive and reliable diagnosis of APS and has potential value for large-scale screening programs.
    Clinical Rheumatology 06/2012; 31(9):1339-45. · 2.04 Impact Factor
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    ABSTRACT: The hepatitis B virus (HBV) PreS1 antigen is expressed at the distal most region of the envelope protein and contains the hepatocyte receptor-binding site. The presence of the HBV PreS1 antigen in serum and liver of HBsAg-positive patients is a new marker used for diagnosing HBV infection, and is indicative of viral replication. Our objective is to establish a method of time-resolved fluoroimmunoassay (TRFIA) with higher sensitivity and broader detection range for detecting serum HBV PreS1 antigen. Eu(3+) labeling of antibodies was performed with respective labeling kits, and Eu(3+) fluorescence intensity was measured with an auto DELFIA1235 TRFIA analyzer. The established method was evaluated for its performance. Serum specimens (574 in total) from Wuxi People's Hospital were analyzed for PreS1 antigen using the TRFIA and ELISA. The precision, specificity, and sensitivity of the TRFIA were clearly better than ELISA. The detection limit was 0.01 ng/mL. The average recovery rate for PreS1 antigens was 103.3%. There was significant correlation between the PreS1 antigen results obtained by TRFIA and ELISA in 374 serum samples with HBV >10(3) IU/mL (χ(2) = 25.04, p < 0.01) and 183 HbeAg-positive serum samples (χ(2) = 12.07, p < 0.01). Normal reference ranges were established at 0-0.32 ng/mL based on the values obtained from 100 healthy controls. TRFIA is a significantly effective method for clinical detection of serum HBV PreS1 antigens.
    Journal of Immunoassay and Immunochemistry 04/2012; 33(2):156-65. · 0.73 Impact Factor