الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
Abstract
Immunoassay methodologies represent the mostly used methods in the measurement of biological compounds in research and clinical investigations. RIA can be used for both the qualitative and quantitative measurements of a lot of small molecules as well as large peptides and proteins that are present in human body fluids and tissues. RIA provided a specific, rapid, sensitive, reliable, convenient, reproducible and less expensive assay technique.
This study was tackled the preparation, optimization, and evaluation of HBsAg RIA system. HBsAg was chosen because of its high importance in the diagnosis of HBV infections.
For preparing local liquid phase RIA technique, three components were prepared which are the polyclonal anti- HBsAg antibody, HBsAg iodine radiotracer, and HBsAg standards.
In the present study we used HBV positive blood sample to prepare purified HBsAg to be used for production of specific antibody to be used further in the diagnostic kits.
Then the prepared antigen was used for immunization to assess their antigenicity.
Preparation of HBsAg standards was undertaken to be used in both quantitative ELISA and RIA assays that used in the determination of unknown samples and the prepared antigen concentrations.
Production of polyclonal anti- HBsAg antibody was undertaken through immunization of 6 mature white New Zealand rabbits with three different HBsAg antigens. Then the produced antibodies were characterized in term of titer, displacement, immunoresponse, and potential sensitivity (affinity).
The radiotracer was prepared by direct labeling using chloramine-T oxidation method. Then the tracer was purified using gel filtration chromatography and its purity was assessed using TLC method.
For achieving reproducible and sensitive assay, studies on optimum sample volume, incubation time, incubation temperature, second antibody dilutions, NRS dilutions, and PEG concentrations were performed.
The optimized standard curve was then drawn from the optimization results which will be used later for the estimation of the unknown samples.
In order to validate the proposed assay, some performance characteristics were studied including sensitivity, precision, accuracy, cross reactivity, and method comparison.
The results of validation tests revealed that the proposed assay was with high sensitivity, high precision and accuracy with low coefficient of variation, without cross reactivity, and the method comparison results revealed strong positive correlation with the commercially available kits.
In conclusion, the technical simplicity of this sensitive, precise, and accurate method may suggest that this HBsAg -RIA technique should be suited for routine laboratory uses and can be used effectively as a diagnostic tool for diagnosing HBV infections.