Radioimmunopreciptation assay: Is a sensitive test that find particular andtibodies in serum by using radiolabeled antigens. By using protein A sepharose beads(particular reagent) the antigen react with the serum. (3) Real time quaking-induced conversion (RT-QuIC): Is an advanced technique for detecting the prion protein in human serum and the study of misfolding disease  for instance  Alzheimer’s and Parkinson’s disease.  Is a rapid and sensitive protein detection teqnique.(4) One of the clinical uses of imunopreciptation is detect virus protein in some virus disease such as HIV type 1. Radioimmunopreciptation is a devoloped test of immnonopreciptation that is used to detect and determine antibodies of glycoproteirn gp 120 of the human immunodeficiency virus (HIV-1). The test, which used recombinant gp120 “was quantitative, reproducible, and specific for antibodies to rgp120 or antibodies to native gp120 resulting from natural infection with HIV“(Baxter CG,at al.2013). At a final concentration of 10% to accumulate immune complexes used Polyethylene glycol-8000 (PEG), and showed to be active in titering sera. (Baxter CG,at al.2013)The samples should be diluted minimum at 1:100, Classical dilution method or calibration curve prepared with a positive serum by interpolation can determine the  antibody titers. The reaction gained  in a commercial HIV immunoblot test is linked to raidoimmunoprciptation titers of human HIV sera. The advantages of the test is fast `turnaround`(Baxter CG,at al.2013) quantitative and `versatility`(Baxter CG,at al.2013).(Baxter CG,at al.2013)  Prion disease is a fetal neurodegenerative condition. Is linked to the brain which is form abnormal cellular protein form or ‘rogue’, which is called prion protein. This abnormality protein affect the shape of prion protein. The test detect the  protein in the plasma (component of blood) .(Christina D. Orrú,at al.2011). Despite blood contains inhibitor and  very low concentration of prion, so to seperate prions from inhibitors in plasma samples and raise sensitivity,  immunoprecipitation with quaking-induced conversion (QuIC) integrate antibody 15B3. Quaking-induced conversion can be as sensitive as in`vivo bioassays` but it is a very fast, higher production and does not  cost.(Christina D. Orrú,at al.2011).This test can detect prion from plasma sample on on 15B3 bead by  preincubation of the prion-bound beads for 20 minute at the rooom tempreture, Sarkosyl wash of the beads  and speed up prion amplification.(Christina D. Orrú,at al.2011).The combination of immunoprecipitation and  quaking-induced conversion(QuIC) significantly promote  detection of different brain tissue diluted into human plasma.(Christina D. Orrú,at al.2011).