Msl934006 Apply Quality System And Assessment Answer

1. Create an SOP for using a common laboratory technique or method. (eg: gram staining, using a balance, using a microscope, using a graticule and micrometre) Make sure you follow the document control measures from the theory slides for SOP documents. 2. Using the information below find the important points and develop a Quick Reference Guide or poster. “After the incubation the slides are washed to remove any of the antibodies that have not reacted with the antigen. The next step is to add the biotin-labelled secondary antibody this will bind with the antigen antibody reaction that has already taken place. After the incubation the slides are washed to remove any excess secondary antibody that has not bound to the antigen antibody reaction. The next step is to incubate the slides with Streptavidin-HRP this reacts with the biotin on the secondary antibody, which is specifically bound to the primary antibody. The slides are the washed again only in buffer this time to remove any excess enzyme. The HRP component of the Streptavidin –HRP is an enzyme that can catalyse a substrate/chromogen. The chromogen that is used in this kit is 3, 3 diaminobenzidine diluted in TBS is mixed with hydrogen peroxide diluted in TBS, and this is mixed together fresh to make the substrate / chromogen call (DAB). The DAB reacts with the HRP enzyme to form a coloured molecule and HRP and water. After the reaction has taken place the slides are washed with water to prevent background and over staining with the DAB. The reaction results in a brown/ black deposit at the chosen antigenic site. DAB is considered to be a carcinogen see safety aspect below for the handling of this material. There are other chromogens that can be used for this method but the brown is the one of choice for our laboratory. The next step is to stain the structures that have not had primary antibody bind to them. The counterstain of choice is Harris Haematoxylin; this will give the tissue a purple appearance. To give the stain better contrast it is blued in ammonia water, making them bluer. The result will be that the positive cells for the antibody tested will be brown and the negative cells will be blue.”