This antibody is linked to an enzyme, and, in the final step, a substance containing the enzyme's substrate is added. The subsequent reaction produces a detectable signal, most commonly a color change in the substrate. Performing an ELISA involves at least one antibody with specificity for a particular antigen. substrate for the enzyme is applied, and catalysis by the enzyme leads to a change in color or fluorescence. ELISA results are reported as a number; the most controversial aspect of this test is determining the cut-off point between a positive and a negative result.
The University operates a two semester academic year with each semester running for approximately 13 teaching weeks followed by 2 weeks of examination. Semester I usually starts during the last week in August and ends late December. Semester II starts about late January and ends around mid May.
Each semester is about 4 months, usually from mid-January to  mid-May, and also from mid-August to mid-December. So both  semesters together are about eight months, plus thrâ¦ee months for  summer vacation, and about a month for winter vacation adds up to  twelve months.