Page 138 - MNUmicrobiology practical 2025

General Microbiology & Immunology (PM 401) second level Semester 4 2024/2025

Indirect ELISA

• In this test an enzyme- labelled anti-human Ig is used to detect the presence of specific

Abs in patients’ sera.

• Known Ag is fixed by adsorption onto a plastic surface.

• The serum sample is added ( if specific Ab is present, it will bind the fixed Ag).
• Wash, Add the enzyme-labelled antihuman Ig

• wash the excess
• Add the substrate, then quantitatively measure for the degree of colour change.

General Microbiology & Immunology (PM 401) Practical note Page 127