How the SERATEC® HemDirect test work?

The test contains two monoclonal anti-hemoglobin antibodies as active compounds. One of the antibodies has been immobilized as line in the test result region (T) of the membrane. The other antibody is gold-labeled. It is placed downstream of the membrane on a glass fibre pad and becomes mobilized by the addition of the liquid. If hemoglobin is present in the sample it will bind to the gold-labeled antibody forming a complex. Through the capillary effect of the membrane, the liquid moves across the membrane towards the test result region. Here the immobilized antibody that recognizes another epitope of hemoglobin will bind the hemoglobin complexed with the gold labelled antibody (formation of a sandwich complex). This can be seen by the appearance of the red test result line.
The control line is composed of a different antibody pair (rabbit antibodies/goat anti-rabbit antibodies) one of which is immobilized at the control region. The other one is gold-labelled and mobile. As these antibodies interact directly with each other, the control line is formed independent of the presence of hemoglobin. The appearance of the control line serves as an internal control for the correct performance of the test.