ELISA
ELISA is a lab test that uses color changes to find and measure tiny proteins in blood.
Think of it this way
A row of small cups sits on a tray. Each cup has a special coating that grabs one specific protein. You pour your sample in, and matching proteins stick to the walls. Then you add a dye — the more protein stuck, the darker the color gets.
Explaining elisa by grade level
Your body has tiny helpers in your blood. They are too small to see. A special test can find them. The test uses a plate with small wells. Each well catches one kind of helper. Then a dye is added. If the helper is there, the well changes color.