In an immunodiffusion test to diagnose histoplasmosis, a patientʹs serum is placed in a well in an agar plate. In a positive test, a line forms as the serum diffuses from the well and meets material diffusing from a second well. What type of test is this?
A) a precipitation reaction
B) a direct ELISA test
C) a complement-fixation test
D) an agglutination reaction
E) an indirect ELISA test

Question

Quizplus · Accepted Answer

This test is a precipitation reaction, where soluble antigens and antibodies diffuse towards each other in an agar medium and form a visible line of precipitation when they meet and react.

In an Immunodiffusion Test to Diagnose Histoplasmosis, a Patientʹs Serum