A Sabin–Feldman dye test is a serologic test to diagnose for toxoplasmosis. The test is based on the presence of certain antibodies that prevent methylene blue dye from entering the cytoplasm of Toxoplasma organisms. Patient serum is treated with Toxoplasma trophozoites and complements as activator, and then incubated. After incubation, methylene blue is added. If anti-Toxo antibodies are present in the serum, becasue these antibodies are activated by complements and lyse the parasite membrane, Toxoplasma trophozoites are not stained (positive result); if there are no antibodies, trophozoites with intact membrane are stained and appear blue under microscope (negative result)
Famous quotes containing the words dye and/or test:
“It will help me nothing
To plead mine innocence, for that dye is on me
Which makes my whit’st part black.”
—William Shakespeare (1564–1616)
“It is the test of a novel writer’s art that he conceal his snake-in-the-grass; but the reader may be sure that it is always there.”
—Anthony Trollope (1815–1882)