Sabin Feldman dye test is used for diagnosis of which of the following condition:

Ans. b. ToxoplasmosisRef: Diagnosis & Treatment of Uveitis by C Stephen Foster; Page No- 555 & Oskis Pediatrics: Principles & Practice edited by Julia A. McMillan; Page No-1356The Sabin Feldman dye test is the gold standard to which all serologic tests performed to detect anti-T. gondii antibodies are compared.It is a neutralization test in which the patients serum is incubated with complement and live Toxoplasma organisms, and a dye is employed to quantify the bound antibody.It allows early detection of the infection and has high sensitivity and specificity in both acute and chronic phases.This test makes use of the uptake by Toxoplasma tachyzoites of the dye methylene blue (in which organisms appear swollen and blue). The tachyzoites membranes lyse in the presence of complement and specific antibody (Primarily IgG) resulting thin, unstained-appearing organisms.This test has been used extensively as a screening test for toxoplasma infection; it has been recommended as the test of choice for antenatal maternal screening, but it is available only in reference laboratories.However, it is no longer used because it requires maintenance of live virulent parasites in the laboratory, and equally good, safer methods have been developed. Currently, the Sabin Feldman dye test is restricted to research centers as a method to standardize new tests.