Method Description

The immunodiffusion (ID) test is a qualitative test employed for the detection of precipitating antibodies present in the serum. Soluble antigens of the fungus are placed in wells of an agarose gel-filled Petri dish and the patient's serum and a control (positive) serum are placed in adjoining wells. If present, specific precipitate antibody will form precipitin lines between the wells. Their comparison to the control serum establishes the results. When performing the ID test, only precipitin bands of identity with the reference bands are significant.(Kaufman L, Kovacs JA, Reiss E: Clinical immunomycology. In: Rose NL, Conway-de Macario E, Folds JD, Lane HC, Nakamura RM, eds. Manual of Clinical Laboratory Immunology. ASM Press; 1997:587-588; Kaufman L, McLaughlin DW, Clark MJ, Blumer S: Specific immunodiffusion test for blastomycosis. Appl Microbiol. 1973;26:244-247; Williams JE, Murphy R, Standard PG, Phair JP: Serologic response in blastomycosis: diagnostic value of double immunodiffusion assay. Am Rev Resp Dis. 1981;123:209-212; Bennett JE, Dolin R, Blaser MJ, eds. Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases. 9th ed. Elsevier; 2020)