Streptavidin is a complex molecular derived from Streptomyces avidinii which is used in a number of antibody-based assays. Antibody to streptavidin can cause a false-positive assay, which can result in misdiagnosis.
Features of anti-streptavidin antibody:
(1) A patient has a false-positive test.
(2) The test uses streptavidin.
(3) Testing for heterophile or other anti-species antibodies is negative.
(4) The patient has evidence of anti-streptavidin antibody:
(4a) There is evidence of an immunoglobulin in the serum against streptavidin.
(4b) Retesting the serum after absorbing out anti-streptavidin antibody (passing it through streptavidin-linked agarose or treating with streptavidin coated microparticles) gives a correct result.
(4c) Testing in a system without streptavidin gives a correct result.
(5) There are no other explanations that can explain the findings better.
Keys to diagnosis:
(1) realizing that the test result is incorrect
(2) thinking of anti-streptavidin antibody as a possible explanation
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