Spuriously Positive Direct Antiglobulin Tests Caused by Use of Silicone Gel

Abstract
The direct antiglobulin test using broad-spectrum antihuman globulin was spuriously positive for 8 subjects (13%) when red blood cells from silicone gel separation tubes were used. Serum separator tubes containing silicone gel apparently have limited use in the blood bank and transfusion service, especially when direct antiglobulin tests must be performed. The tests were positive with anti-C3 reagent, but were negative with anti-IgG when monospecific antihuman globulin was used.