Thimerosal dependent agglutination, a newly described blood bank problem.

A number of ABO grouping, Rh typing, antibody screening, and antibody identification problems are associated with chemicals in blood bank reagents. We describe a newly discovered agglutination phenomenon due to a thimerosal (Merthiolate)-dependent agglutinin found in the serum of a normal blood donor. Thimerosal is used as a preservative in several low-ionic strength reagents. This agglutination phenomenon is detected only in test systems (low-ionic-strength, albumin, saline, ficin treated test cells) in which test cells are incubated in the presence of thimerosal. Agglutination does not occur in the absence of thimerosal. The thimerosal-dependent agglutinin behaves like an IgG IgG autoantibody. There is no evidence that the thimerosal-dependent agglutinin is responsible for increased red cell destruction.