The Preparation and Use of Formalinized Erythrocytes with Attached Antigens or Haptens to Titrate Antibodies

1) Improved methods for preparation of formalinized red blood cells and a simple method using formalin to bind proteins to these cells yielding a stable, highly sensitive antigen have been described. 2) Cells prepared by these methods give agglutination patterns almost as distinct as those obtained using fresh cells, they are not agglutinated by traces of formaldehyde and are stable on storage at 3–5° C. 3) When cells were coupled with sulfanil-azo-groups a convenient and sensitive antigen for the estimation of antibody against this hapten was obtained.