[Use of Groupamatic in surveying fetomaternal alloimmunizations]

The A.V.I.S. Blood Transfusion Center of Turin performs the screening of foetomaternal allo-immunizations for the S. Anna Hospital of Turin. This hospital includes 3 hospital departments and 3 obstetrical and gynaecological university departments. The number of births in one year is roughly 13.000, i.e. 50 mother-baby couples, are tested every day. The identification system and the sampling process are described. The program used on the Groupamatic system includes: 1.) First run: Blood typing of mother blood with screening of alloantibodies. Second run: Blood typing control, screening of immune anti-A and anti-B antibodies, syphilis screening. 2.) Washing of cord blood red blood cells: First run: Washed red blood cells ABO and Rhesus typing, direct Coombs test. Second run: Blood typing control. Automatic screening of maternal irregular alloantibodies and automatic indirect Coombs test on washed cordblood red cells are simultaneously controlled with standard manual techniques. Sampling and testing are processed within 24 hours after birth. The set of results concerning mother-baby couples are grouped on one card and sent to the hospital department for a quick MHNN prophylaxy. Results of tests performed on 6.351 pregnancies studied until birth are presented. The automated direct Coombs test was positive with: 1--95% of new borns from mother who have a high immune allo antibody anti-A/B titer (IgG after treatment with two Mercapto etanol greater than I/64). 2--100% of new borns from mother who have irregular allo antibodies in Rh, Kell, Duffy or Kidd systems.