Low ionic strength salt solution (LISS): Its effective use in routine compatibility testing

Abstract

A study comparing the LISS indirect antiglobulin technique with the conventional albumin-fortified method strongly indicated the superiority of the former test with regard to reaction velocity and sensitivity. It was also found that the LISS suspended cells could be used throughout the entire compatibility procedure, thus replacing saline as the conventional suspension medium. This slight change in protocol not only resulted in some increase in sensitivity but also reduced the potential errors which arose when different suspension media were used in routine testing procedures. Non-specific, false positive, reactions were not found to occur under routine test conditions. However, interference by cold agglutinins with the LISS papain and indirect antiglobulin procedures was found to occur in 2% of routine serum samples. In these, the variable masking reactions encountered were easily eliminated by performing the tests strictly at 37° and by using specific anti-IgG and anti-C4b, C3b in the indirect antiglobulin test. Over the last 3½ years, some 30,000 units have been compatibility-tested for routine and emergency blood transfusions using LISS suspended cells. No sero-positive red cell-induced transfusion reactions have been encountered during this time. In emergencies, compatibility-tested blood has been available within 30 min of receiving a fully clotted blood sample, thus making it rarely necessary to issue uncrossmatched blood. A study comparing the LISS indirect antiglobulin technique with the conventional albumin-fortified method strongly indicated the superiority of the former test with regard to reaction velocity and sensitivity. It was also found that the LISS suspended cells could be used throughout the entire compatibility procedure, thus replacing saline as the conventional suspension medium. This slight change in protocol not only resulted in some increase in sensitivity but also reduced the potential errors which arose when different suspension media were used in routine testing procedures. Non-specific, false positive, reactions were not found to occur under routine test conditions. However, interference by cold agglutinins with the LISS papain and indirect antiglobulin procedures was found to occur in 2% of routine serum samples. In these, the variable masking reactions encountered were easily eliminated by performing the tests strictly at 37° and by using specific anti-IgG and anti-C4b, C3b in the indirect antiglobulin test. Over the last 3½ years, some 30,000 units have been compatibility-tested for routine and emergency blood transfusions using LISS suspended cells. No sero-positive red cell-induced transfusion reactions have been encountered during this time. In emergencies, compatibility-tested blood has been available within 30 min of receiving a fully clotted blood sample, thus making it rarely necessary to issue uncrossmatched blood.