Detection of Rh antibodies using two low ionic diluents: extension of the incubation time and the number of Rh antibodies detected.

BACKGROUND: Low ionic strength solution (LISS) is used to increase the rate of association of antibody to the corresponding antigen during antibody detection tests. A number of LISSs are available on the market. AIMS: The efficiency of two commercial low ionic diluents, DiaMed ID-CellStab and Inverclyde LISS were assessed using the DiaMed-ID LISS Coombs microtube column system and an incubation time varying from 15 to 35 min. MATERIALS AND METHODS: One-hundred samples containing five Rh antibodies (anti-D, anti-C, anti-E, anti-c and anti-e) were tested against commercial red cells using the two low ionic diluents after 15, 25 and 35 min. RESULTS: The Inverclyde LISS detected 91, 95 and 96% of the Rh antibodies compared to 78, 79 and 83% for ID-CellStab after 15, 25 and 35 min incubation time, respectively, for both methods. CONCLUSIONS: The Inverclyde LISS is a more suitable and efficient diluent than ID-CellStab for the detection of Rh antibodies. The sensitivity of Rh antibody detection increased for the both methods as the incubation time increased.

Detection of red cell antibodies: comparison of two low ionic strength diluents.

Various low ionic strength diluents are used routinely for red cell alloantibody detection in the antiglobulin test to increase the rate of antibody association to antigen, thereby allowing a reduction in the incubation time while achieving optimal agglutination. Two commercial low ionic strength diluents (DiaMed ID-CellStab and Inverclyde LISS) were assessed using the DiaMed-ID LISS Coombs' microtube column system, to assess whether or not the choice of diluent influences red cell antibody detection. Effects of two low ionic strength diluents after 15-min incubation were assessed in 150 samples containing a wide range of typical red cell alloantibodies. Inverclyde LISS gave significantly higher reaction strengths in 25% of samples when compared with the same red cells suspended in ID-CellStab. Variation in reaction strengths ranged from 1+ to 2+, using Inverclyde LISS versus CellStab. Of 131 red cell alloantibodies directed against Rh, Kell, Kidd and Duffy antigens, Inverclyde LISS detected 90% after 15-min incubation, whereas 83% were detected with CellStab. This study suggests that Inverclyde LISS provides better red cell alloantibody detection than does ID-CellStab, and this may be due to the higher ionic strength of ID-CellStab.