Comparison of tube and gel techniques for antibody identification

There are several methods for antibody detection and each technique has advantages and limitations. We compared the performance of the tube (polyethylene glycol-indirect antiglobulin test [PEG-IAT]) and gel test technique for antibody identification. From January to May 1999, we performed antibody screening tests by gel and tube techniques on 10,123 random blood samples submitted to our reference laboratory. Six hundred and twenty-eight (6.2%) reactive samples were tested for antibody specificity by both methods. One hundred and ninety-six were reactive only by gel: 25 anti-D, 33 anti-C, 76 anti-E, 13 anti-c, 5 anti-e, 18 anti-K, 7 anti-Jka, 2 anti-Dia, 3 anti-S, 8 combination Rh antibodies (1 with anti- K), and 6 other antibody specificities. Two samples were reactive only by PEG-IAT: 1 anti-K and 1 anti-Dia. Four hundred and thirty were positive by the two methods: 156 anti-D, 9 anti-C, 68 anti-E, 15 anti-c, 6 anti-e, 61 anti-K, 12 anti-Jka, 17 anti-Dia, 5 anti-S, 73 combination Rh antibodies (2 with anti-K), and 8 other antibody specificities. Based on this study, the gel test is more sensitive (p <.01) than the tube test for identifying potentially clinically significant antibodies.