[Usefulness of NaCl/Enzyme Gel Test for the Identification of Unexpected Antibodies.]

The microcolumn assay technique offers significant advances in identification of unexpected antibodies; however, some erythrocyte antibodies still remain unidentified. To see if NaCl/Enzyme test is useful for the identification of antibodies, we compared the LISS/Coombs and NaCl/Enzyme tests for identification rates, and investigated an association between the frequency of each antibody and a history of transfusion or gestation.

From June 2004 to June 2005, antibody screening tests were carried out on 5,517 patients using the LISS/Coombs gel test (DiaMed AG, Switzerland). When antibodies were detected, antibody identification tests were carried out with the LISS/Coombs and NaCl/Enzyme gel tests (DiaMed AG) simultaneously.

Unexpected antibodies were detected in 79 patients (1.43%). These antibodies were identified in 39 (49.4%), 59 (74.7%), and 68 patients (86.1%) by the LISS/Coombs test, the NaCl/Enzyme test, and the two tests combined, respectively. With the addition of the NaCl/ Enzyme test, unexpected antibodies were further identified in 29 cases (anti-Lewis, 14; anti-Rhesus, 13; and anti-P1, 2). On the other hand, 9 cases (anti-M, 5; anti-Fy(b), 3; and anti-N, 1) were identified by the LISS/Coombs test only. Of the unexpected antibodies found in patients without a previous history of transfusion or gestation, anti-Lewis (50.0%, 10/20) was the most common, while in patients with the history anti-Rhesus (48.1%, 26/54) was the most frequent.

The NaCl/Enzyme combined with LISS/Coombs gel test was useful for the identification of unexpected antibodies, and antibodies found in patients without a previous history of transfusion or gestation were clinically less relevant than those found in patients with the history.