An evaluation of a gel technique for antibody screening compared with a conventional tube method

Summary. An antihuman globulin (AHG) gel centrifugation technique (AHG gel test) employing microtubes (DiaMed®) has been compared for sensitivity in detection of unexpected antibodies with a saline indirect antiglobulin test (SIAT) which uses a cell‐to‐serum ratio between 1:120 and 1:200 and provides positive reactions at a concentration of a standard anti‐D of 2 ng/mL (0·01 IU/ml) or less. For most antibodies examined the AHG gel test was slightly less sensitive than the SIAT but both methods were capable of detecting anti‐D at concentrations of 2 ng/ml or less. The importance of defining in detail the conventional tube test method used in such evaluations is emphasized since previous reports of sensitivity of the DiaMed AHG gel test indicate considerable variation in technique and comparative sensitivity.