Detection of fetal hemorrhage in Rh immune globulin candidates. A rosetting technique using enzyme‐treated Rh2Rh2 indicator erythrocytes

Publisher Website
Google Scholar
Abstract
Current serologic tests may fail to identify women needing > 1 vial of Rh immune globulin. The indirect antiglobulin test after incubation with anti-D and a rosetting technique using enzyme treated Rh2Rh2 erythrocytes as methods for identifying significant fetal maternal hemorrhage (FMH) were compared. Artificial mixtures containing 0.05-1.2% Rh1rh (CcDe) fetal red blood cells mixed with rh (ce) adult red blood cells were tested. The indirect antiglobulin test of the 0.6% mixture (.apprxeq. 30 ml FMH) was reported microscopically positive by 17/20 technologists; 20/20 found the rosetting test strongly positive. The volume of FMH in 118 postpartum Rh immune globulin candidates was quantified using Kleihauer''s test and formula. The results of the rosetting and Kleihauer tests of blood specimens from these patients were as follows: negative rosetting and FMH of < 2 ml for 115 patients; rare agglutinates in the rosetting test and FMH of 1.4 ml for 2 patients; and strongly positive rosetting and FMH of 6.5 ml for 1 patient. The rosetting test uses routine blood banking skills and requires 5 min more hands on time than an indirect antiglobulin test. Confirmation and quantification of positive results by an acid-elution test are necessary.