I found an article in CAP Today about the problems with Kleihaur Betke stain dose calculations. It had a reference for an electronic calculator for calculating the dose. You enter the patient's weight and height and the percent fetal cells and it calculates the number of vials of Rhogam. It is neat. I made it part of our procedure.
You can get it at: www.cap.org, under Committees and Leadership, Transfusion Medicine Resource Committee, Transfusion Medicine Topic Center.