The fetomaternal bleed test identifies cells containing fetal hemoglobin. The cells are fixed and permeabilized and then incubated with monoclonal antibodies directed against fetal hemoglobin (HbF) and subsequently analyzed by flow cytometric methods. This test uses the FDA-approved Invitrogen Fetal Hemoglobin kit with fluorescein isothiocyanate-conjugated monoclonal antibody directed to HbF (HFH-10).(Package insert: Life Technologies Corporation, MAN 0003641, Rev 2.00 effective date March 16, 2012)
RhIG dose calculation: mL of fetal bleed/15 = calculated doses of RhIG, then add a safety margin, ie, when the number to the right of the decimal point is less than 5, round down and add 1 dose (example: 2.2 = 2.0 + 1 = 3); when the number to the right of the decimal point is 5 or greater, round up to the next number and add 1 dose (example: 2.8 = 3.0 + 1 = 4). If fetal bleed is < or =1.5 mL it will be reported as negative bleed and the RhIG dose will be 1.