Fetal and maternal blood can be differentiated by

Apt testKleihauer-Betke testSource of SampleMaternal or NeonatalMaternalPrincipleAdding 1% NaOH destroys adult HbA but not fetal HbFAdding acid destroys adult HbA but not fetalHbFAssessment TypeQualitativeQuantitativeResultPositive means blood is of fetal originRepoed in estimated milliliters of fetal bloodNote:When fetal blood needs to be differentiated from maternal bloodApt Test is used (Qualitative estimation)When the amount of fetal blood needs to be estimatedKleihauer-Betke test is used(Quantitative estimation)Approximate volume of fetal blood entering into the maternal circulation is to be estimated by Kleihauer-Betke test using acid elution technique to note the number of fetal red cells per 50 low power fields.If there are 80 fetal erythrocytes in 50 low power fields in maternal peripheral blood films, it represents a transplacental hemorrhage to the extent of 4ml of fetal blood.(Refer: Mudaliar and Menon&;s Clinical Obstetrics, 11th edition, pg no:227)