Test used to differentiate between maternal and fetal blood in a given sample

Ans. c. Apt test Both Apt test and Kleihauer-Betke test can be used to detect the presence of fetal blood within a sample but test used to differentiate between maternal and fetal blood in a given sample is Apt test. Apt Test: Used to detect the presence or absence of fetal blood (qualitative) in a vaginal discharge to rule out vasa pre late in pregnancy or to detect the origin of a neonatal bloody vomiting, whether it is a genuine upper GI hemorrhage/ hemoptysis or simply swallowed maternal blood during delivery or from cracked nipple. Kleihauer-Betke Test: The sample is maternal peripheral smear and is used to see how much of fetal blood (quantitative) has been transfused into the maternal serum in order to assess the risk of isoimmunization and then the risk of hemolytic disease of newborn. Both of them relies on the fact that HbF is resistant to alkali (Apt) and acids (Kleihauer-Betke) and so the HbA containing RBCs (Maternal) will be hemolyzed but not the fetal RBCs as they contain the HbF. When fetal blood needs to be differentiated from maternal blood Apt test is usedQ (Qualitative estimation) When the amount of fetal bleeding needs to be estimated Kleihauer-Betke test is usedQ (Quantitative estimation) Apt test Kleihauer-Betke test Source of sample Maternal or neonatal MaternalQ Principle Adding 1% NaOH destroys adult HbA but not fetal HbF Adding acid destroys adult HbA but not fetal Assessment Type QualitativeQ QuantitativeQ Result Positive means blood is of fetal origindeg Repoed in estimated milliliters of fetal