 The Apt test can also be used to detect the presence of fetal blood in the maternal circulation in cases of suspected fetal-maternal hemorrhage.Since the test is only a qualitative determination of the presence of fetal hemoglobin in maternal blood, the quantitative Kleihauer-Betke test is more commonly used.Finally, the Apt test can be used after birth (postpartum hemorrhage) if the newborn has bloody vomiting, bloody stool, or active bleeding from the nasogastric tube.