 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.A positive apt test would mean that the blood is either due to gastrointestinal or pulmonary bleeding from the neonate.A negative Apt test would indicate that the blood is of maternal origin, suggesting that the neonate swallowed or aspirated maternal blood, either during delivery or during breastfeeding (e.g., from breast fissures).