Internal Medicine Coding Alert

Question: If a married couple has a baby who becomes our patient, what insurance do we bill? The mother covers the child on her insurance. The father does not cover the child with his insurance. Is the father's insurance still primary for the first 31 days of the child's life since the father's birthday is before the mother's?

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Answer: Because the mother is the only parent whose insurance is covering the patient, you would bill the mother's insurance from day one. You'll only follow the "birthday rule" when the child is covered under the insurance plans for both parents -- typically children whose parents are not separated or divorced, or dependent children of parents with joint custody.

Learn the rule: The birthday rule says that for a dependent child of parents who are not legally separated or divorced, the insurance of the parent whose birthday falls earlier in the year is the primary payer. "Birthday" in the birthday rule refers to the month and day in a calendar year, not the year in which the parent was born.