What happens if a newborn screening test comes back negative?

Within 2 to 3 weeks after newborn screening tests are performed, results are sent to the baby's doctor's office or clinic. A negative result means that all of the tests are in the normal range, and they do not indicate any increased risk. Other words for a negative test result are "passing," "in-range," or "normal."
In most cases, families are not notified of negative results. Parents can contact their baby's healthcare provider if they wish to confirm that the results were negative. Usually no follow-up testing is necessary.
Rarely, the results of a newborn screening test can be a false negative. "False negative" means that a disease was missed by the screen; the test results came back negative, but the child actually has the disease. Possible reasons for a false negative result include laboratory errors, such as mixing up samples, and doing the test too early. Because false negatives are possible, further testing should be done if a baby has a family history of a particular disease or shows signs and symptoms, regardless of the newborn screening result.