Newborn Screening Information for Providers:
Blood Spot Screening Results
A “negative” result means that the screen was normal for that particular disorder and no additional follow-up is required.
Note: Because newborn screening is not diagnostic testing, false negative results may occur. Should a child display symptoms of a disorder for which the screen was negative, evaluate the child immediately. Newborn screening should not replace diagnostic testing in any circumstances. If the child is found to be affected, please contact the Newborn Screening Program regarding the false negative result.
A “borderline” result means test results were between normal and abnormal. In these circumstances, Newborn Screening Program staff will call and request a subsequent specimen or follow-up labs. If the subsequent specimen remains borderline or becomes a positive result, Newborn Screening Program staff will contact the infant’s care provider and recommend diagnostic evaluation.
“Abnormal” results appear on the newborn screening report for some of the disorders on the newborn screening panel. If an infant receives an abnormal result requiring clinical follow-up, Newborn Screening Program staff will contact the infant’s care provider to discuss the abnormal result and fax the information needed to notify the parents and properly follow-up on the result. Newborn Screening Program staff can also connect the provider to medical specialists experienced in diagnosing and treating children with the particular disorder.
All “positive” results require follow-up diagnostic testing. In the event of a positive result, Newborn Screening Program staff will contact the infant’s care provider to discuss the result and fax the information needed to notify the parents and properly follow-up on the result. Newborn Screening Program staff can also connect the provider to medical specialists experienced in diagnosing and treating children with the particular disorder.
Note: Newborn screening is not diagnostic testing. Children may receive an abnormal or positive result but later be found to be unaffected by the disorder. Although false positives do occur, it is crucial that all abnormal or positive results receive attention and appropriate follow-up in a timely manner. Like all screening tests, newborn screening inherently generates false positive results in order to avoid missing affected infants.
An “A>F” result means that there was more adult (“A”) hemoglobin than fetal (“F”) hemoglobin identified in the infant’s blood spots. The reason for this result affects how the result should be interpreted by the provider.
One possible reason for an A>F result is a transfusion prior to blood spot collection. If an infant receives donor blood prior to blood spot collection, some screening tests may reflect the status of the adult donor rather than the infant. Collecting a specimen too soon after a transfusion can affect the result interpretation for the following conditions: biotinidase deficiency, cystic fibrosis, galactosemia, hemoglobinopathies, and severe combined immune deficiency. If the infant demonstrates symptoms of any of these conditions, evaluation and consultation with the appropriate specialists should occur.
Another possible reason for an A>F result is that the infant’s fetal hemoglobin switched to adult hemoglobin prior to blood spot collection. If a provider confirms that the infant was not transfused, the result should be interpreted as negative/normal for all conditions listed as A>F and no further testing is required.
A “trait” result indicates that the infant is likely a carrier of a particular hemoglobinopathy. If additional testing is necessary, it will be indicated on the newborn screening report.
An “unsatisfactory” result means that screening results cannot be accurately interpreted because of a problem with blood spot collection, inaccurate information on the newborn screening card, or a problem with the infant’s age.
Most unsatisfactory results occur because of problems with blood spot collection, such as collecting blood on an expired card, blood spots were more than 14 days old by the time the laboratory received them, or poor quality blood spots were collected. If an infant’s blood spots are deemed unsatisfactory, Newborn Screening Program staff will call the original submitter and request the collection of another specimen. The collection of a subsequent specimen is required unless the parent refuses in writing.
Sometimes results are classified as unsatisfactory because inaccurate information is provided on the newborn screening card. The most common cause of this error is a mistake with a date on the card. If inaccurate information provided on the newborn screening card leads staff to question the identity of the infant, program staff will request a repeat specimen.
Another reason results may be unsatisfactory may be a problem with the infant’s age. Some of the newborn screening tests have age cut-offs, meaning results cannot be accurately interpreted if a child does not meet the minimum age requirement or exceeds the maximum age for that particular disorder. Depending on the issue, additional screening or testing may be recommended on the newborn screening report.
A “pending” result means that screening is incomplete for one or more of the disorders on the newborn screening panel, but a preliminary report has been released to the infant’s provider to facilitate follow-up for any abnormal or positive results. A final report will be sent to the submitting facility/provider once all tests have been completed. If a final report indicates that a result is still pending, please contact the Newborn Screening Program.