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Newborn Screening Ontario
Health Care Providers

Sample Collection FAQ

Here are some commonly asked questions about the collection of newborn screening samples.

  • A baby who is several months old has not had a newborn screen. Can I take a newborn screen for this baby?

    Yes. However, the newborn screen is the most accurate in the newborn period and most of the conditions screened for become apparent in early infancy.

  • A baby is going to be transferred to another hospital. Should we perform a newborn screen ?

    If an infant is transferred to another hospital, ensure there is communication between hospitals regarding the responsibility for performing the newborn screen. If the transfer will occur after 24 hours of age, the sending hospital should collect the blood spot card before the transfer. Always ensure collection is documented in the newborn’s medical record.


  • A baby is premature. When should I take the newborn screen?

    For babies who are premature (gestational age at birth is less than 33 weeks) or very low birth weight (<1500g) it is recommended that a first newborn screening sample be collected between 24 and 48 hours of age and a second sample collected at 3 weeks of age. If a newborn has a <24 hour sample taken pre-transfusion and a post-transfusion sample taken after 24 hours, a 3 week repeat sample is still recommended to complete screening for congenital hypothyroidism.  Please see the Newborn Screening Manual for further details.


  • Whose responsibility is it to obtain the newborn screening sample?

    It is the responsibility of the hospital/midwifery practice where the baby is born to obtain the newborn screen. All sample repeat requests go to the original submitter.

  • A baby is going to be discharged prior to 24 hrs. Should I take a newborn screen?

    Yes. A newborn screening sample should be taken on every baby prior to discharge. If this happens before 24 hours, parents should be informed that a repeat newborn screen after 24 hours, and within 5 days of the initial sample, will have to be done and directions should be provided on how to complete the newborn screen. The healthcare provider who submitted the original sample is responsible for ensuring a repeat sample is collected.

    Tip: some submitters provide parents/guardians with a follow-up appointment upon discharge to obtain a repeat sample if the initial sample was taken less than 24 hours of age.


  • A baby is going to have a packed red blood cell transfusion (PRBC). Should I take the newborn screen prior to the transfusion?

    If possible, it is best to take the newborn screen prior to a packed red blood cell (PRBC) transfusion, regardless of the baby’s age. PRBC transfusions are known to affect the results of hemoglobin and galactosemia screens. If the baby is less than 24 hours old when the pre-transfusion sample is collected, a second sample is required, ideally taken between 24-48 hours. An additional repeat sample may be required in 4-6 months, which will be determined after the sample has been received at NSO. The doctor report will indicate whether or not a repeat sample is needed. 

    If the newborn screen was not taken before the PRBC transfusion, collect the sample 24-48 hours after the transfusion. NSO will request a repeat sample be taken 4-6 months after the last transfusion to complete screening.


  • A baby has received FFP (fresh frozen plasma) and platelets. Does this constitute a blood transfusion?

    This is not considered a blood transfusion for newborn screening purposes. Provided that a baby has not received red blood cells, you may indicate “no” for transfusion status.

  • The baby’s parents are refusing the newborn screen. What should I do?

    If you have thoroughly explained newborn screening to the parents and they choose to decline the test, it is extremely important to document it in the baby’s records. You may have the family complete the Decline/Defer Form on the back of the newborn screening card.

  • The baby is being adopted. Whose demographic information should be listed in the “mother/guardian” section?

    Please indicate that the baby is being adopted and include the adoptive parent’s information (as s/he will be caring for the infant and would be the person to contact in the event the infant screened positive). The new version of the newborn screening card has a check box for “Adoption".

  • The baby is in the care of Children’s Aid Society (CAS). What information should I put in the “mother/guardian” section?

    Please clearly indicate that the baby is in CAS care and provide the baby’s caseworker’s name and contact phone number (the caseworker would be the person to contact in the event the infant screened positive). The new version of the newborn screening card has a check box for “CAS care.”

  • How should I discuss newborn screening with the parents/guardians?

    Information about newborn screening is best provided to the parents/guardians prenatally, and reinforced after the baby’s birth.  Discuss the importance of newborn screening and what the dried blood spot test entails, to ensure they are informed and have the opportunity to ask questions prior to the screen being completed. Each newborn screening card has an information letter that should be provided to the parents/guardians before the heel prick is performed. NSO pamphlets can also be provided; these are available in multiple languages through the MOHLTC free of charge.

  • Our newborn screening cards have expired. How do we get new ones?

    The expiration date is indicated in year-month format on the upper right corner of the newborn screening card; this should be checked before collecting a newborn screening sample. If the card has expired, use another card for blood specimen collection. If all of your cards are expired, order new cards as soon as possible. In the meantime, collect newborn screening samples on the expired cards. NSO tests all samples received on expired cards; however, the sample is considered unsatisfactory and a repeat sample will be required.

    Steps for ordering new cards can be found on our website: Supplies & Resources | CHEO NSO (

  • A baby is receiving TPN. Do I need to hold this prior to collecting the newborn screen?

    Yes. If the baby is receiving any solution containing amino acids, the solution should be held for 3 hours prior to collecting the newborn screening sample when possible. The amino acids in TPN can influence the amounts being measured in the newborn screen, and thus impact the baby’s screening results.

  • Can NSO provide newborn screening results to parents/guardians?

    As a laboratory, NSO is not able to provide results directly to parents/guardians. Newborn screening results are sent to the hospital or midwifery practice that ordered the screen, by fax and/or electronically through the Ontario Laboratories Information System (OLIS). Parents/guardians should contact the birth hospital or midwifery practice group to obtain their results, if desired.

    When a baby’s parent, guardian, or healthcare provider requests results through the request form on the NSO website, results will be sent to the health care provider listed on the form. Please note that we are not able to send results to health care providers outside of Canada.