Guthrie test

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Key messages from UK National Screening Committee:

• The blood spot is taken between day 5 & 8. Birth is counted as day 0
• Screening is recommended but parents may decline one or all of the tests
• Babies found to be affected are referred to a specialist paediatrician direct from the laboratory
• Parents usually receive all results by six weeks and it should be recorded in the personal child health record
• http://newbornbloodspot.screening.nhs.uk/

The National Screening Committee recommends that newborn blood spot screening include:

• Congenital Hypothyroidism (CHT)
• Sickle Cell disorders
• Cystic Fibrosis (CF)
• six inherited metabolic diseases (IMDs)
  • phenylketonuria (PKU)
  • medium-chain acyl-CoA dehydrogenase deficiency (MCADD)
  • maple syrup urine disease (MSUD)
  • isovaleric acidaemia (IVA)
  • glutaric aciduria type 1 (GA1) and
  • homocystinuria (pyridoxine unresponsive) (HCU)

Blood spot screening is offered to all babies up to one year of age, with the exception of CF where the test is valid up to 8 weeks of age only CF screening may detect some but not all carriers, SCD screening also detects carriers. Local pathways exist for communicating carrier status.

Babies born preterm require an admission blood spot sample in addition to the routine day 5 sample and a repeat test for CHT.

A "pre transfusion" bloodspot sample should be taken for SCD before babies are transfused. The card should be marked as "pre transfusion" and sent to the newborn lab with the routine day 5 sample

Babies who have a blood transfusion before testing require a repeat test for PKU, CHT, CF and MCADD 72 hours after the last transfusion.

Babies who screen positive are referred to a specialist team directly from the laboratory and GPs are informed of this.

Timeliness is important and treatment for PKU and CHT should start by 17 days of age or earlier. Screen positive sickle cell results should be communicated to parents by 4 weeks of age and these babies should be registered with a designated clinic by eight weeks of age.

Screen positives for MCADD are seen within 24 hours to enable parents to be alerted to immediate action they should take should the baby become unwell.

Results are sent from the laboratory to the child health records departments, for communicating to parents.

GPs can help enormously by ensuring that newborn screening results are recorded in the personal child health record when the baby attends for 6-8 weeks infant physical.

For healthcare professional resources and parent information leaflets go tohttp://newbornbloodspot.screening.nhs.uk/professionals

The test was previously known as Guthrie or the heel prick test.