The Guthrie test - Pennine GP Training

Report
‘GUTHRIE’ TEST
UK NEWBORN BLOOD SPOT
SCREENING
By Zoe Skinner
GP ST3 2012
INTRODUCTION
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A blood test to screen for potentially treatable
genetic conditions
Introduced 1963 by Robert Guthrie in Scotland,
nationally 1969.
Filter paper onto which 4 spots require drops of
newborn babies’ blood are collected
Day 5-8 collection. Heel prick by Midwife/Health
Visitor and sometimes doctor (Paediatrics)
INTRODUCTION CONTINUED
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Prepaid envelope, sent on day of collection
Sent to specialist pathology labs - for consistency &
accuracy.
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Not compulsory but recommended
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Screening is not 100% accurate
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Result should be known by 6-8weeks (if clear or
carrier)
**CAN PREVENT SERIOUS
DISABILITY & EVEN DEATH**
PARENTS WHO DECLINE SCREENING
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Record reason for each condition declined or the
whole thing
Enter details on card and mark card as ‘decline’
and send to screening laboratory
GP or Health Visitor should be informed of
parent(s)’ decision
They should be provided with information or
contact should the change their minds
SPECIAL CIRCUMSTANCES
If no recorded evidence of screen, older babies up
to 12months who become the responsibility of the
provider organisation should be offered screening
(UK Newborn Screening Centre)
 Neonatal units & preterm babies
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If admitted to neonatal unit &<5days old or if having
a transfusion-need to complete a single spot ‘pretransfusion card’ as well as the other 4 spots at day
5
If transfused whilst intrauterine or in the newborn
period before day 5 blood spot , repeat sample needed
72hours after transfusion.
If less than 32 weeks-need card at 5 days and second
sample (two spots) to be taken at 28days or before
discharge, marked ‘CHT preterm’
DISORDERS SCREENED
CONGENITAL HYPOTHYROIDISM
 CYSTIC FIBROSIS
 PHENYLKETONURIA (PKU)
 SICKLE CELL ANAEMIA -2005
 MEDIUM CHAIN ACYL Co-A
DEHYDROGENASE DEFICIENCY (MCADD) –
2009
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More rare conditions have been considered and offered in some
countries e.g. Congenital adrenal hyperplasia, Galactosaemia, Bilary
Atresia, Glutaric aciduria type 1, Biotinidase deficiency. Some of
which
the incidence it too low to justify screening although may be
beneficial if
detected. Or the outcome is still poor despite preventing mortality
Taken from Newbornbloodspot.screening.nhs.uk
PKU
About 1 in 10,000 babies in the UK
 Unable to metabolise phenylalanine in food
 Untreated serious mental disability
 Special diet to lead normal life
 Early diagnosis & treatment reduces risk of
neurological handicap from 80-90% to 6-8%
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If thought to have it, parents contacted before 3
weeks and given appointment to see specialist
CONGENITAL HYPOTHYROIDISM (CHT)
1 in 4,000 babies in the UK
 Affects growth, and can develop serious,
permanent and physical and mental disability
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Treatment: Thyroxine replacement
Parents contacted before 3 weeks and referred to
specialist
SICKLE CELL ANAEMIA (SCD)
About 1 in 9,000 babies born in UK
 Inherited disorder affecting red blood cells
 Sickle cell shape can become stuck in small blood
vessels and cause pain, damage, serious infection
and death
 Screening early treatment, including
immunisations & antibiotics. Parent education.
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The screen identifies babies who are genetic
carriers of sickle cell or other unusual red blood
cell disorders.
 Parents contacted before 6 weeks old
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CYSTIC FIBROSIS (CF)
About 1 in 2,500 babies born in UK
 Inherited
 Affects digestion and lungs
 May not gain weight & frequent chest infections
 Treated early with high energy diet, medicines
and physiotherapy
 They still may become very ill but early
treatment is thought to help them live longer &
healthier lives.
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The screen can also pick up carriers, look for
most common gene alterations.
 Parents contacted before 4 weeks old
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MCADD
About 1 in 10,000 babies born in the UK
 Inherited
 Problems breaking down fats to make energy in
the body
 Special diet & ensuring eat regularly
 Can become suddenly and seriously ill
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Parents contacted before 3 weeks and referred to
specialist
THALASSAEMIAS
Rarely other conditions such as beta
thalassaemia major can be identified.
 Babies don’t produce enough red blood cells and
need treatment for severe anaemia.
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WHAT HAPPENS TO THE BLOOD SPOTS??
Stored for at least 5 years
 May be used:
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To check the result or for other tests recommended by
the doctor
 To improve screening programme
 For research & monitoring by Public Health in the
UK. They will not identify baby and will not contact
families.
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‘No research contact’ should be recorded clearly on
the card if families wish not to be involved in
research.
CONCLUSION
One of the largest screening programmes in the
UK
 Over 700,000 newborns are screened each year
 Successful and more than 99% of the babies each
year are screen
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REFERENCE
www.rcpath.org
 Newbornbloodspot.screening.nhs.uk
 www.patient.co.uk/doctor/NewbornScreening.htm
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