What is the Guthrie test and why is it done?

The Guthrie, or heel prick test is a screening test carried out on your newborn baby in the days after birth (typically day 6 or 7). The Guthrie is offered to all infants in the U.K. with the aim of screening for up to 5 disorders (depending on your health authority). Blood is taken from your baby’s heel. The sample is analysed for the following conditions:

• Phenylketonuria all UK areas
• Congenital Hypothyroidism all UK areas
• Cystic Fibrosis most UK areas
• MCAD Deficiency fewer UK areas
• Sickle Cell Disease fewer UK areas

Phenylketonuria is condition that affects the individual’s ability to metabolise a particular type of amino acid – phenylalanine. A build up of this can lead to severe mental handicap. Simply avoiding exposure to phenylalaine can minimise the effects of the condition.

Congenital Hypothyriodism is characterised by a lack of the growth hormone thyroxine. Without this hormone, normal growth cannot occur. This condition is treated with supplements of the growth hormone.

Cystic Fibrosis is an inherited condition that affects the lungs and digestive system.

MCAD (Medium Chain acyl-CoA Dehydrogenase) Deficiency is a condition in which fat metabolism is impaired. Modification of the diet can reduce symptoms.

Sickle Cell Disease affects the shape of red blood cells and reduces their ability to carry oxygen around the body.

These conditions can all be treated to a greater or lesser extent, which is why it is so worthwhile screening for them. If you are not sure which disorders are screened for in your area or have a particular concern about any part of the test, ask your midwife.