Guthrie test

Guthrie test is a medical screening method used to check for phenylketonuria (PKU) in newborns. Named after its developer, Robert Guthrie, the test has been widely used since the 1960s.

Overview

The Guthrie test is a simple, cost-effective method for detecting PKU, a genetic disorder that can cause intellectual disability if not treated early. The test involves taking a small blood sample from the newborn's heel, which is then placed on a special filter paper and sent to a laboratory for analysis.

Procedure

The Guthrie test is typically performed 48 to 72 hours after birth. The healthcare provider pricks the baby's heel and collects a few drops of blood on a special filter paper. The paper is then allowed to dry and sent to a laboratory for analysis. The lab uses a bacterial inhibition assay to detect high levels of phenylalanine in the blood, which is indicative of PKU.

Importance

Early detection of PKU through the Guthrie test allows for immediate treatment, which can prevent the development of severe intellectual disability. Treatment usually involves a special diet low in phenylalanine, which must be followed for life.

Limitations

While the Guthrie test is effective in detecting PKU, it does have some limitations. For instance, it can only detect high levels of phenylalanine, and not other metabolic disorders. Additionally, the test must be performed after the baby has ingested protein, otherwise, a false negative result may occur.

See Also

• Newborn screening
• Phenylketonuria
• Robert Guthrie

References

Guthrie test Resources
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