The term PKU test refers to a medical diagnostic examination that checks for phenylketonuria, a rare metabolic disorder involving the inability to break down an amino acid called phenylalanine. While there are no direct synonyms for PKU test, the test itself is often referred to as a newborn screening or metabolic screening. In some cases, it may also be called a Guthrie test, named after the creator of the original method used to screen for PKU. Other scientific terms associated with the disorder include hyperphenylalaninemia and phenylalanine hydroxylase deficiency, which are often used interchangeably with phenylketonuria. Overall, the PKU test is a crucial step in identifying and providing early treatment for those with this rare but serious condition.