blood phenylalanine concentration - normal at birth but rises thereafter (more rapidly in males). Blood screening for phenylalanine identifies most cases at the age of 1 week; urinary analysis at this stage is less accurate. Concentrations of many other amino acids in the blood are generally significantly reduced
phenylalanine challenge - this is contraindicated in patients with known phenylketonuria - if this is undertaken then plasma tyrosine does not rise
Add information to this page that would be handy to have on hand during a consultation, such as a web address or phone number. This information will always be displayed when you visit this page