The urine of individuals with Phenylketonuria (PKU) characteristically turns a dark-green color when tested with ferric chloride.
Understanding Urine Color in Phenylketonuria (PKU)
Phenylketonuria (PKU) is an inherited metabolic disorder that affects how the body processes phenylalanine, an amino acid. If left untreated, the buildup of phenylalanine can lead to various health issues. While the natural color of urine can vary based on hydration and diet, specific diagnostic tests have historically been crucial in identifying PKU by revealing distinct chemical reactions.
The Ferric Chloride Test and PKU Urine Color
A notable historical diagnostic method involves adding ferric chloride to a urine sample. Generally, when ketones are present in urine, this test typically results in a red-brown color. However, in the context of PKU, the presence of specific metabolic byproducts leads to a distinct reaction. When ferric chloride is added to the urine of someone with PKU, the sample uniquely yields a dark-green color.
This specific color change served as an important indicator in the early diagnosis of PKU, differentiating it from other conditions that might also lead to ketone presence in urine.
Key Aspects of the PKU Urine Test
Here's a summary of the characteristic observation in PKU urine testing:
- Test Reagent: Ferric Chloride
- Characteristic Reaction in PKU Urine: Dark-green color
- Distinction: This dark-green reaction is notably different from the red-brown color typically observed when ferric chloride is added to urine containing general ketones.
This unique dark-green reaction provided a historical method for detecting the metabolic abnormalities associated with Phenylketonuria.
