The Ferric Chloride test is a qualitative urine test primarily used to detect the presence of phenylketones, indicative of metabolic disorders like Phenylketonuria (PKU). It reacts with phenols in the urine, producing a color change. Historically used in newborn screening, it has largely been replaced by more advanced diagnostic tests.

Risk Assessment:

1. Chemical Handling Risks:
   • Ferric chloride is corrosive and may cause skin and eye irritation.
   • Proper lab safety protocols (e.g., gloves, goggles) should be followed.
2. Patient Risks:
   • Minimal risks; only involves a routine urine collection.

Normal Range:

• Normal: No significant color change (urine remains yellow).
• Abnormal: A color change (often green, blue, or purple) suggests the presence of phenylketones or other phenolic compounds.

Interpretation of Results:

• Positive Result:

  • Indicates the presence of phenylketones, which may suggest metabolic disorders like PKU, tyrosinemia, or alkaptonuria.
  • Further diagnostic testing is required to confirm the condition.

• False Positives:

  • Occur due to medications, dietary compounds, or improper handling.

• False Negatives:

  • Can happen if the phenylketone concentration is too low or the urine is diluted.

Sample Type:

• Specimen: Random urine sample.
• Volume Required: 10–20 mL.
• Collection Method: Clean-catch midstream sample in a sterile container.