Vomiting, sleepiness, seizures, low blood sugar, acidosis, or high ammonia can sometimes look like infection, epilepsy, stomach flu, or even psychiatric illness. But in some children and adults, these symptoms may point to an inborn error of metabolism. In this video, we explain how doctors use first-line biochemical tests—plasma amino acids, acylcarnitine profiles, urine organic acids, urine amino acids, and urine acylcarnitines—to look for clues of small-molecule metabolic disorders. You will learn what these tests can suggest, including PKU, maple syrup urine disease, organic acidemias, fatty acid oxidation disorders, and urea cycle disorders. We also explain why a normal report does not always rule out an IEM, why timing matters during an acute crisis, and why blood and urine results must be interpreted together. This video is for educational purposes only and does not replace medical diagnosis or treatment by a qualified clinician.
