StacksVerified U.S. regulatory reference

21 CFR §862.1555

Verified against eCFR.gov as of June 20, 2026View official text on eCFR.gov ↗
  1. (a)Identification. A phenylalanine test system is a device intended to measure free phenylalanine (an amino acid) in serum, plasma, and urine. Measurements of phenylalanine are used in the diagnosis and treatment of congenital phenylketonuria which, if untreated, may cause mental retardation.
  2. (b)Classification. Class II.