Fölling rehearsal
The Fölling sample is used to detect an increased excretion of phenylpyruvic acid , a breakdown product of the amino acid phenylalanine . Phenylpyruvic acid is excreted in the urine in high concentrations in the congenital metabolic disorder phenylketonuria .
If iron (III) chloride is added to freshly acidified urine , a characteristic green color occurs in the presence of phenylpyruvic acid. The change in color of the urine or the sample solution results from the reduction of Fe (III) to greenish Fe (II) .
The Fölling test can also be carried out by dripping the ferric chloride solution onto a diaper moistened with urine ("diaper test"). The test was developed by the Norwegian doctor Ivar Asbjørn Følling in the 1950s, but is no longer used in today's newborn screening.
Individual evidence
- ↑ Selective screening for inborn errors of metabolism , Böhlers et al., SPS Verlagsgesellschaft, Heilbronn, 2002.