<prompt> Phenylpyruvic acids in the urine is detected by:Guthries testVMA in urineGerhas testFerric chloride test  <response>: Ferric chloride test is a quantitative test for the detection of phenylketonuria; the addition of ferric chloride to urine give rise to a blue green colour in the presence of phenylketonuria. This colour is due to phenylpyruvate. 