A biochemical test is performed for assessing the level of protein or enzyme activity in a sample, according to the National Human Genome Research Institute. It is a type of genetic test that is frequently used for newborn screening.
If a newborn has a metabolic condition like PKU or phenylketonuria, the test can detect it. Due to a genetic defect, an infant with PKU does not have enough of the enzyme that breaks down phenylalanine, a type of amino acid.
Biochemical tests are also used for identifying various types of gram-positive and gram-negative bacteria. Examples of biochemical tests are the catalase test, nitrate broth, motility agar, urease test and oxidase test.