chemistry, normal values, the amounts of various substances in the normal human body, determined by testing a large sample of people presumed to be healthy. Normal values are expressed in ranges of numbers, and ranges vary for different age groups and from laboratory to laboratory. For example, a normal concentration of a substance in the blood might be expressed as 5 to 20 mg/dL. Although variations from normal values may be highly significant tools in the diagnoses of certain diseases, in all cases an abnormal result must be cautiously interpreted.
