At any time we interprete paediatric chemical pathology test results we must take into consideration a number of factors, which are related with and restricted to paediatric patients. Such factors include the paediatric patient's age that may change from prematurity to above 18 years, and the paediatric patient's body weight can vary from 500 grams (gm) to more than 60 kilograms (kg). The mass of the body of the paediatric patient can also in some circumstances or conditions be a factor, especially for example, obesity in childhood. A paediatric patient is not a miniature adult patient, but as a paediatric patient gets older and becomes mature his or her metabolic processes and the body biochemistry become more like that of the grown-up. In addition to the paediatric subject's or patient's non-controllable variables or factors are the effects of controllable variables or factors, which include; blood sample collection process, method of sample analyses or measurement techniques, are the basis for the reference interval or range that are often cited with the test result, and the explanation or interpretation, which are often given to the test result by the chemical pathologist or the laboratory physician.
Key words: age-dependent, prematurity, puberty.