Child >1 year 24 hour urine in plain bottle with min. 30mL aliquot
Child <1 year min. 20mL random urine (pool several spot urines to get sufficient)
A 24 hour sample IS PREFERRED and will give the most accurate interpretation of the profile as the exact concentrations can be calculated. However if the collection is difficult, an assessment of the pattern can be made, but the reliability is not as good.