In general, only small amounts (0.5–1.0 ml) of urine are required,
although the exact volume depends on the method. Some urine should
also be kept in reserve for replicate testing or for external quality control.
Samples are collected in small cups and transferred to tubes, which
should be tightly sealed with screw tops. They do not require refrigeration,
addition of preservative, or immediate determination in most methods.
They can be kept in the laboratory for months or more, preferably
in a refrigerator to avoid unpleasant odour.