How do I prepare for the test?
- For a regular urinalysis, you are asked to urinate briefly
into a plastic cup. When urine is collected for a urine culture,
you must provide a "clean catch" sample - one that is not contaminated
by skin cells and skin bacteria. This is so the doctor can obtain
a sample of urine from inside your bladder, where normally there
should be no bacteria. In contrast, there are many bacteria on
the skin of a penis or in a vagina. The trick (harder for a woman
than a man) is to pee directly into a sterile container without
having the stream of urine first touch your skin or the nonsterile
tissues of the vagina.
To collect a clean catch sample, you are given a sterile plastic
container and asked to wipe off the area around your urethra
(where urine exits) with an antiseptic cloth. For women, it's
also helpful to hold the two labia (outer walls) of the vagina
apart with one hand when you urinate, so that the stream of urine
passes directly into the sterile container. Since the first flow
of urine is most likely to be contaminated by bacteria from around
the opening of the urethra, first urinate for a moment into the
toilet and then use the cup to collect the "middle" portion of
your urine stream.