Although these are by far the commonest sample sent to the laboratory, they
seem to attract the least attention to detail. About one quarter of requests
are either obviously contaminated (judging from the presence of vulvo-vaginal
squamous epithelial cells in the urine) or arrive in the laboratory the day
after the specimen was passed by the patient. Up to half the requests from
wards have no relevant clinical information to indicate why the sample has been
sent. And 15 to 20% of them have significant antibacterial activity present
without any pointers to this possibility being noted on the request form. The
great majority of 'sterile pyurias' can be attributed either to pseudo-pyuria
of vulvo-vaginal origin or to antibiotic therapy.
In the female, introital cleansing is the
most important determinant of a 'clean' specimen. Collection can usually be
deferred until immediately after the patient has showered or bathed. Among
bed-bound patients the risk of contamination is considerably greater so all the
more attention should be paid to the simple expediency of perineal and
introital cleansing; the mid-stream aspect then becomes much less important.
Only soap and water, never disinfectants, should be used for cleansing.
'Dip-stick' tests for glucose, protein, blood, etc. are not routinely performed
on urine samples submitted for microbiological tests because such screening has
usually already been done on the ward, or in the clinic or surgery. Such tests
will be undertaken if the request form clearly indicates that this is required.
Culture and sensitivity
|Inform lab before sending||No (unless urgent)|
|Specimen type||Mid-stream urine (MSU)|
Ileal conduit urine
|Ideal time to take speciemn||Before antibiotic therapy|
|Specimen container||Sterile leak proof container (see above)|
|Labelling requirements||click here|
|How to take specimen||See above|
|Volume||5 - 10ml|
|Transport to the laboratory||If transport is delayed then refigerate sample. Delays of over 48 hours are undesirable|
|Turnround||Negative urines <24 hours,|
Positive urines 24 - 48 hours
|Additional information||Any samples suspected of containing organisms belonging to hazard group 3 (e.g. TB) should be clearly marked as such on the request form.|
Biochemical dipstick tests are not performed in the Microbiology laboratory as such tests are usually performed as near patient testing.
|Specimen retention||Please ensure that any requests for additional investigations on the specimen are made within 3 days from the date of the original request|