Cystocentesis is done for a few reasons but we'll stick with just urinalysis'. If a UTI is suspected, a urinalysis and culture and sensitivity should be done. The C/S is best done from a sterile sample and the culture should be taken from a fresh, non-refrigerated sample. SO the only way to do this is by cysto.
Free catch samples do contain a lot more bacteria, not only from the non-sterile container/pee pad/floor/whatever it is collected from, but from the lower urinary tract system. the urine that goes thru the urethra and out of the penis/vagina is not an accurate representation of what is in the bladder.
When a cysto is done and a culture is taken any bacteria found on the petri dish is significant. everything used to take the sample was sterile therefore there was no contamination (unless there is a human error which is possible). sterile syringe with sterile needle -> sterile prep site ->sterile sample -> sterile culture swab -> sterile petri dish.
When a free catch is done there will be bacteria in it, and there could be multiple kinds of bacteria. its hard to say what bacteria came from within the bladder and how much of it was in the bladder if any.
Also, urine samples that are taken at home by free-catch and refrigerated can change by the time they get to the vet. refrigeration can cause glucose levels to drop, crystals to dissolve, clarity changes, and cell disintegration.
__________________ Kellie  and  Morgan |