Yeah, actually they DO!! If they have to 'catch' a sample from a dog often they will collect the sample in something like a plastic cup attached to a stick, or a ladle or even a small plastic dish or bedpan -- whatever works for that dog.
A 'caught' sample is cheaper to process -- often they just compare it to a strip that has chemicals on it and the resulting 'colors' it turns indicates if there is infection as long as the urine is concentrated enough;
OR they may send it out for a lab to actually do a "urinalysis" on - and that will break the components of the urine down into it's various parts and it will also test for the presence of crystals and such stuff.
However, if deeper problems or a persistent infection is suspected they may do what is called a "sterile urine draw".
NOT fun for the dog.
A. The first type is with a catheter which is essentially a LONG sterile plastic tube that is inserted from the tip of the urethra (either thru the penis of a male or behind the vulvar area of a female) [let's see what the bad words thing does with THOSE words *sigh*] and that is carefully threaded all the way up inside to the bladder (trust me -- you'd cringe if you saw how long it is -- it's probably 2 feet long for a dog) and then they attach the end of that to the tip of a syringe with no needle and "draw" out the sample.
All the while hoping that the stimulation of the tube doesn't cause the animal to lose control which can mean a pint of urine going all over the place).
B. The other type of sterile urine draw is a needle aspirate. They have to be able to palpate the kidney/bladder area (meaning the dog has to be pretty darned full) and they literally pierce the animal's side with a syringe with a LONG needle on it and directly go right into the bladder (usually the bladder not the kidney I think, but I've only seen it done, not done it myself -- to which Billy says PHEWWWWWWWWWWWW). They literally suck out the urine sample so it avoids the urethrea.
Why? this way if the tip of the penis or the vulva is, itself, infected, you can get a better idea of where the infection comes from .. and it's sometimes seen as a more "sterile" way of doing it IN CASE the inside of the penis and vulvar area are in any way contaminated.
HOWEVER ... double-edged sword here -- because in simply piercing the organ with a needle you can also get BLOOD in the urine sample and one of the things you are testing FOR is the presence of any blood (which indicates different types of problems).
So IF IF IF this extreme type of urinalysis is necessary (and usually it's not) usually a vet will have a definite preference over which way he wants to do it.
this is a definite stressor to the dog -- this is NOT fun in either event, so usually a vet has a pretty definite idea of whether a caught sample will be fine or IF the 'sterile' sample is needed.
Also - since we're doing the whole "scoop" here on urinalysis -- there is one more component they can do.
Like with any aspirate or culture involving a potential serious infection (whether it's yuck from deep inside the ear canal or a surface but bad skin infecton OR a UTI or bladder infection) they can take that 'sterile' culture and grow bacteria from it and then subject it to various antibiotics to see which ones kill the bacteria best ... worst ... or don't kill it iat all. This added step is called a 'culture and sensitivity' test. Usually adds a good $50 or so to the cost of the urinalysis (which might be like $40)
This takes days to come back because not only do they do the typical urinalysis results they have to take time to 'grow' a culture and then see what kills it.
For example -- all the nasty horrible UTIs Billy has had while he's been on the immune supressors while he was treated for the IMHA -- we had to have several "culture and sensitivities" done
But any time you are having a problem with an infection -- it's not responding to treatment or HOW it is treated is going to be a big deal -- a culture and sensitivity test is sometimes an awfully good thing to have. It can save you weeks of treating with the wrong antibiotic when you may need to go to a bigger antibiotic because of some sort of resistance.
I've had cultures and sensitivities done on dogs with ear problems and with urinalysis and even with skin problems.
But for just a plain old "caught" sample -- yep, they use a cup!! (for a boy). For a girl dog you can use a small Glad disposable dish or anything low and cup-shaped.
You can take in your OWN sample if it's easier on you and the dog. Billy has had so many of these done in the past year and a half I can actually say to him when we leave the car "DON'T pee -- the girls have to get a sample!!" and he'll SCURRY to the door and stand there with his eyes crossed waiting for them to take him out.
He's VERY unusual (and it's only because he's had 100's of tests done on him in the past year). But I've had dogs who would lead you a merry chase and would rather burst than let you catch a sample. then I've also had dogs who would simply look at you like "Ummm -- usually that stuff runs into the grass ... what ARE you doing, Mom???"
BUT kidding aside -- if you catch your own sample you GOTTA refrigerate it right away. Take an old cooler and use it for JUST this if you want .. but put a sterile top on that container (the container you use MUST be clean clean clean -- usually I pour boiling water over it to make sure it's sterile before I use it). If it doesn't have a 'top' you can pour the sample in a baggie. But it's GOT to be refrigerated and NOT frozen and then get it right to a vet.
Don't let it sit out at all -- it's got to be seen quick or bacteria will grow that weren't there to begn with. Put the time/date on the bag and get it right straight to the vet.