How to read a urinalysis
A urinalysis is not one test. It is three, run on the same sample, and knowing which part a finding came from tells you how much weight it carries.
1. The visual exam
Someone looks at the sample and writes down its colour and clarity. Urine should be clear and straw-coloured. Cloudy urine usually means it is concentrated — you have not drunk enough — but it can also mean cells, crystals, or bacteria are suspended in it. Dark, tea- or cola-coloured urine can mean blood or a liver problem. This part of the test is the crudest and it is almost never conclusive on its own.
2. The dipstick
A plastic strip with chemical pads is dipped into the urine, and each pad changes colour to signal leukocytes, nitrites, blood, protein, glucose, ketones, bilirubin, urobilinogen, pH, and specific gravity. It takes about a minute and it is designed to be over-sensitive on purpose — the job of a screening test is to catch things, and it accepts false alarms as the price.
This is why a positive dipstick is not a diagnosis. A trace of protein can be a fever, a hard run, or a very concentrated sample. Leukocytes can come from vaginal discharge that got into the cup. Blood can be your period. Ketones can be breakfast you skipped. The strip is telling you something is here — not why, and not whether it matters. Roughly the opposite is also true: a clean strip does not clear you, because a dilute sample can wash a real finding below the threshold the pad can detect.
3. The microscopy
If the dipstick flags something, the lab spins the sample and looks at the sediment under a microscope: red and white blood cells, bacteria, crystals, epithelial cells, and casts. Casts are the most informative thing on the whole report, because they form inside the kidney's own tubules — a cast proves the finding came from the kidney rather than the bladder or urethra.
Why a culture is what confirms a UTI
Leukocytes plus nitrites is the textbook dipstick picture of a urinary tract infection, and it is a genuinely useful signal. It is also not proof. A urine culture — growing the sample for a day or two — is what actually confirms an infection, identifies which bacterium is causing it, and shows which antibiotics will work against it. That last part matters more every year, as resistance spreads.
The gap between the two tests is where a lot of women get lost. A negative nitrite does not rule out a UTI: several bacteria that cause infections do not produce nitrite at all, and urine has to sit in the bladder for hours before enough accumulates to register. And bacteria on a report do not automatically mean you need antibiotics — asymptomatic bacteriuria, bacteria present with no symptoms, is common in older women and, outside of pregnancy, guidelines say it should generally be left alone. Treating it does not help and it drives resistance.
So: if you have classic UTI symptoms and a matching dipstick, a clinician may reasonably treat you without waiting. But if your infections keep coming back, if a course of antibiotics did not fix it, if your symptoms persist while your dipstick is clean, or if you are pregnant — ask specifically whether a culture was sent. Recurrent UTIs are more common after menopause, when falling estrogen thins the tissue of the vagina and urethra, and repeatedly treating the wrong thing is a well-worn path.
The finding never to explain away
Blood in urine always needs evaluating. Visible blood, or microscopic blood with no clear cause, is not something to watch and wait on. Painless blood — no burning, no pain, no symptoms — is the classic first sign of bladder or kidney cancer, and because it typically stops on its own after a day or two, it is one of the most commonly dismissed findings in medicine. Women in particular are more likely to have it attributed to a period, a UTI, or menopause and then not followed up, which is part of why bladder cancer in women is diagnosed later and at a more advanced stage than in men.
None of that means blood in your urine is cancer — most of the time it is a UTI, a stone, or your period. It means the finding earns a proper answer rather than an assumption. If a period or an infection is the presumed cause, the standard of care is to recheck the urine afterwards and confirm the blood is actually gone.
What to do with a result you do not understand
Bring the actual printout to your appointment and ask three questions: Which of these findings do you think matter? What is the most likely explanation, and what else could it be? What is the next test if this does not resolve? A urinalysis is a starting point in a conversation — its whole value is in what gets checked next.
Go deeper on the individual findings: leukocytes in urine, blood in urine, protein in urine, and what the colour of your urine does and does not tell you in our urine color chart. If a UTI is the likely answer, start with urinary tract infections. For blood tests rather than urine, use understand your lab results, and browse everything we have on bladder & urinary health.