Urinalysis

A urinalysis examines your urine for signs of kidney disease, diabetes, urinary tract infection, and liver problems. It is one test that produces around a dozen separate results, split across three groups: what the sample looks like, what a chemical dipstick detects, and what a microscope finds.

What a urinalysis measures

Urine is what your kidneys filter out of your blood, so its contents reveal both how well the kidneys are working and what is circulating in your body. A complete urinalysis runs in three parts.

Physical. Color and clarity give the first impression, and specific gravity measures how concentrated the sample is, which reflects hydration and the kidneys' ability to concentrate urine.

Chemical. A reagent strip detects pH, protein, glucose, ketones, blood, bilirubin, urobilinogen, nitrites, and leukocyte esterase.

Microscopic. If the physical or chemical findings warrant it, the sample is examined under magnification for red blood cells, white blood cells, epithelial cells, bacteria, crystals, and casts, including hyaline, granular, and red blood cell casts.

What the results mean together

Individual findings matter less than the patterns they form.

Nitrites together with leukocyte esterase and white blood cells point toward a urinary tract infection. Glucose in urine suggests blood sugar has exceeded what the kidneys can reabsorb. Protein raises the question of kidney filtration damage, though the microalbumin test detects that far earlier and more precisely. Blood can come from anywhere along the urinary tract, and red blood cell casts specifically localize it to the kidney itself. Bilirubin and urobilinogen relate to liver and bile function.

Many findings are also benign or transient. Concentrated urine from mild dehydration changes color, specific gravity, and can produce trace protein. Squamous epithelial cells usually mean the sample picked up skin cells during collection rather than anything internal.

Urinalysis FAQ

Do I need to fast for a urinalysis?

No, but the sample quality matters. A first-morning sample is the most concentrated and most informative, and a clean-catch midstream collection reduces contamination from skin cells and bacteria.

My urinalysis showed trace protein. Should I be concerned?

Usually not on its own. Trace protein can appear with dehydration, fever, or recent intense exercise. The microalbumin test is far more sensitive and is the better marker for detecting early kidney changes.

Why did some results come back with no microscopic findings?

The microscopic examination is typically performed only when the physical or chemical results suggest it is needed. A clean dipstick with normal appearance often means no microscopy was required.

Read alongside Microalbumin, Creatinine, and Estimated glomerular filtration rate for a complete picture of kidney health.

Sources

• MedlinePlus Medical Encyclopedia, Urinalysis.

• Cleveland Clinic, Urinalysis.