Urinalysis with Reflex to Culture

Color and appearance

The lab records the color and clarity of your urine. Color mostly reflects how concentrated it is, and it can also change with foods, vitamins, and medicines. Cloudiness can come from cells, crystals, or bacteria, so it is read with the other urinalysis results.

Why it’s measured: A first look at how concentrated and how clear your urine sample is.

Specific gravity

Specific gravity measures how concentrated your urine is compared with water. It reflects how much you have been drinking and how well your kidneys concentrate urine. A provider reads it with your other results, since concentrated urine can make other values look higher.

Why it’s measured: Shows how concentrated your urine is, which affects how other results are read.

pH

Urine pH shows how acidic or alkaline your urine is. It varies with diet, some medicines, and how your body is balancing acids. On its own it says little, but it can add context for kidney stones or a urinary infection when read with your other results.

Why it’s measured: Shows how acidic or alkaline your urine is, which adds context to other results.

Protein

Healthy kidneys keep most protein in the blood, so urine usually has little or none. Protein in urine can appear for a short time with exercise, fever, or dehydration, and can also relate to kidney stress. A positive result is often rechecked before it is interpreted.

Why it’s measured: Protein in urine can be a kidney signal, and a positive result is often rechecked.

Glucose

Glucose usually stays in the blood, and urine has little or none. Sugar can spill into urine when blood sugar runs high, and some medicines for diabetes, heart, or kidney conditions cause it on purpose. A positive result is read with a blood glucose or A1c result and your medicines.

Why it’s measured: Sugar in urine is read together with a blood glucose or A1c result.

Ketones

Ketones are made when your body burns fat for energy instead of sugar. They can appear in urine with fasting, low-carbohydrate eating, intense exercise, or vomiting, and with high blood sugar in diabetes. A provider reads the result with your circumstances.

Why it’s measured: Shows whether your body has been burning fat for energy instead of sugar.

Bilirubin

Bilirubin is a yellow substance made when old red blood cells break down, processed by the liver. It does not usually appear in urine. Finding it can relate to the liver or bile ducts, so a positive result is read with blood liver tests.

Why it’s measured: Bilirubin in urine can relate to the liver and is read with blood liver tests.

Blood (occult)

This checks for red blood cells or hemoglobin in urine that may not be visible. It can be positive with menstrual blood in the sample, hard exercise, infection, or kidney stones, and for other reasons that a provider may want to look into. The microscopic exam adds detail.

Why it’s measured: Checks for blood in urine that you may not be able to see with your eyes.

Nitrite

Some bacteria that cause urinary infections turn nitrate in urine into nitrite. A positive nitrite result can point to a bacterial urinary infection. A negative result does not exclude one, since not all bacteria make nitrite and urine needs time in the bladder.

Why it’s measured: A positive result can point to a bacterial urinary infection, read with other results.

Leukocyte esterase

Leukocyte esterase is an enzyme released by white blood cells. Finding it in urine suggests white cells are present, which can happen with a urinary infection or inflammation. It is read with the nitrite result and the microscopic exam.

Why it’s measured: Suggests white blood cells are in your urine, read with nitrite and the microscopic exam.

Microscopic exam: white cells, red cells, epithelial cells

Under the microscope, the lab counts white blood cells, red blood cells, and cells shed from the lining of the urinary tract. Higher counts can relate to infection, inflammation, or other changes. Skin cells in the sample can also show that it picked up contamination.

Why it’s measured: Counts white cells, red cells, and lining cells in your urine under the microscope.

Microscopic exam: casts and crystals

Casts are tiny tube-shaped particles formed in the kidneys, and crystals form from minerals in urine. Some are common and harmless; others can relate to kidney conditions or a tendency to form stones. The lab reports what it sees for a provider to interpret.

Why it’s measured: Looks for particles formed in the kidneys and mineral crystals.

Microscopic exam: bacteria and yeast

The lab reports any bacteria or yeast seen under the microscope. They can point to an infection, but they can also come from skin contamination during collection, which is why a clean-catch, midstream sample matters. A urine culture can identify the organism.

Why it’s measured: Shows whether bacteria or yeast are visible, which a culture can then identify.

Urine culture (if urinalysis meets set criteria)

If your urinalysis shows signs that can go with infection, such as white blood cells, nitrite, or bacteria, the lab grows a culture from your sample. A culture shows whether bacteria are present and which ones, so a provider can decide on next steps.

Why it’s measured: Added by the lab when the urinalysis suggests a possible infection.

• Your number next to the lab’s reference range
• Explained in plain language
• A licensed clinician reviews your order and, if appropriate, orders the test.
• A lab report you can download and share

Treatment decisions are made with a healthcare provider, so share your results with one, and get care promptly if symptoms get worse.