Urine test (urinalysis): what it shows and how to give a sample

1. Introduction

A urine test, also called urinalysis, is a physical, chemical and microscopic check of a sample of your urine ^[1]. Urine is made by the kidneys, which filter waste from the blood ^[4]. Urinalysis is used for routine screening for early signs of disease and to look at problems such as diabetes, kidney disease and urinary tract infection ^[1]. This article explains what the test checks, how to give a good sample and how to think about results. Your doctor decides what your results mean for you.

2. Why a urine test is done

MedlinePlus lists several common reasons ^[1]:

• A routine check or general screening.
• Signs of diabetes or kidney disease, or to monitor them.
• Checking for blood in the urine.
• Diagnosing a urinary tract infection, an infection of the bladder or other parts of the urinary system.

Kidney disease often causes no symptoms in its early stages, so testing is the only reliable way to detect it ^{[4, 5]}. MedlinePlus recommends screening for people with diabetes, high blood pressure, heart disease or a family history of kidney failure ^[4].

3. What the laboratory looks at

The laboratory usually examines the sample in three ways ^[1]:

• Visual check: the colour and clearness of the urine.
• Microscope check: cells, crystals, mucus, bacteria or other germs.
• Chemical check: a dipstick, a thin strip with pads that change colour, shows substances such as glucose (sugar), protein, ketones, bilirubin (two other chemicals the laboratory looks for), blood and how acidic the urine is (pH).

Urine can range from nearly colourless to dark yellow, and some foods can tint it red. Some medicines can also change its colour without meaning anything is wrong, and your provider may ask you to stop medicines that could affect results ^[1].

4. How to give a clean catch sample

Your provider will say which type of sample is needed. Two common types are a clean catch sample and a 24-hour collection ^{[1, 3]}. For a clean catch, which is a midstream sample, MedlinePlus describes these steps ^{[2, 3]}:

1. Wash your hands.
2. Clean the genital area with the wipe provided.
3. Start to urinate into the toilet.
4. Move the container into the stream and collect the middle part of the urine.
5. Finish urinating into the toilet and close the container.

For a 24-hour collection, you are given a special container and instructions, because protein levels change through the day and this can give more complete results ^[3]. Tell your provider if you are menstruating or have bleeding piles (hemorrhoids), since blood from outside the urinary system can affect results ^{[2, 3]}.

No special preparation is usually needed. You should not stop any medicine unless your provider tells you to ^[2]. MedlinePlus states that there is no known risk to the test ^{[1, 2]}.

5. Understanding the results

Normally, glucose, ketones, protein and bilirubin are not found in urine, and blood cells and nitrites are not usually seen. Reference ranges vary a little between laboratories ^[1]. Abnormal results can be linked to kidney disease, urinary tract infection, kidney stones, poorly controlled diabetes, or cancer of the bladder or kidney, and so a provider must interpret them ^[1].

Blood in the urine

Blood in the urine is called hematuria. It can be visible or found only under the microscope. Many causes are not serious, such as some medicines, hard exercise or menstruation. Foods such as beets and rhubarb can also turn urine red without any blood being present. Other causes are more serious, such as infections, stones in the kidney or bladder, an enlarged prostate or cancers. It can signal a condition that needs treatment, so more testing may be needed ^[2].

Protein in the urine

Healthy kidneys keep most protein in the blood, so only a very small amount normally appears in urine. A large amount is called proteinuria and can signal kidney problems ^[3]. Temporary rises can follow strenuous exercise, dehydration, diet, stress or pregnancy. If levels stay high over time, it usually points to kidney damage from kidney disease or another condition, and more tests are needed to find the cause ^[3].

Other kidney tests

A urine albumin test looks for albumin, a protein that leaks into urine when the kidney filters are damaged ^{[3, 5]}. The CDC says a test called the urine albumin-to-creatinine ratio may be repeated once or twice to confirm a result ^[5]. Blood tests, such as creatinine and a calculated number called GFR that shows how well the kidneys filter, are used together with urine tests ^{[4, 5]}. Imaging, such as an abdominal ultrasound, may also be used ^[4].

6. Home test strips and self-care

Home dipstick kits for protein are sold without a prescription. They depend on matching colours to a chart, so you need to see colours accurately ^[1], and they can be accurate if you follow the instructions carefully ^[3]. It is wise to ask a provider which test suits you ^[3]. Long-term use of some pain medicines, such as NSAIDs, can harm the kidneys, so ask your doctor before using them regularly ^[3]. Tell your doctor about every treatment you use, including traditional and herbal products.

7. When to see a doctor

See a doctor if you notice blood or foamy urine, pain when you pass urine, passing urine much more or less often, back or belly pain, swelling in the hands, feet or eyelids, ongoing tiredness or nausea ^{[2, 3]}. Also speak to a doctor if you have diabetes, high blood pressure, heart disease or a family history of kidney failure and have not had your kidneys checked ^[4]. Ask for your results to be explained if a report shows anything outside the usual range.

Seek urgent help for severe pain in your side or belly, fever with shaking chills, or inability to pass urine.

In an emergency, call your local emergency number (112 in India, 911 in the United States).

8. Conclusion

A urine test is a simple, painless check that can reveal early signs of problems in the kidneys, bladder and body chemistry. Giving a careful clean catch sample helps the result be accurate. Many abnormal results have harmless causes, and others need further tests, so the next step is always a conversation with your doctor.