Mark Oren, M.D., FACP
Urine tests are used to help diagnose many different conditions, including cancer. Urinalysis is a physical, chemical and microscopic examination of urine using a battery of tests. The primary urine test related to cancer is urine cytology, which primarily looks for cancer and inflammatory diseases of the urinary tract. Other urine tests may be used to search for blood in the urine (hematuria), which can indicate the presence of cancer or less serious conditions, such as an infection.
Urine testing also may be used to detect tumor markers in individuals. Tumor markers are substances released in the urine, blood or tissue in response to cancer cells. Research is examining which cancers can be detected and monitored by tumor markers found in urine.
Patients can collect a sample of urine either at home or in a physician’s office. The procedure for obtaining a sample is easy and painless. The sample is then sent to a laboratory for analysis by a pathologist, who will look for abnormal cells that may indicate the presence of an abnormal condition or disease. In some physician offices and facilities, simple urinalysis can be completed on site.
Though urine tests can suggest or indicate the presence of cancer, the condition must be confirmed by additional tests, such as a biopsy or a blood test. If cancer is confirmed, the patient may receive one or more of many different types of treatment, including:
- Radiation therapy
- Hormone therapy
- Biological therapy
About urine tests
Urine tests are used to detect a variety of illnesses from simple infections to more serious conditions, such as cancer. Patients obtain their own sample of urine and give it to a physician or other healthcare worker. Depending on the purpose and complexity of the test, the sample is analyzed either on site or sent to a laboratory.
A test called urine cytology (study of cells) is used to detect cancer and inflammatory diseases of the urinary tract. It is sometimes ordered when an x-ray of the bladder reveals suspicious lesions, or when an individual is at high risk for developing bladder cancer.
Blood in the urine also may indicate many different types of cancer, including those of the bladder, prostate, kidneys and urethra.
Sometimes the blood is visible, but more often it can be detected only by a microscope. Blood in the urine can be the result of many different illnesses and does not necessarily indicate that a patient has cancer. It is far more common for benign (noncancerous) conditions such as an infection to be the cause of blood in the urine.
Urine tests are used to diagnose a variety of cancers. These include:
- Bladder cancer. Urine cytology is the test most commonly used to test for cancer and inflammatory diseases of the urinary tract. The cancer is revealed by the presence of the tumor marker telomerase, an enzyme active in malignant (cancerous) cells. Urine cytology is very effective for detecting high-grade bladder cancers. It can also be performed on bladder washings, in which samples are taken by placing a salt solution into the bladder via a catheter. The solution is then removed and tested.
The U.S. Food and Drug Administration (FDA) has approved two urine tumor marker tests that can be used to diagnose bladder cancer that has recurred after treatment. The BTA test looks for proteins in urine that may indicate the presence of recurrent cancer cells. The NMP22 test measures the protein level in the nucleus of bladder cancer cells.
- Both of these tests are less specific, which means they may produce false positives that indicate that cancer is present when in fact it is not. Researchers are investigating other tumor marker tests that involve urine samples. Urine tests may reveal blood in the urine, which is another possible sign of bladder cancer.
- Kidney cancer. About half of all patients with kidney cancer have blood in their urine. In addition, urine cytology can be used to detect cancer cells in the urine. It is more likely to detect transitional cell carcinoma, a less common kidney cancer that develops in the lining of the renal pelvis, ureter or bladder) than renal cell carcinoma.
- Prostate cancer. Blood in the urine is one possible sign of prostate cancer. In addition, thymosin beta-15 is a tumor marker for prostate cancer that can be found in urine. The combination of a urine test for thymosin beta-15 and a blood test for the tumor marker prostate-specific antigen (PSA) has been found to increase accuracy in diagnosing prostate cancer.
- Multiple myeloma. Cancerous plasma cells make an antibody that collects at high levels in the urine. Abnormal antibodies may indicate a plasma cell tumor.
- Neuroblastoma. When nerve cells communicate with each other, they release chemical neurotransmitters known as catecholamines. These substances break down into smaller pieces called metabolites and are passed out of the body in urine. Neuroblastoma cells release two catecholamine metabolites that are often measurable in urine, indicating cancer. They are homovanillic acid (HVA) and vanillylmandelic acid (VMA).
- Certain endocrine system cancers. Many diseases including pituitary tumors and adrenal cancer can cause the adrenal glands to produce excess hormones. A 24-hour urine test may be used to measure the amount of hormones produced in a day.
- Gastrointestinal carcinoid tumors and lung carcinoid tumors. Carcinoid tumors often produce excess levels of serotonin, a hormone-like substance. This is especially true of tumors that originate in the small intestine. Serotonin is broken down into a substance called 5-hydroxyindoleactic acid (5-HIAA), which is then released in the urine and can be detected in testing.
- Pancreatic cancer. At least half of people with pancreatic cancer develop jaundice, which causes the pigment bilirubin to accumulate in urine. A urine test can detect bilirubin. However, many other diseases, including hepatitis, can cause jaundice.
Types and differences of urine tests
There are many types of urine tests that can be used to detect and monitor cancerand other diseases and conditions. These tests include:
- Tumor marker tests. Urine tests and blood tests can detect certaintumor markers, which are substances that can be made by cancer cells and normal cells.
- Other types of urine cytology. Examination of the cells can reveal blood in the urine, hormones and other substances that may indicate cancer.
- Nitrite test. Nitrite is normally not detectable in the urine. Nitrite is formed when bacteria changes nitrate in the urine into nitrite. The presence of nitrite in the urine (nitrituria) is often a sign of a urinary tract infection.
- Urine specific gravity test. Measures the concentration of the urine. Abnormally increased or decreased urine specific gravity may indicate a kidney disorder.
- Urine pH test. Measures the pH (acidity) of the urine. A high level of urine pH may indicate a kidney disorder, including kidney failure.
- White blood cell test. Checks urine for the presence of white blood cells. The main infection-fighting cells in the body, white blood cells are not normally detectable in the urine. The presence of white blood cells in the urine may indicate a urinary tract infection.
- Microalbuminuria test. Detects albumin, a protein that prevents fluid from leaking out of blood vessels. Albumin also nourishes tissues and transports vitamins, hormones, drugs and ions throughout the body. Protein is not normally detectable in urine. The presence of protein in urine, or proteinuria is often an early sign of kidney disease.
- Creatinine test. Measures the amount of creatinine in the urine. Creatinine is a waste product removed from the body by the kidneys. Abnormal amounts of creatinine may be a sign of kidney damage.
Before and during the urine test
Most urine tests require little or no preparation. The physician may instruct the patient to restrict exercise and to reduce or stop taking certain medications or vitamins at some point prior to the test.
Many urine tests involve only a spot (single) sample. Patients will obtain their urine sample either at home or in a physician’s office or clinic. Patients will receive a cup or other container that they will take into the bathroom. To capture a sample of urine, patients should try to obtain the specimen in midstream, a technique known as “clean-catch.” Preparation for this technique differs depending on the patient’s sex:
- Males. Wipe clean the head of the penis.
- Females. Wash the area between the lips of the vagina with soapy water and rinse well. If the sample is being collected in a physician’s office or clinic, cleansing wipes may be provided to use before collecting the urine.
Patients should not use the first sample upon awakening, but should instead wait to take a later sample. At least three hours should expire between the previous void and the urination used for obtaining the sample. As patients start to urinate, they should let a small amount of the initial urine fall into the toilet bowl. This will help clear the urethra (canal through which urine is discharged) of contaminants. Using a clean container, patients should capture between 1 and 2 ounces (30 to 60 milliliters) of urine before removing the container and finishing urinating into the toilet bowl. The contained should be tightly capped, being careful not to contaminate the inside of the container during the process.
After patients have washed, they should give the container with the sample to a healthcare provider. The container should be marked with the patient’s name, date of collection and any other pertinent information requested by the provider.
When obtaining a sample from an infant, an adult should prepare the child by washing the area around the urethral opening. Because infants cannot give voluntary samples, parents will have to rely on a urine collection bag to obtain the sample. This is a plastic bag with an adhesive paper on one end. For boys, the bag is placed over the penis and the adhesive is attached to the skin. For females, the bag is placed over the labia. The child then wears a diaper over the bag.
The child’s caregiver will need to check frequently to see if the infant has urinated into the bag. After the urine has been obtained, the bag is gently removed from the genitals. The urine is poured into a container and brought to a healthcare provider. Care should be taken not to contaminate the sample when it is being transferred into the container.
Some urine tests, such as for pituitary tumors, require a 24-hour sample rather than a spot sample. To collect a 24-hour urine sample the patient should:
- Get up in the morning of the first day of the test and empty the bladder. The urine should then be discarded in the toilet.
- Collect all subsequent urine in the provided container for the next 24 hours.
- Cap the container and keep it in a refrigerator or cool place during the collection period.
- Get up in the morning of the second day of the test and urinate into the container.
- Return the labeled container to the physician’s office or a laboratory for analysis.
After the urine test
It typically takes two or three days for a laboratory to complete a detailed urinalysis. A pathologist will use a microscope to examine the sample for epithelial cells (which make up the membranous tissue covering internal organs and other internal surfaces). These line the urinary tract and are shed into urine.
The presence of abnormal epithelial cells may indicate cancer of the kidney, ureters (long, narrow ducts that convey urine from the kidney to the urinary bladder), bladder or urethra. A pathologist will also look for other indicators of disease in the urine, such as excessive numbers of red blood cells, white blood cells or other abnormal cells.
Tumor marker tests may take longer to complete due to the complexity of the process. In general, elevated levels of tumor markers can indicate the presence of cancer. However, they can be elevated in people with noncancerous disease. The mere presence of abnormal cells or tumor markers is not enough evidence to make a cancer diagnosis. Instead, the results must be confirmed by additional testing, such as a tissue biopsy, blood test or imaging test.
Treatments that may follow urine tests
Patients who are diagnosed with cancer may be treated in many ways. In some cases, only one form of treatment will be considered. However, in most cases, a combination of treatments will be used to fight the cancer. Commonly used treatments include:
- Chemotherapy. Uses one or more powerful drugs to target dividing cancer cells. The drugs work to destroy the cells to prevent reproduction and metastasis throughout the body.
- Radiation therapy. Uses an energy called ionizing radiation to kill cancer cells and shrink tumors. Radiation targets dividing cancer cells and disrupts or destroys their genetic material, preventing the cells from continuing to grow and spread throughout the body.
- Biological therapy. Repairs, stimulates or enhances the immune system so that it can better recognize and destroy cancer cells. In some cases, biological therapy directly attacks cancer cells. This therapy is also used to curb the side effects associated with cancer treatments such as chemotherapy.
- Hormone therapy. Treatment for cancers that depend on hormones to grow and spread. Patients who undergo this treatment sometimes take medications that reduce the levels of certain hormones, such as estrogen and testosterone. In other cases, patients may take drugs that prevent cancer from attaching to hormones that help the disease to thrive.
- Surgery. Used for the complete or partial removal of a tumor.
- Bone marrow transplants. Replace bone marrow damaged by cancer or cancer treatments with healthy marrow obtained from a donor or the patients themselves. Bone marrow contains stem cells that produce red blood cells, white blood cells and platelets necessary for life.
Questions for your doctor about urine tests
Preparing questions in advance can help patients have more meaningful discussions with their physicians regarding their conditions. Patients may wish to ask their doctor the following questions about urine tests:
- What type of urine test do I need?
- Can I collect the sample at home?
- Do I need any preparations before I collect the sample?
- Do I need to collect the sample at a specific time(s)?
- Do you need more than one sample?
- What type of analysis will be conducted on this sample?
- Are there any tumor markers associated with my suspected cancer?
- What kind of conditions can be diagnosed with this urine test?
- What does it indicate if I see blood in my urine?
- When and from whom can I expect to receive the results of the test?
- Can I use a home version urine test for my condition?
- If you suspect cancer, what will be the next step?