Laboratory tests
One or more laboratory tests are performed to confirm the presence of RCC.
Urinalysis
More than half of all patients with RCC have blood in the urine (hematuria). Often this blood is present in small amounts or diffused in the urine so that it cannot be seen with the naked eye (called microscopic hematuria). To detect hematuria, a chemical test of the urine is performed. On occasion, cells found in the urine are examined under a microscope for abnormalities. This procedure is called urine cytology.
Blood tests
Another laboratory procedure typically used in the diagnosis of RCC involves microscopic examination and/or chemical analysis of the patient's blood. These tests screen for the following conditions which may indicate the presence of cancer:
- Anemia (too few red blood cells; caused by internal bleeding, a common cancer symptom)
- Polycythemia (too many red blood cells; sometimes caused by cancerous tumors in the kidney that trigger the release of erythropoitin [EPO], a hormone that increases red blood cell production in bone marrow)
- Hypercalcemia (high blood calcium levels) and elevated liver enzymes
Cystoscopy
Blood in the urine can result from other health problems, such as kidney stones or traumatic kidney injury, so the doctor may order a cystoscopy to determine precisely where the internal bleeding is occurring. In cystoscopy, a long, thin, rigid or flexible optical scope is inserted through the urethra and into the bladder. The practitioner then makes a visual examination of the urethra, bladder, and kidneys to locate the site of bleeding.
Fine needle aspiration
RCC tumors are made up of cancerous (malignant) cells that grow into a mass. If a tumor is found through imaging or other procedures, a cell sample may be taken for microscopic examination.
Physicians usually avoid performing needle biopsies of suspected kidney tumors because of the risk for bleeding or other complications. Some tumors contain a fluid-filled cyst. A small amount of this fluid can be drawn out of the cyst for examination by a pathologist, who will look for and identify the cancer cells. This can help the physician determine an appropriate treatment plan. While no longer common, a similar technique can be used to collect a sample of solid tissue from a noncystic tumor.
Physician-developed and -monitored.
Original Date of Publication: 10 Jun 1998
Reviewed by: Stanley J. Swierzewski, III, M.D.
Last Reviewed: 01 Dec 2007
Kidney Cancer, Laboratory Tests reprinted with permission from urologychannel.com
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