How is blood in urine diagnosed?
The evaluation for blood in urine consists of taking a history, performing a physical examination, evaluating the urine with a chemical test strip and under a microscope, and obtaining a culture of the urine to identify any bacteria present. Lower urinary tract symptoms, such as urgency (feeling a strong need to urinate) and frequency (needing to urinate frequently), as well as the presence of fever or chills, are suggestive of infection. Recent trauma, even if believed by the patient to have been inconsequential, should be considered as a potential cause. Abdominal or flank pain, especially if radiating to the inguinal or the genital area, may suggest ureteral or kidney stones. All recent medications, including vitamins or herbal supplements, should be reviewed with the health-care professional. However, it is important to note that even if the patient has been taking a medication that is associated with bleeding, a full workup (as listed below) should still be undertaken.
The physical exam will focus on possible sources of hematuria. Bruising over the back or abdomen may indicate trauma. A digital rectal exam should be performed, especially in males, as findings consistent with prostatitis (for example, tenderness on palpation of the prostate) or an enlarged prostate suggestive of benign prostatic hyperplasia (BPH), may be useful in making a diagnosis. The finding of a nodule or an area of induration of the prostate may be indicative of cancer. A repeat urinalysis, as well as a urine culture, should be obtained. The presence of white blood cells on urinalysis is more consistent with a urinary tract infection. Protein, glucose, or sediment in the urine may indicate the presence of a disease of the kidneys. Blood tests are also important, as they will aid in assessing renal function and identifying any clotting abnormalities.
In addition to the basic history and physical exam, there are three additional components for any workup of hematuria: imaging, urine cytology, and cystoscopy.
The CT scan is an imaging evaluation of the urinary tract. Prior to the procedure, the patient drinks an oral contrast agent and a dye is injected intravenously. The patient then goes through the CT scan machine and images are taken of the abdomen and pelvis. Another test that can be performed, the intravenous pyelogram (IVP), is also a type of X-ray evaluation of the urinary tract. In this procedure, a dye is injected into the veins, and this is filtered by the urinary tract. A series of X-rays are then taken over a 30-minute period to look for abnormalities. The CT scan is more commonly performed than the IVP to evaluate the urinary tract and should be considered the test of choice. Both of these studies are especially useful for evaluating the kidneys and ureters, but not the bladder, prostate, or urethra. Therefore, a second examination called a cystoscopy is necessary. This is a simple 10-minute procedure using a thin, flexible cystoscope (or fiberoptic camera) is inserted via the urethra into the bladder to directly visualize any lesions or sources of bleeding. This is usually done with local anesthetic jelly injected into the urethra. Finally, urine cytology involves giving a urine sample to be analyzed by a pathologist for the presence of cancerous or abnormal-appearing cells.