By Deja K. Hunt, MSN, NP-BC
The diagnostic process for microscopic or gross hematuria can be complex, as red blood cells (RBCs) can come from anywhere in the urinary tract, from the kidneys to the urethra/meatus.
According to the American Urological Association, microscopic hematuria is the presence of three or more RBCs per high-power field (HPF). Gross hematuria is blood in the urine that can be seen with the naked eye.
Glomerular causes of hematuria are from the kidneys themselves, which is the scope of nephrologists; urologists focus on a wide range of non-glomerular, pathologic and structural abnormalities throughout the urinary tract that can be seen on imaging.
Upper tract conditions like pyelonephritis, renal cell carcinoma (RCC), renal stones or ureteral strictures, and lower tract conditions like cystitis/UTI, BPH, prostate cancer and urothelial carcinomas can all be causes of hematuria.
The best first step is to run a formal microscopic urinalysis on a mid-stream, clean catch specimen, or one collected by sterile technique to avoid contamination from epithelial cells. A dipstick should ALWAYS be confirmed with a microscopic test as there is a much greater risk of false hematuria positives, which can be from free hemoglobin, antiseptics or myoglobin from exercise and dehydration.
The next step is to do a complete medical and surgical history to assess the onset of symptoms, medications taken, history of smoking, past chemotherapy or radiation, and risk for genitourinary malignancies and gynecologic conditions.
An important note: this comprehensive process should be the SAME for patients taking anticoagulant or antiplatelet medications. While these drugs may increase the duration and severity of hematuria, they do NOT cause the condition as a side effect.
In confirmed cases of hematuria, ordering a CBC, renal function tests, PT/INR and possibly a prostate-specific antigen (PSA) level for men – considering age and desire to test – will be helpful for specialists in advance of a referral.
Another useful tool for gross hematuria is a CT urography (CTU) or an MR urography (MRU) if a patient cannot have contrast dye. These scans provide a fuller view of the urinary tract anatomy than ultrasound and a better assessment of upper tract malignancies. A retroperitoneal ultrasound may be beneficial in lower-risk patients to evaluate renal masses and renal stones but cannot fully assess ureteral anatomy and all upper tract stones.
Urologists typically perform a cystoscopy to check for lower tract malignancies and, in cases of persistent gross hematuria, a urine cytology test or other tumor markers can be considered after a negative workup.
Patients who are at low risk for malignancy with an underlying condition like a UTI or gynecological condition will likely have a recheck of their UA after treatment before proceeding with other testing.
While hematuria patients tend to fear cancer, the issue is often benign and treatable with non-invasive options. The likelihood of malignancy in microscopic hematuria is less than 5% in the general population, but urologic disease is based on risk factors. Our job as physicians and advanced practice providers is to take all cases of hematuria seriously and order the appropriate diagnostic tests to begin resolving their root causes as quickly as possible.
Deja Hunt is a Nurse Practitioner with Urology of Virginia, based in its Virginia Beach office. urologyofva.net
