Hematuria – Blood in the Urine (Red Blood Cells)

If hematuria is detected at a screening evaluation by testing the urine with a “dipstick” during a routine health assessment, it is rarely associated with significant disease of the urinary tract. The dipstick is extremely sensitive, and this finding should be confirmed by formal examination of the urine under a microscope (hospital or commercial laboratory urinalysis). Evaluation of your child’s urinary tract is not necessary unless the dipstick finding is confirmed by microscopic urinalysis and is persistent (several specimens over a period of weeks). Assuming that this is the case, there are several diagnostic considerations.

Hematuria that derives from the kidney tissue itself, due to disease of the blood filtering units that make urine (nephritis, an inflammation of the kidney tissue) is almost always accompanied by protein in the urine (also detected by the dipstick). In addition, most types of nephritis are characterized by episodes of “gross” hematuria; the number of red blood cells is so large that the urine appears brown or tea colored to the naked eye. Nephritis may also be familial or hereditary. If any of these conditions are present in your child, blood tests and often a kidney biopsy are necessary to establish an accurate diagnosis.

Hematuria that derives from the urinary drainage system can be caused by kidney stone, cyst, partial blockage or birth defect of the urinary tract. All of these conditions can be evaluated by ultrasonography of the kidneys and bladder.

Particularly in those with a family history of kidney stone(s), excessive urine calcium (the most common reason to form stones) may be a reason for either gross or microscopic hematuria. This is an isolated finding (all other aspects of kidney function are perfectly normal), and only means that your child may be at risk for forming kidney stones in the future. The diagnosis is made by measuring the amount of calcium in a 24 hour urine collection, if a screening urine sample is suggestive of this condition. Therapy consists of increasing fluid intake to increase urine production in order to “wash out” calcium before it can crystallize and form a stone. Other therapies may include dietary adjustment and medication.

For the vast majority of children and adolescents with screening microscopic hematuria, the above evaluation is generally sufficient to diagnose any important conditions of the urinary tract which require further investigation. While a specific reason for screening microscopic hematuria is usually not found, this finding disappears in most, and we recommend only regular surveillance urinalyses to monitor for proteinuria. Of course, should your child have an episode of gross hematuria and/or manifest any complaints about urination, prompt re-evaluation is indicated.