Serial kidney function and urine protein determinations are appropriate for this young patient with asymptomatic microhematuria. The evaluation of asymptomatic hematuria is somewhat different in younger patients as compared with older patients. In the former, hematuria is likely from mild glomerular disease (such as IgA nephropathy and genetic disorders such as collagen mutations). In older patients, structural changes, stones, infection, and cancers predominate. This young patient presents with asymptomatic microhematuria and has a family history of hematuria (without kidney failure) on her mother's side. Serologic and imaging studies are normal, there are no structural abnormalities of the kidney (such as kidney stones), and infection is unlikely based on the urinalysis. She likely has a familial hematuric syndrome, which is typically associated with either X-linked or somatic mutations of type IV collagen. In female carriers of X-linked hereditary nephritis (Alport syndrome), kidney failure may occur later in life. Thus, annual measurements of blood pressure, kidney function, and urine protein are reasonable (although there are no consensus guidelines defining the frequency of testing).

Cystoscopy is usually performed in patients with hematuria who are older than 35 years of age or who have risk factors for lower urinary tract malignancy (such as smoking, aniline dye, or cyclophosphamide exposure). This patient is at low risk for urinary tract malignancy and therefore does not have an indication for cystoscopy or urine cytology. Similarly, an abdominal CT could identify a renal malignancy that might have been missed on kidney ultrasound, which is not indicated in this young patient.

A kidney biopsy is often performed in a patient with unexplained abnormalities on urinalysis (such as hematuria or proteinuria) in the presence of evidence of kidney failure in order to establish the diagnosis and guide therapy. However, this patient has normal kidney function and stable microhematuria without other clear risk factors for progressive kidney disease. Therefore, kidney biopsy is not currently indicated.

The American College of Physicians has provided high-value care advice regarding the evaluation of hematuria and considerations for urologic referral and is available at Annals of Internal Medicine (Nielsen et al, 2016).