Microhematuria: Implications of an Unexpected Finding

If a small to moderate amount of isolated microscopic hematuria is detected on a routine urinalysis in a non-smoking patient younger than 40 or 50 years, is a workup for bladder cancer still warranted? Also, what role should the new NMP22 test play in bladder cancer screening in adults? Is further testing needed if the results of an NMP22 test are negative?

— Larry Novik, MD
  Fairfield, Conn

Although the incidence of bladder cancer in non-smoking asymptomatic women under age 40 years who have not been exposed to environmental/occupational carcinogens is extremely low, current standards still recommend cystoscopy. Cystoscopy is probably warranted in smokers or former smokers of any age—and in men (bladder cancer is roughly 3 times more common in men than in women).

Even small amounts of microhematuria should not be "overlooked." The degree of detectable hematuria does not correlate with the seriousness of its underlying cause.

In several large studies, the sensitivities of NMP22 (and NMP22 Bladder Chek)—particularly for well and moderately differentiated cancers—were less than 50%.^1,2 The sensitivity of the tests for non–muscle-invading (earlier) cancer was also 50% or less.^1,2 Thus, the current NMP22 tests do not obviate the need for cystoscopy in a standard hematuria workup.

— Edward M. Messing, MD
  Winfield W. Scott Chair of Urology
  Professor of Urology and Oncology
  Deputy Director of the University of Rochester Cancer Center
  University of Rochester
  Rochester, NY