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If you see visible blood in your urine, get checked once, even if it doesn't hurt and even if it's gone by the next day

  • Moderate value
  • Evidence B
  • Buys life
  • Costs a little
  • Takes some hours
  • No willpower

In plain words

For someone over 60 who sees visible blood in the urine once, the chance that bladder cancer is eventually found is about 2.8%; for ages 40 to 59 it is about 1.2%. That is not high, but it is high enough that you must get checked once. Get checked even if the bleeding stops the next day.

Cost

A urinalysis costs a few dozen CNY and a urinary tract ultrasound one or two hundred. If the doctor thinks it's needed, a cystoscopy adds about a thousand CNY.

What you get

A study in the U.K. used electronic records from community general practice (primary care), with 4915 bladder cancer cases against 21718 controls. Among people who had visible blood in the urine, the share in whom bladder cancer was eventually found was 2.8% for those over 60 (95% CI 2.5 to 3.1, the plausible range) and 1.2% for ages 40 to 59 (95% CI 0.6 to 2.3). This share is technically called the positive predictive value. Blood that can be seen only under a microscope is also meaningful. The odds ratio was 20 (95% CI 12 to 33). For people over 60 this share was 1.6% (95% CI 1.2 to 2.1).

Notes

“It doesn't hurt” is the key point. Blood from stones and infections usually comes with cramping pain in the flank or abdomen, or with frequent, urgent or painful urination. Blood from a tumor often comes with no sensation at all and stops for a few days before coming back, which is how many people let it go. Taking blood thinners is not a reason to skip the check. After intense exercise, or around a woman's period, you can recheck once first and then decide. The benefit is rated “small” because there is only a detection rate, with no effect size for how much earlier checking lowers deaths.

Evidence grade
B : Supported by research but without a precise number, or based on small or single studies.
Sources
  1. Price SJ, Shephard EA, Stapley SA, Barraclough K, Hamilton WT (2014). Non-visible versus visible haematuria and bladder cancer risk: a study of electronic records in primary care. British Journal of General Practice, 64(626), e584-e589. https://doi.org/10.3399/bjgp14X681409

Mentioned in

Translated from the Chinese original. Original book, section 1, tip 27. This section is about health and medicines. It is general information, not a substitute for a doctor’s diagnosis or prescription. Content may be out of date and rules differ by place. When you actually deal with an agency, a doctor or a court, follow what local officials, doctors and lawyers tell you. Disclaimer