A young woman complained that urinating was painful, and she was running frequently to the bathroom.
That sounded like the common bladder infection, my favorite disease. It’s one of the infections that antibiotics treat, and patients usually feel better within a day. Everyone is pleased.
After arriving in the room, I asked for a urine sample and took a dipstick from a bottle I carry. It can detect sugar and blood and protein and half a dozen other substances in urine, but in this case I was looking for white blood cells (a sign of infection) and leukocyte esterase, a chemical that bacteria produce. Both tests were negative. What was going on? Her story and all the evidence pointed to a bladder infection.
Every medical student learns to treat the patient, not the test. The test showed that she didn’t have a bladder infection, but I disagreed, and I turned out to be right.