It’s such a common routine in a doctor’s office or clinic or hospital that patients tend to comply without thinking: Step on the scale, roll up your sleeve for the blood pressure cuff, urinate into a cup.

But that last request should prompt questions, at the least. The urine test is the first step into what’s sometimes called “the culture of culturing.”

In patients who have none of the typical symptoms of a urinary tract infection — no painful or frequent urination, no blood in the urine, no fever or lower abdominal tenderness — lab results detecting bacteria in the urine don’t indicate infection and thus shouldn’t trigger treatment.

Older people, and nursing home residents in particular, often have urinary systems colonized by bacteria; they will have a positive urine test almost every time, but they’re not sick.