"Demand to be tested"

A radiation oncologist is giving this tidbit of advice to patients exposed to polluted water in Massachusetts:

Sacher urged people exposed to Nyanza to get regular checkups and seek medical care whenever they have symptoms that seem unusual or last longer than expected, like a cold or respiratory problem lasting more than a week. They should also demand tests if they are worried, even if a doctor doesn’t think it is necessary, Sacher said.