Testing of more than 3,000 people who may have been infected with hepatitis C at a New Hampshire by an alleged "serial infector" was canceled this weekend, leaving some former patients scared and angry. Health officials cancelled the weekend testing clinic, even though they asked the former patients at Exeter Hospital to get tested, because they said the logistics were too much. David Kwiatkowski, a former lab technician at Exeter Hospital, was indicted last week for allegedly infecting 31 people with hepatitis C at that hospital, but might have infected thousands of patients in at least 13 hospitals where he has worked.