Almost 100 people turned up for a blood test to help a family's search to find a bone marrow donor for a six-year-old Northamptonshire girl.
Caitlin Behan, from Weston Favell, has Fanconi's anaemia, a potentially fatal disease, which prevents the bone marrow from producing blood cells normally.
The only hope of a cure for the rare condition is a bone marrow transplant.
The latest testing session, at Daventry Fire Station on Tuesday night, was the fourth public surgery in the search for a suitable donor.
Blood samples were taken from 90 potential donors.
Detective Inspector Neil McMahon, from Northampton CID, a friend and work colleague of Caitlin's father Sergeant Mark Behan said: "Considering the relatively small size of Daventry town, compared to Northampton where we have held previous surgeries, we consider this to have been a good turnout.
"We would like to pass on our thanks to everyone who turned up for a blood test, and also Northamptonshire Fire and Rescue Service, the voluntary blood takers and police officers and staff from the Anthony Nolan Trust who made the session possible."
Caitlin has a rare tissue type which is proving an obstacle to finding a match and more testing sessions have been planned for next month.