More than 200 people who were tested for breast cancer in Gatineau, Que., will have to be retested, CBC News has learned.

Four Quebec hospitals have been told that they didn't follow proper procedures when they conducted about 2,100 tests between April 2008 and June 2009.

At Gatineau's Hull hospital, 110 tests will have to be redone and at the Gatineau hospital, 172 tests will have to be performed again, said Céline Jacob, who speaks for the Outaouais health agency. Altogether, 202 people will have tests redone.

Quebec's Ministry of Health requires hospitals to have lab procedures tested against external quality controls, but those controls weren't in place at the four hospitals that have been identified.