A device used to test for exposure to tuberculosis is being recalled by the health department after it left metal splinters in the arms of six children. The equipment, called a heaf head, delivers a six-point pin prick in the arm. The test is given to children aged 13 to 14 before vaccination against TB. Around 720,000 heaf heads are issued every year. The Department of Health said there had been six reported incidents of splinters across the country. In all cases the splinters were detected soon after the tests and were quickly removed.