Tuberculosis blood testing kits used to detect activity are unreliable, according to the World Health Organization. It called for an immediate halt to the use of blood tests for detection of active tuberculosis, for they are faulty and leave the lives of millions of people at risk. Production of the test kits is largely in the hands of Western companies which export them to developing countries because they do not pass regulatory standards in such countries, WHO officials said. \"Overwhelming evidence showed that the blood tests produced an unacceptable level of wrong results,\" the U.N. agency said after year-long studies, \"They put patients\' lives in danger.\"