A technical problem with a diagnostic machine in Cranbrook, British Columbia, switched thousands of test results for chlamydia and gonorrhea to their opposites, said Alison Paine, spokesperson for the Interior Health Authority. "In other words, if you were a positive, you would have received a negative reading. If you were a negative, you would have received a positive reading," said Paine. About 3,000 people are believed to have taken the tests between Nov. 1, 2000 and May 24, 2002.

Paine said the company that manufactures the machine notified the authority in July of the defect. "We immediately stopped using the machine," said Paine. Becton, Dickenson and Co., based in New Jersey, manufactures the BD ProbeTec. A spokesperson was unavailable for comment. Only two machines out of 1,000 tested worldwide have shown the defect - incorrectly installed optical bundles - according to the company's Web site product notice. The company said it is working with Health Canada to ensure the machine is recalled.

About 83 of those tested during the time were given a clean bill of health when they had one of the diseases. The rest were told they were infected and were given treatment when they did not have the diseases, said Paine. The number affected multiplies when considering that each of those tested had at least one sex partner to whom the results also mattered. Most of the 83 have been contacted, Paine said, but not all. She urged them to telephone 1-888-887-8811 for treatment.

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