A look at tests performed on the quarantined tuberculosis patient

Tests performed on a man isolated with what was believed to be an extensively drug-resistant form of tuberculosis now show no sign of the strain, XDR TB. Here is a look at the various tests done:

_ In March, tests on a sputum sample from a bronchoscopy performed on Andrew Speaker at an Atlanta hospital showed he had multidrug resistant tuberculosis, or MDR TB.

_ On May 22, the federal Centers for Disease Control and Prevention, which tested the same sample, found it contained XDR bacteria.

_ A subsequent CDC test of bacteria from the same sample showed MDR bacteria, not XDR.

_ On Tuesday, Denver's National Jewish Medical Center said that three other samples were taken from Speaker _ on April 25 in Atlanta, on May 27 in New York and on June 1 in Denver. Its tests on all three samples, using three methods, showed no sign of XDR. The CDC repeated and confirmed those results.

_ National Jewish is also testing a subculture from the March sample that first yielded XDR. Those results are pending.