TB - Is the PCR the Best Test?

So we've kind of the smears are negative, plus the two PCR's are negative. So I would say like TB, active TB is now less likely. Then we still have to figure out why this patient is symptomatic. We can have serologic studies, potentially other sputum evaluation or doing a more invasive testing like bronchoscopy. And then the most invasive testing being something like a lung biopsy where we're not looking at just the sputum but actually the lung tissue itself.