How can a healthcare provider determine if a patient has drug-resistant TB?

To determine if a patient has drug-resistant TB, drug susceptibility testing is the most definitive method. This process involves performing tests on a sample of the bacteria that are causing the infection to assess which antibiotics are effective against it. The results will show whether the strain of Mycobacterium tuberculosis is resistant to any of the standard TB medications, which is crucial for guiding treatment decisions.

While observing patient symptoms can provide initial insights into the patient's condition, it is not reliable for determining drug resistance, as symptoms of drug-resistant TB can resemble those of non-resistant forms. Similarly, standard laboratory tests can help confirm the presence of TB but do not specifically assess the susceptibility of the bacteria to drugs. Asking about previous treatments may provide some context, but alone it does not yield definitive information about current drug resistance. Therefore, drug susceptibility testing directly measures the resistance and is the accepted and necessary approach for diagnosing drug-resistant TB.