Hair isoniazid levels predict TB sputum culture conversion

This study investigated whether measuring levels of the anti‑TB drug isoniazid in hair can help predict how quickly people with pulmonary tuberculosis (TB) clear the bacteria from their lungs during treatment. Sputum culture conversion — when TB bacteria no longer grow in a laboratory culture of a person’s sputum — is an important milestone during therapy, but it usually takes 6–8 weeks and can delay treatment decisions. The researchers enrolled 56 people starting standard TB treatment and collected both hair and sputum samples at the start and during treatment. Hair samples were analyzed using sensitive laboratory techniques to measure cumulative drug exposure over time. The results showed that among participants with usable data, those who had higher median levels of isoniazid in their hair (about 0.05 ng/ml or more) by the end of the intensive phase of treatment (8 weeks) were more likely to have their sputum cultures turn negative, indicating that the TB bacteria were cleared from their lungs. By contrast, those with lower hair isoniazid levels tended to still have positive cultures. These findings suggest that hair levels of isoniazid reflect how well the drug has been taken and absorbed over several weeks and may help predict whether a person will respond promptly to TB therapy. This approach could be useful for monitoring treatment progress and supporting personalized care in settings where immediate culture results are not available.

Disclaimer: This lay summary was generated by AI and has not been approved by any of the authors yet.