In 2021, a total of 1.6M people died from TB, although it is a preventable and curable disease. Depending on susceptibility, TB is treated with a combination of several of 20 anti-TB drugs from the WHO treatment guidelines. Interindividual variability may result in toxicity or ineffective treatment. Therapeutic drug monitoring can be used to optimize dosing and treatment. However, several analyses may be needed, which is time consuming, expensive, and may result in needing multiple samples from a patient. Therefore, we aimed to develop a simple method to analyze all anti-TB drugs in one analysis. 

We developed an LC-MS/MS method in plasma, serum or saliva, allowing simultaneous analysis of 17 anti-TB drugs and 6 metabolites. The runtime of any combination of these 17 drugs only takes 1.7 minutes. We checked all standard parameters assuring the quality of our analysis and checked the expiry of the samples at different temperatures, allowing extrapolation to low income countries.  
With this method, we are able to analyze all first-line and most second-line anti-TB drugs, if processed immediately (e.g. pretomanid, delamanid, levofloxacin, moxifloxacin, gatifloxacin, bedaquiline, linezolid, tedizolid, clofazimine, ethionamide, prothionamide, rifapentine, and rifabutin) using a method that was validated according to the EMA Guidance.

 
In conclusion, we developed a method to analyze 17 anti-TB drugs simultaneously in one sample of plasma, serum or saliva: all first-line, BPaLM, and 9m all oral regimen for MDR/RR-TB drugs, and 63% of the longer MDR-TB regimen drugs. This method will save time and will further optimize therapeutic drug monitoring.