Tuberculosis diagnosis from sputum using Raman spectroscopy

Tuberculosis (TB) is a deadly disease that causes 1.4 million deaths per year. It is crucial to diagnose and isolate TB patients in the early stages to control this contagious disease. The current gold standard test for TB detection is the culture of a patients' sputum. Although the culture test provides fair accuracy, it takes days to weeks to produce results and needs trained laboratory personals. Here, we demonstrate an optical sensor that uses Raman spectroscopy to detect TB via sputum samples. We collected and prepared sputum samples of potential TB patients in a controlled environment, conducted culture tests, and labeled them as TB-positive and TB-negative samples. We then acquired Raman spectrums of the prepared samples using a 785 nm laser spectroscopy setup, employed principal component analysis (PCA) on the spectroscopic data, and found TB-related unique features which form the basis of TB diagnosis. To evaluate the sensor performance, we tested 40 TB patients, of which 17 were TB-positive and 23 TB-negative. The sensor judiciously classified the two groups with an accuracy of 95%. The proposed sensor is a step towards a rapid, non-invasive, technician-free, and portable TB diagnostic point-of-care device.