Figure 2: MALDI-TOF MS detection limit for MTB identification.

Genomic DNA extracted from M. tuberculosis H37Ra was serially diluted from 1000 to 5 copies in distilled water. The signal height was obtained using Type4 software. (A) Mass spectra of serial dilutions with various MTB copies. Positive signals are indicated by arrows. (B) Correlation between the diluted MTB copy number (theoretical copy number) and positive signal height from MALDI-TOF MS.