Sensitivity of liquid biopsy - 1271995

Hi,

Viewed the GRACE video on liquid biopsy. It sounds like a preferred method than tissue biopsy. With any laboratory test, I would imagine there is a possibility of false positive and false negative.

In my simplistic view, the more of what one hopes to detect through the blood sample the more likely of detection and vice versa. If there is evident of progression through many locations, I would think there is higher likelihood of detecting T790 mutation and fewer locations of progression, less likelihood of detecting T790 mutation.

How sensitive is the liquid biopsy to detect T790 mutation?

Is the prevailing practice to use liquid biopsy as the first line of T790 detection?

Thx