How to check a fuse in a live circuit?

If the fuse in a PCB, and the circuit is energized, how do i know if the fuse is good or blown?

I generally know that in order to check a fuse, i use the Digital Voltmeter and do continuity test.
But how about a fuse in a PCB board, how can i do that?
Update: and i can't take the fuse out.
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