[Phlogiston]

Make SURE that your tube tester is putting out at least 2.5V when testing these tubes (especially the 245) most testers are calibrated around 6.3 or higher settings and sag at 2.5V. The old story that the manufacture and/or  expected results (Mhos) are designed to make up for that is B.S. - sorry.

I will often insert my VOM probes into another sockets (big pins) while doing these tests to actively monitor voltage. A lot of good tubes have been thrown away - - 

Russ

P.S. TIP - I set my 533 on 3V for these tubes and I get about 2.5 on the filaments - Saves me time, might work for you, just need to check.