Our BioMed department checks our RPMs and timers quarterly, as required by NYS.  Should we be asking them to verify timers for every increment we use?  (ie 20sec AHG,  25sec IS, 45sec Wash)  Also, we found out they are just using their phones to check timer, not a validated stopwatch.

Thoughts?

As for how many points to calibrate, my personal opinion is to do three points.  The lowest should be below the lowest range you'll use, the highest above, and then a midpoint.  This is not perfect, but it helps prove linearity.  Many places only do one or two points, though.  It also depends on the significance of what you're measuring.  For instance, a 20-second AHG spin... does it really matter if it's 20.00001 sec or 20.00002?  Of course not.  That's what leads some people only to do one or two points.

When you say they're using their phone, do you mean a timer inside the phone?  I stick by my original statement above; it's irrelevant for what we do as med techs... but..., in this case, as your assessor / inspector / regulator, I will want to see that you are using a traceable device for these measurements.