I'm not willing to do a DNA test and have that floating around out there (tinfoil hat).
But, I've seriously considered picking up a $230 combo blood tester that also does lactic. Not sure I could convince the wife to take samples though during a test. Lol!!!!! "You want me to do WHAT while you ride?"
Is the ear the only way?
I guess for now ramp/ftp tests and looking for that 'inflection' point in the HR is going to be the best bet.