https://www.cyclingnews.com/news/marine-worm-haemoglobin-could-be-the-new-frontier-of-blood-doping/

Apparently Arenicola marina lugworms have super haemoglobin.  And can live underwater or in air.  The haemoglobin has a half life of a few hours and so should be very hard to spot but I see an easy way to identify it.  Make the suspected swim two lengths of a pool underwater.  Let it be known that there will be a sharpshooter who will peg them if they surface.  ("Suspects A and C swam the distance and have been suspended for 4 years.  Sadly suspect B died of gunshot wounds but the good news was that he was determined clean.")