I'm not trying to start a USA bash, but I'm pretty sure cost of those bloods is not $600. If you wanted into a clinic and asked for a cash price I'm pretty sure it would be lower. I base this claim on looking at medical bills in a far away country with an utterly different system.
At the same time, the blood draws for this study are looking for things your average clinic isn't going to do for a walk in. And unlike the system in the U.S., or another country, this isn't being done for the patient's health specifically, but rather for research, so there is no subsidy, either from insurance or the government health system.
Basically, we have no idea how much it would cost.