I came across Walk-In-Lab by accident
I'm glad I did. I am uninsured and contacted LabCorp for blood work. They quoted me $836. For the same exact tests, Walk-In-Labs quoted me $385 (after some online discounts). Walk-In-Lab ended up outsourcing the labs to LabCorp and Quest Diagnostics (in my case) anyway. So I made an appointment with LabCorp. I was emailed any special instructions (fasting, in my case), the lab order, and the appointment. I was told to bring the lab order, but LabCorp didn't need it. I was already in their system. I think all they asked during check in was how I was paying? The option I chose was that I was paying through a third party. It was all an easy process.
