Most lenders require that you have a middle credit score of at least 640 for FHA and USDA loans.
I can go down to 620 on USDA but it will depend on what your recent credit history looks due to USDA's guidelines. The medical collections do not affect your eligibility but the certainly will affect your credit scores.
If I can be of further assistance please do not hesitate to contact me.
ReMax Mountain Properties
1151 US Highway 64 West
Murphy NC 28906