| Nurse practitioner | 332 |
| Physician assistant | 225 |
| Family practice | 221 |
| Internal medicine | 135 |
| Certified Registered Nurse Anesthetist (CRNA) | 111 |
| Emergency medicine | 74 |
| Mass Immunization Roster Billers | 57 |
| Physical therapist (private practice) | 47 |
| Mental Health Counselors | 45 |
| Obstetrics/gynecology | 42 |
| Optometrist | 40 |
| Anesthesiology | 37 |
| General surgery | 37 |
| Ambulance Service Supplier, e.g., private ambulance companies, funeral homes | 33 |
| Diagnostic Radiology | 33 |
| Pediatric medicine | 32 |
| Orthopedic surgery | 28 |
| Ophthalmology | 25 |
| Neurology | 23 |
| Cardiology | 23 |
| Gastroenterology | 21 |
| Pulmonary disease | 21 |
| Licensed clinical social worker | 20 |
| Nephrology | 20 |
| Chiropractic | 18 |
| Urology | 18 |
| Podiatry | 17 |
| Pathology | 16 |
| Psychiatry | 14 |
| Centralized Flu | 14 |
| Clinical psychologist | 13 |
| Hematology/oncology | 11 |
| Registered Dietician/Nutrition Professional | 11 |
| Dermatology | 11 |
| Endocrinology | 11 |
| Critical care (intensivists) | 11 |
| Plastic and reconstructive surgery | 11 |
| Physical medicine and rehabilitation | 11 |
| Infectious disease | 10 |
| Otolaryngology | 10 |
| Interventional Cardiology | 10 |
| Independent Diagnostic Testing Facility (IDTF) | 9 |
| Clinical Laboratory (Billing Independently) | 8 |
| Ambulatory Surgical Center | 8 |
| Neurosurgery | 8 |
| Medical oncology | 7 |
| Occupational therapist (private practice) | 7 |
| Pharmacy | 7 |
| General practice | 5 |
| Portable X-Ray Supplier (Billing Independently) | 5 |
| Colorectal surgery (formerly proctology) | 4 |
| Audiologist (billing independently) | 4 |
| Thoracic surgery | 4 |
| Rheumatology | 4 |
| Cardiac Electrophysiology | 3 |
| Hospitalist | 3 |
| Certified clinical nurse specialist | 3 |
| Anesthesiologist Assistant | 3 |
| Radiation oncology | 3 |
| Vascular surgery | 3 |
| Interventional Pain Management (IPM) | 2 |
| Surgical oncology | 2 |
| Speech / language pathology | 2 |
| Sports Medicine | 2 |
| Undersea and Hyperbaric Medicine | 1 |
| Hospice and Palliative Care | 1 |
| Marriage and Family Therapist | 1 |
| Oral surgery (dentists only) | 1 |
| Pain Management | 1 |
| Cardiac surgery | 1 |
| Epileptologists | 1 |
| Hand surgery | 1 |
| Certified nurse midwife | 1 |
| Gynecologist/oncologist | 1 |
| Allergy/immunology | 1 |
| Interventional radiology | 1 |
| Advanced Heart Failure and Transplant Cardiology | 1 |
| Opioid Treatment Program | 1 |
| Public Health or Welfare Agencies (Federal, State, and local) | 1 |