| Nurse practitioner | 1,212 |
| Physical therapist (private practice) | 997 |
| Internal medicine | 713 |
| Physician assistant | 591 |
| Licensed clinical social worker | 543 |
| Chiropractic | 359 |
| Occupational therapist (private practice) | 319 |
| Anesthesiology | 302 |
| Family practice | 301 |
| Emergency medicine | 208 |
| Obstetrics/gynecology | 206 |
| Clinical psychologist | 196 |
| Diagnostic Radiology | 193 |
| Optometrist | 192 |
| Podiatry | 184 |
| Mental Health Counselors | 171 |
| Cardiology | 169 |
| Certified Registered Nurse Anesthetist (CRNA) | 157 |
| Psychiatry | 154 |
| Mass Immunization Roster Billers | 143 |
| Orthopedic surgery | 121 |
| Neurology | 117 |
| General surgery | 115 |
| Ophthalmology | 106 |
| Gastroenterology | 101 |
| Physical medicine and rehabilitation | 88 |
| Pulmonary disease | 79 |
| Speech / language pathology | 74 |
| Otolaryngology | 74 |
| Dermatology | 67 |
| Urology | 61 |
| Nephrology | 60 |
| Pathology | 57 |
| Endocrinology | 57 |
| Hematology/oncology | 56 |
| Centralized Flu | 56 |
| Pediatric medicine | 52 |
| Ambulance Service Supplier, e.g., private ambulance companies, funeral homes | 49 |
| Infectious disease | 46 |
| Ambulatory Surgical Center | 45 |
| Registered Dietician/Nutrition Professional | 44 |
| Audiologist (billing independently) | 39 |
| Vascular surgery | 36 |
| Plastic and reconstructive surgery | 33 |
| Pharmacy | 33 |
| Radiation oncology | 32 |
| Medical oncology | 31 |
| Hospitalist | 29 |
| Rheumatology | 28 |
| Neurosurgery | 27 |
| Pain Management | 26 |
| Interventional Cardiology | 25 |
| Allergy/immunology | 24 |
| Marriage and Family Therapist | 23 |
| Interventional radiology | 22 |
| Geriatric medicine | 21 |
| Thoracic surgery | 19 |
| Certified nurse midwife | 19 |
| Independent Diagnostic Testing Facility (IDTF) | 18 |
| Clinical Laboratory (Billing Independently) | 17 |
| Surgical oncology | 15 |
| Critical care (intensivists) | 15 |
| Colorectal surgery (formerly proctology) | 14 |
| Cardiac Electrophysiology | 14 |
| Sports Medicine | 13 |
| Interventional Pain Management (IPM) | 13 |
| Oral surgery (dentists only) | 13 |
| Hand surgery | 12 |
| Gynecologist/oncologist | 10 |
| General practice | 9 |
| Hospice and Palliative Care | 7 |
| Certified clinical nurse specialist | 7 |
| Cardiac surgery | 6 |
| Opioid Treatment Program | 6 |
| Osteopathic manipulative therapy | 5 |
| Micrographic Dermatologic Surgery | 4 |
| Preventive medicine | 4 |
| Hematology | 4 |
| Home Infusion Therapy Services | 4 |
| Addiction medicine | 3 |
| Portable X-Ray Supplier (Billing Independently) | 3 |
| Sleep Medicine | 3 |
| Nuclear medicine | 3 |
| General Psychiatry | 3 |
| Single or Multispecialty Clinic or Group Practice | 3 |
| Dentist | 2 |
| Public Health or Welfare Agencies (Federal, State, and local) | 1 |
| Hematopoietic Cell Transplantation and Cellular Therapy | 1 |
| Advanced Heart Failure and Transplant Cardiology | 1 |
| Psychologist (billing independently) | 1 |
| Epileptologists | 1 |
| Medical Genetics and Genomics | 1 |
| Oral Medicine | 1 |