| Nurse practitioner | 2,614 |
| Physician assistant | 2,371 |
| Physical therapist (private practice) | 1,588 |
| Family practice | 1,314 |
| Internal medicine | 890 |
| Mental Health Counselors | 836 |
| Licensed clinical social worker | 834 |
| Emergency medicine | 677 |
| Anesthesiology | 594 |
| Optometrist | 520 |
| Certified Registered Nurse Anesthetist (CRNA) | 509 |
| Chiropractic | 431 |
| Clinical psychologist | 368 |
| Obstetrics/gynecology | 368 |
| Diagnostic Radiology | 328 |
| Hospitalist | 324 |
| Orthopedic surgery | 311 |
| General surgery | 294 |
| Psychiatry | 258 |
| Mass Immunization Roster Billers | 250 |
| Occupational therapist (private practice) | 237 |
| Neurology | 197 |
| Ophthalmology | 191 |
| Dermatology | 185 |
| Gastroenterology | 179 |
| Cardiology | 158 |
| Pulmonary disease | 139 |
| Physical medicine and rehabilitation | 133 |
| Podiatry | 132 |
| Anesthesiologist Assistant | 131 |
| Audiologist (billing independently) | 129 |
| Otolaryngology | 122 |
| Urology | 121 |
| Speech / language pathology | 119 |
| Pathology | 116 |
| Ambulance Service Supplier, e.g., private ambulance companies, funeral homes | 116 |
| Hematology/oncology | 98 |
| Centralized Flu | 96 |
| Marriage and Family Therapist | 90 |
| Certified nurse midwife | 90 |
| Nephrology | 88 |
| Infectious disease | 82 |
| Ambulatory Surgical Center | 74 |
| Endocrinology | 72 |
| Critical care (intensivists) | 68 |
| Neurosurgery | 68 |
| Interventional Cardiology | 66 |
| Rheumatology | 62 |
| Radiation oncology | 59 |
| Registered Dietician/Nutrition Professional | 59 |
| Medical oncology | 49 |
| Allergy/immunology | 47 |
| Plastic and reconstructive surgery | 47 |
| Interventional radiology | 43 |
| Pediatric medicine | 41 |
| Thoracic surgery | 38 |
| Vascular surgery | 36 |
| Clinical Laboratory (Billing Independently) | 34 |
| Cardiac Electrophysiology | 34 |
| Certified clinical nurse specialist | 32 |
| Independent Diagnostic Testing Facility (IDTF) | 32 |
| Sports Medicine | 31 |
| General practice | 31 |
| Hand surgery | 29 |
| Geriatric medicine | 29 |
| Hospice and Palliative Care | 25 |
| Pharmacy | 25 |
| Pain Management | 24 |
| Sleep Medicine | 17 |
| Oral surgery (dentists only) | 16 |
| Osteopathic manipulative therapy | 16 |
| Opioid Treatment Program | 15 |
| Surgical oncology | 15 |
| Gynecologist/oncologist | 14 |
| Colorectal surgery (formerly proctology) | 11 |
| Micrographic Dermatologic Surgery | 11 |
| Advanced Heart Failure and Transplant Cardiology | 9 |
| Hematopoietic Cell Transplantation and Cellular Therapy | 8 |
| Cardiac surgery | 7 |
| Medical Genetics and Genomics | 7 |
| Hematology | 7 |
| Medical Toxicology | 7 |
| Epileptologists | 6 |
| Maxillofacial surgery | 4 |
| Interventional Pain Management (IPM) | 4 |
| Neuropsychiatry | 4 |
| Addiction medicine | 4 |
| Preventive medicine | 3 |
| Nuclear medicine | 3 |
| Dentist | 3 |
| Single or Multispecialty Clinic or Group Practice | 3 |
| Portable X-Ray Supplier (Billing Independently) | 2 |
| Public Health or Welfare Agencies (Federal, State, and local) | 1 |
| Unknown Provider | 1 |
| Psychologist (billing independently) | 1 |
| Adult Congenital Heart Disease | 1 |
| General Psychiatry | 1 |
| Home Infusion Therapy Services | 1 |