| Nurse practitioner | 1,603 |
| Physical therapist (private practice) | 1,067 |
| Physician assistant | 923 |
| Family practice | 703 |
| Internal medicine | 617 |
| Certified Registered Nurse Anesthetist (CRNA) | 453 |
| Licensed clinical social worker | 428 |
| Clinical psychologist | 401 |
| Mental Health Counselors | 368 |
| Chiropractic | 340 |
| Optometrist | 284 |
| Anesthesiology | 257 |
| Obstetrics/gynecology | 253 |
| Psychiatry | 238 |
| Diagnostic Radiology | 232 |
| Emergency medicine | 226 |
| Mass Immunization Roster Billers | 207 |
| Occupational therapist (private practice) | 200 |
| Cardiology | 170 |
| Podiatry | 168 |
| Ophthalmology | 157 |
| Dermatology | 150 |
| General surgery | 145 |
| Orthopedic surgery | 138 |
| Hospitalist | 126 |
| Gastroenterology | 123 |
| Neurology | 117 |
| Audiologist (billing independently) | 101 |
| Physical medicine and rehabilitation | 94 |
| Hematology/oncology | 91 |
| Otolaryngology | 85 |
| Urology | 78 |
| Registered Dietician/Nutrition Professional | 77 |
| Pathology | 75 |
| Speech / language pathology | 73 |
| Pulmonary disease | 68 |
| Centralized Flu | 65 |
| Ambulance Service Supplier, e.g., private ambulance companies, funeral homes | 64 |
| Ambulatory Surgical Center | 54 |
| Radiation oncology | 54 |
| Rheumatology | 51 |
| Endocrinology | 49 |
| Nephrology | 45 |
| Plastic and reconstructive surgery | 42 |
| Neurosurgery | 41 |
| Marriage and Family Therapist | 36 |
| Infectious disease | 35 |
| Pharmacy | 34 |
| Allergy/immunology | 33 |
| Interventional Cardiology | 32 |
| Cardiac Electrophysiology | 31 |
| Pain Management | 25 |
| Vascular surgery | 24 |
| Oral surgery (dentists only) | 24 |
| Pediatric medicine | 24 |
| Hand surgery | 24 |
| Medical oncology | 23 |
| Thoracic surgery | 22 |
| Critical care (intensivists) | 22 |
| Sports Medicine | 20 |
| Maxillofacial surgery | 19 |
| Certified nurse midwife | 15 |
| General practice | 14 |
| Colorectal surgery (formerly proctology) | 13 |
| Gynecologist/oncologist | 11 |
| Geriatric medicine | 10 |
| Independent Diagnostic Testing Facility (IDTF) | 10 |
| Micrographic Dermatologic Surgery | 10 |
| Interventional radiology | 9 |
| Hematology | 8 |
| Cardiac surgery | 8 |
| Advanced Heart Failure and Transplant Cardiology | 8 |
| Hospice and Palliative Care | 8 |
| Opioid Treatment Program | 7 |
| Certified clinical nurse specialist | 7 |
| Clinical Laboratory (Billing Independently) | 7 |
| Osteopathic manipulative therapy | 6 |
| Hematopoietic Cell Transplantation and Cellular Therapy | 6 |
| Surgical oncology | 6 |
| Sleep Medicine | 6 |
| Psychologist (billing independently) | 4 |
| Interventional Pain Management (IPM) | 4 |
| Nuclear medicine | 3 |
| Medicare Diabetes Preventive Program | 3 |
| Neuropsychiatry | 2 |
| General Psychiatry | 2 |
| Dentist | 2 |
| Medical Genetics and Genomics | 2 |
| Addiction medicine | 1 |
| Undersea and Hyperbaric Medicine | 1 |
| Home Infusion Therapy Services | 1 |
| Portable X-Ray Supplier (Billing Independently) | 1 |