| Internal medicine | 3,631 |
| Nurse practitioner | 3,263 |
| Family practice | 2,624 |
| Physical therapist (private practice) | 2,122 |
| Physician assistant | 2,055 |
| Anesthesiology | 1,553 |
| Emergency medicine | 1,458 |
| Diagnostic Radiology | 973 |
| Psychiatry | 915 |
| Clinical psychologist | 890 |
| Optometrist | 826 |
| Obstetrics/gynecology | 796 |
| Licensed clinical social worker | 776 |
| Ophthalmology | 684 |
| Mass Immunization Roster Billers | 619 |
| Hospitalist | 609 |
| Marriage and Family Therapist | 591 |
| Orthopedic surgery | 584 |
| Chiropractic | 568 |
| Neurology | 552 |
| General surgery | 549 |
| Cardiology | 547 |
| Podiatry | 516 |
| Certified Registered Nurse Anesthetist (CRNA) | 491 |
| Dermatology | 470 |
| Gastroenterology | 434 |
| Pathology | 381 |
| Urology | 323 |
| Hematology/oncology | 313 |
| Pulmonary disease | 307 |
| Nephrology | 307 |
| Otolaryngology | 306 |
| General practice | 282 |
| Occupational therapist (private practice) | 268 |
| Physical medicine and rehabilitation | 264 |
| Clinical Laboratory (Billing Independently) | 234 |
| Infectious disease | 225 |
| Pediatric medicine | 218 |
| Endocrinology | 212 |
| Ambulatory Surgical Center | 204 |
| Rheumatology | 183 |
| Plastic and reconstructive surgery | 155 |
| Neurosurgery | 153 |
| Interventional radiology | 150 |
| Radiation oncology | 144 |
| Speech / language pathology | 137 |
| Vascular surgery | 124 |
| Critical care (intensivists) | 122 |
| Independent Diagnostic Testing Facility (IDTF) | 122 |
| Audiologist (billing independently) | 121 |
| Centralized Flu | 119 |
| Pharmacy | 117 |
| Hospice and Palliative Care | 115 |
| Allergy/immunology | 106 |
| Medical oncology | 99 |
| Pain Management | 84 |
| Interventional Cardiology | 82 |
| Thoracic surgery | 81 |
| Registered Dietician/Nutrition Professional | 74 |
| Geriatric medicine | 74 |
| Surgical oncology | 68 |
| Cardiac Electrophysiology | 65 |
| Ambulance Service Supplier, e.g., private ambulance companies, funeral homes | 57 |
| Colorectal surgery (formerly proctology) | 57 |
| Hematology | 55 |
| Mental Health Counselors | 53 |
| Sports Medicine | 49 |
| Psychologist (billing independently) | 43 |
| Hand surgery | 40 |
| Cardiac surgery | 37 |
| Oral surgery (dentists only) | 36 |
| Nuclear medicine | 36 |
| Opioid Treatment Program | 34 |
| Portable X-Ray Supplier (Billing Independently) | 28 |
| Interventional Pain Management (IPM) | 27 |
| Gynecologist/oncologist | 26 |
| Advanced Heart Failure and Transplant Cardiology | 26 |
| Unknown physician specialty | 23 |
| Osteopathic manipulative therapy | 22 |
| Certified nurse midwife | 21 |
| Dentist | 18 |
| Preventive medicine | 16 |
| Sleep Medicine | 13 |
| Maxillofacial surgery | 13 |
| General Psychiatry | 12 |
| Medical Genetics and Genomics | 11 |
| Neuropsychiatry | 8 |
| Epileptologists | 6 |
| Addiction medicine | 6 |
| Home Infusion Therapy Services | 6 |
| Micrographic Dermatologic Surgery | 5 |
| Unknown Provider | 4 |
| Peripheral vascular disease | 3 |
| Medicare Diabetes Preventive Program | 2 |
| All other suppliers, e.g., Drug Stores | 2 |
| Adult Congenital Heart Disease | 2 |
| Intensive Cardiac Rehabilitation | 1 |
| Hematopoietic Cell Transplantation and Cellular Therapy | 1 |
| Orofacial Pain | 1 |
| Certified clinical nurse specialist | 1 |
| Undersea and Hyperbaric Medicine | 1 |