| Nurse practitioner | 18,511 |
| Physician assistant | 7,689 |
| Family practice | 7,231 |
| Internal medicine | 7,053 |
| Certified Registered Nurse Anesthetist (CRNA) | 4,614 |
| Physical therapist (private practice) | 4,567 |
| Emergency medicine | 4,083 |
| Anesthesiology | 3,651 |
| Optometrist | 2,916 |
| Obstetrics/gynecology | 2,434 |
| Diagnostic Radiology | 2,370 |
| Mental Health Counselors | 2,356 |
| Mass Immunization Roster Billers | 2,176 |
| Chiropractic | 1,903 |
| Licensed clinical social worker | 1,837 |
| Orthopedic surgery | 1,665 |
| General surgery | 1,648 |
| Psychiatry | 1,539 |
| Cardiology | 1,421 |
| Ophthalmology | 1,263 |
| Neurology | 1,208 |
| Clinical psychologist | 1,185 |
| Gastroenterology | 1,159 |
| Hospitalist | 1,096 |
| Pathology | 1,082 |
| Dermatology | 1,037 |
| Podiatry | 1,021 |
| Pediatric medicine | 928 |
| Nephrology | 906 |
| Pulmonary disease | 714 |
| Otolaryngology | 703 |
| Centralized Flu | 691 |
| Urology | 688 |
| Physical medicine and rehabilitation | 646 |
| Hematology/oncology | 646 |
| Ambulance Service Supplier, e.g., private ambulance companies, funeral homes | 641 |
| Occupational therapist (private practice) | 635 |
| Audiologist (billing independently) | 563 |
| Endocrinology | 513 |
| Interventional Cardiology | 502 |
| Ambulatory Surgical Center | 467 |
| Infectious disease | 457 |
| Neurosurgery | 448 |
| Registered Dietician/Nutrition Professional | 412 |
| Anesthesiologist Assistant | 403 |
| Rheumatology | 402 |
| Medical oncology | 392 |
| Plastic and reconstructive surgery | 387 |
| Speech / language pathology | 383 |
| Critical care (intensivists) | 362 |
| Radiation oncology | 348 |
| Pharmacy | 302 |
| Allergy/immunology | 292 |
| Vascular surgery | 279 |
| Independent Diagnostic Testing Facility (IDTF) | 274 |
| Pain Management | 271 |
| Thoracic surgery | 239 |
| Clinical Laboratory (Billing Independently) | 233 |
| General practice | 229 |
| Cardiac Electrophysiology | 192 |
| Certified clinical nurse specialist | 181 |
| Colorectal surgery (formerly proctology) | 180 |
| Interventional radiology | 176 |
| Interventional Pain Management (IPM) | 169 |
| Marriage and Family Therapist | 167 |
| Hospice and Palliative Care | 151 |
| Surgical oncology | 137 |
| Geriatric medicine | 123 |
| Sports Medicine | 113 |
| Certified nurse midwife | 113 |
| Hand surgery | 107 |
| Gynecologist/oncologist | 87 |
| Oral surgery (dentists only) | 70 |
| Cardiac surgery | 64 |
| Opioid Treatment Program | 54 |
| Maxillofacial surgery | 54 |
| Advanced Heart Failure and Transplant Cardiology | 48 |
| Hematology | 48 |
| Portable X-Ray Supplier (Billing Independently) | 41 |
| Sleep Medicine | 35 |
| Micrographic Dermatologic Surgery | 34 |
| Preventive medicine | 34 |
| Dentist | 33 |
| Nuclear medicine | 32 |
| Osteopathic manipulative therapy | 24 |
| Hematopoietic Cell Transplantation and Cellular Therapy | 21 |
| Medical Genetics and Genomics | 21 |
| Single or Multispecialty Clinic or Group Practice | 15 |
| Psychologist (billing independently) | 14 |
| Undersea and Hyperbaric Medicine | 12 |
| Addiction medicine | 12 |
| Epileptologists | 12 |
| Home Infusion Therapy Services | 10 |
| General Psychiatry | 7 |
| Oral and Maxillofacial Pathology | 6 |
| Neuropsychiatry | 5 |
| Medicare Diabetes Preventive Program | 3 |
| Public Health or Welfare Agencies (Federal, State, and local) | 3 |
| Unknown Provider | 2 |
| Peripheral vascular disease | 1 |
| Orofacial Pain | 1 |
| Adult Congenital Heart Disease | 1 |