| Nurse practitioner | 14,036 |
| Physician assistant | 11,475 |
| Internal medicine | 8,150 |
| Physical therapist (private practice) | 7,890 |
| Licensed clinical social worker | 5,562 |
| Family practice | 4,078 |
| Anesthesiology | 3,783 |
| Emergency medicine | 3,417 |
| Psychiatry | 2,827 |
| Diagnostic Radiology | 2,727 |
| Obstetrics/gynecology | 2,532 |
| Clinical psychologist | 2,274 |
| Certified Registered Nurse Anesthetist (CRNA) | 2,161 |
| Cardiology | 2,024 |
| Chiropractic | 1,748 |
| Hospitalist | 1,727 |
| Mass Immunization Roster Billers | 1,645 |
| Optometrist | 1,619 |
| Neurology | 1,580 |
| Podiatry | 1,563 |
| Occupational therapist (private practice) | 1,543 |
| General surgery | 1,475 |
| Ophthalmology | 1,472 |
| Gastroenterology | 1,405 |
| Orthopedic surgery | 1,404 |
| Mental Health Counselors | 1,332 |
| Pathology | 1,146 |
| Dermatology | 1,025 |
| Physical medicine and rehabilitation | 890 |
| Pulmonary disease | 843 |
| Urology | 822 |
| Otolaryngology | 749 |
| Nephrology | 725 |
| Endocrinology | 700 |
| Pediatric medicine | 696 |
| Hematology/oncology | 664 |
| Ambulance Service Supplier, e.g., private ambulance companies, funeral homes | 654 |
| Audiologist (billing independently) | 632 |
| Infectious disease | 602 |
| Speech / language pathology | 556 |
| Medical oncology | 529 |
| Centralized Flu | 460 |
| Critical care (intensivists) | 444 |
| Registered Dietician/Nutrition Professional | 422 |
| Rheumatology | 416 |
| Plastic and reconstructive surgery | 393 |
| Neurosurgery | 390 |
| Radiation oncology | 355 |
| Certified nurse midwife | 349 |
| Vascular surgery | 318 |
| Allergy/immunology | 291 |
| Pharmacy | 265 |
| Pain Management | 230 |
| Interventional Cardiology | 228 |
| Interventional radiology | 219 |
| Thoracic surgery | 212 |
| Geriatric medicine | 206 |
| General practice | 186 |
| Cardiac Electrophysiology | 176 |
| Hospice and Palliative Care | 176 |
| Colorectal surgery (formerly proctology) | 176 |
| Ambulatory Surgical Center | 173 |
| Sports Medicine | 122 |
| Oral surgery (dentists only) | 118 |
| Clinical Laboratory (Billing Independently) | 112 |
| Surgical oncology | 110 |
| Hematology | 108 |
| Hand surgery | 104 |
| Gynecologist/oncologist | 101 |
| Cardiac surgery | 92 |
| Nuclear medicine | 85 |
| Marriage and Family Therapist | 81 |
| Advanced Heart Failure and Transplant Cardiology | 77 |
| Independent Diagnostic Testing Facility (IDTF) | 74 |
| Interventional Pain Management (IPM) | 64 |
| Opioid Treatment Program | 59 |
| Osteopathic manipulative therapy | 58 |
| Maxillofacial surgery | 43 |
| Sleep Medicine | 42 |
| Dentist | 31 |
| Neuropsychiatry | 25 |
| Addiction medicine | 25 |
| Micrographic Dermatologic Surgery | 23 |
| Preventive medicine | 23 |
| Medical Genetics and Genomics | 22 |
| Hematopoietic Cell Transplantation and Cellular Therapy | 21 |
| Portable X-Ray Supplier (Billing Independently) | 18 |
| Single or Multispecialty Clinic or Group Practice | 18 |
| Certified clinical nurse specialist | 18 |
| General Psychiatry | 12 |
| Medical Toxicology | 11 |
| Undersea and Hyperbaric Medicine | 11 |
| Unknown physician specialty | 10 |
| Epileptologists | 9 |
| Home Infusion Therapy Services | 8 |
| Adult Congenital Heart Disease | 8 |
| Oral and Maxillofacial Pathology | 4 |
| Medicare Diabetes Preventive Program | 4 |
| Psychologist (billing independently) | 4 |
| All other suppliers, e.g., Drug Stores | 3 |
| Anesthesiologist Assistant | 2 |
| Intensive Cardiac Rehabilitation | 2 |
| Radiation Therapy Centers | 2 |
| Unknown Provider | 1 |
| Oral Medicine | 1 |
| Peripheral vascular disease | 1 |
| Prosthodontics | 1 |