| Internal medicine | 9,018 |
| Nurse practitioner | 8,332 |
| Family practice | 7,393 |
| Physician assistant | 6,081 |
| Physical therapist (private practice) | 5,723 |
| Emergency medicine | 4,244 |
| Anesthesiology | 3,705 |
| Psychiatry | 2,454 |
| Diagnostic Radiology | 2,429 |
| Clinical psychologist | 2,327 |
| Obstetrics/gynecology | 2,269 |
| Optometrist | 2,263 |
| Licensed clinical social worker | 1,996 |
| Chiropractic | 1,961 |
| Marriage and Family Therapist | 1,829 |
| Ophthalmology | 1,584 |
| Hospitalist | 1,584 |
| Orthopedic surgery | 1,561 |
| Mass Immunization Roster Billers | 1,527 |
| General surgery | 1,508 |
| Certified Registered Nurse Anesthetist (CRNA) | 1,418 |
| Cardiology | 1,309 |
| Neurology | 1,297 |
| Dermatology | 1,226 |
| Podiatry | 1,127 |
| Gastroenterology | 1,028 |
| Pathology | 875 |
| Otolaryngology | 752 |
| Hematology/oncology | 733 |
| Urology | 722 |
| Nephrology | 687 |
| Occupational therapist (private practice) | 683 |
| Physical medicine and rehabilitation | 626 |
| Pulmonary disease | 607 |
| Pediatric medicine | 565 |
| Endocrinology | 479 |
| Ambulatory Surgical Center | 475 |
| Infectious disease | 473 |
| Critical care (intensivists) | 447 |
| Centralized Flu | 420 |
| General practice | 417 |
| Neurosurgery | 385 |
| Rheumatology | 375 |
| Plastic and reconstructive surgery | 356 |
| Radiation oncology | 355 |
| Interventional radiology | 313 |
| Audiologist (billing independently) | 308 |
| Vascular surgery | 300 |
| Speech / language pathology | 296 |
| Allergy/immunology | 290 |
| Registered Dietician/Nutrition Professional | 278 |
| Clinical Laboratory (Billing Independently) | 272 |
| Pharmacy | 228 |
| Interventional Cardiology | 215 |
| Pain Management | 207 |
| Hospice and Palliative Care | 197 |
| Medical oncology | 193 |
| Ambulance Service Supplier, e.g., private ambulance companies, funeral homes | 180 |
| Geriatric medicine | 176 |
| Thoracic surgery | 170 |
| Mental Health Counselors | 167 |
| Independent Diagnostic Testing Facility (IDTF) | 145 |
| Cardiac Electrophysiology | 137 |
| Certified nurse midwife | 115 |
| Colorectal surgery (formerly proctology) | 113 |
| Sports Medicine | 112 |
| Surgical oncology | 112 |
| Hand surgery | 106 |
| Psychologist (billing independently) | 104 |
| Cardiac surgery | 99 |
| Sleep Medicine | 85 |
| Hematology | 83 |
| Interventional Pain Management (IPM) | 80 |
| Gynecologist/oncologist | 77 |
| Nuclear medicine | 75 |
| Opioid Treatment Program | 70 |
| Osteopathic manipulative therapy | 68 |
| Oral surgery (dentists only) | 66 |
| Preventive medicine | 64 |
| Unknown physician specialty | 51 |
| Advanced Heart Failure and Transplant Cardiology | 51 |
| Addiction medicine | 35 |
| Dentist | 33 |
| Portable X-Ray Supplier (Billing Independently) | 32 |
| Micrographic Dermatologic Surgery | 28 |
| Maxillofacial surgery | 27 |
| Medical Genetics and Genomics | 21 |
| Neuropsychiatry | 21 |
| Epileptologists | 18 |
| General Psychiatry | 12 |
| Certified clinical nurse specialist | 12 |
| Unknown Provider | 11 |
| Hematopoietic Cell Transplantation and Cellular Therapy | 7 |
| Home Infusion Therapy Services | 6 |
| Adult Congenital Heart Disease | 5 |
| Medicare Diabetes Preventive Program | 4 |
| Undersea and Hyperbaric Medicine | 3 |
| Medical Toxicology | 3 |
| Slide Preparation Facilities | 2 |
| All other suppliers, e.g., Drug Stores | 2 |
| Intensive Cardiac Rehabilitation | 2 |
| Single or Multispecialty Clinic or Group Practice | 2 |
| Peripheral vascular disease | 2 |
| Orofacial Pain | 1 |