| Internal medicine | 13,947 |
| Nurse practitioner | 12,939 |
| Family practice | 11,410 |
| Physician assistant | 9,443 |
| Physical therapist (private practice) | 8,942 |
| Emergency medicine | 6,589 |
| Anesthesiology | 5,780 |
| Psychiatry | 3,792 |
| Diagnostic Radiology | 3,700 |
| Clinical psychologist | 3,595 |
| Optometrist | 3,562 |
| Obstetrics/gynecology | 3,503 |
| Licensed clinical social worker | 3,085 |
| Chiropractic | 3,004 |
| Marriage and Family Therapist | 2,839 |
| Ophthalmology | 2,463 |
| Hospitalist | 2,400 |
| Orthopedic surgery | 2,381 |
| Mass Immunization Roster Billers | 2,344 |
| General surgery | 2,283 |
| Certified Registered Nurse Anesthetist (CRNA) | 2,228 |
| Cardiology | 2,033 |
| Neurology | 2,017 |
| Dermatology | 1,847 |
| Podiatry | 1,761 |
| Gastroenterology | 1,612 |
| Pathology | 1,342 |
| Otolaryngology | 1,172 |
| Hematology/oncology | 1,165 |
| Urology | 1,129 |
| Nephrology | 1,076 |
| Occupational therapist (private practice) | 1,049 |
| Pulmonary disease | 1,020 |
| Physical medicine and rehabilitation | 954 |
| Pediatric medicine | 888 |
| Endocrinology | 736 |
| Infectious disease | 724 |
| Ambulatory Surgical Center | 712 |
| Critical care (intensivists) | 672 |
| Centralized Flu | 645 |
| General practice | 640 |
| Rheumatology | 610 |
| Neurosurgery | 575 |
| Plastic and reconstructive surgery | 559 |
| Radiation oncology | 558 |
| Audiologist (billing independently) | 489 |
| Interventional radiology | 465 |
| Vascular surgery | 451 |
| Speech / language pathology | 438 |
| Allergy/immunology | 435 |
| Registered Dietician/Nutrition Professional | 427 |
| Clinical Laboratory (Billing Independently) | 426 |
| Pharmacy | 347 |
| Interventional Cardiology | 333 |
| Pain Management | 333 |
| Medical oncology | 312 |
| Hospice and Palliative Care | 304 |
| Mental Health Counselors | 276 |
| Ambulance Service Supplier, e.g., private ambulance companies, funeral homes | 270 |
| Thoracic surgery | 265 |
| Geriatric medicine | 249 |
| Independent Diagnostic Testing Facility (IDTF) | 235 |
| Cardiac Electrophysiology | 212 |
| Certified nurse midwife | 186 |
| Surgical oncology | 173 |
| Colorectal surgery (formerly proctology) | 172 |
| Sports Medicine | 162 |
| Psychologist (billing independently) | 158 |
| Hand surgery | 146 |
| Cardiac surgery | 145 |
| Interventional Pain Management (IPM) | 129 |
| Opioid Treatment Program | 127 |
| Nuclear medicine | 122 |
| Sleep Medicine | 118 |
| Hematology | 117 |
| Osteopathic manipulative therapy | 112 |
| Gynecologist/oncologist | 108 |
| Oral surgery (dentists only) | 103 |
| Preventive medicine | 96 |
| Unknown physician specialty | 94 |
| Advanced Heart Failure and Transplant Cardiology | 70 |
| Dentist | 55 |
| Portable X-Ray Supplier (Billing Independently) | 49 |
| Addiction medicine | 44 |
| Maxillofacial surgery | 40 |
| Micrographic Dermatologic Surgery | 37 |
| Neuropsychiatry | 33 |
| Medical Genetics and Genomics | 32 |
| Epileptologists | 24 |
| General Psychiatry | 20 |
| Certified clinical nurse specialist | 16 |
| Unknown Provider | 16 |
| Home Infusion Therapy Services | 13 |
| Adult Congenital Heart Disease | 10 |
| Hematopoietic Cell Transplantation and Cellular Therapy | 7 |
| Undersea and Hyperbaric Medicine | 6 |
| Peripheral vascular disease | 6 |
| Medicare Diabetes Preventive Program | 5 |
| All other suppliers, e.g., Drug Stores | 4 |
| Slide Preparation Facilities | 3 |
| Medical Toxicology | 3 |
| Intensive Cardiac Rehabilitation | 3 |
| Single or Multispecialty Clinic or Group Practice | 3 |
| Orofacial Pain | 1 |
| Oral Medicine | 1 |