| Nurse practitioner | 4,562 |
| Physician assistant | 1,379 |
| Family practice | 1,355 |
| Internal medicine | 1,048 |
| Physical therapist (private practice) | 1,043 |
| Licensed clinical social worker | 814 |
| Emergency medicine | 762 |
| Anesthesiology | 732 |
| Optometrist | 677 |
| Chiropractic | 451 |
| Obstetrics/gynecology | 439 |
| Diagnostic Radiology | 421 |
| Certified Registered Nurse Anesthetist (CRNA) | 416 |
| Mass Immunization Roster Billers | 373 |
| Mental Health Counselors | 329 |
| General surgery | 317 |
| Orthopedic surgery | 300 |
| Occupational therapist (private practice) | 286 |
| Hospitalist | 280 |
| Cardiology | 273 |
| Clinical psychologist | 250 |
| Psychiatry | 233 |
| Neurology | 204 |
| Podiatry | 195 |
| Gastroenterology | 183 |
| Pulmonary disease | 181 |
| Ophthalmology | 169 |
| Audiologist (billing independently) | 153 |
| Ambulance Service Supplier, e.g., private ambulance companies, funeral homes | 145 |
| Pathology | 136 |
| Urology | 133 |
| Hematology/oncology | 127 |
| Pediatric medicine | 119 |
| Nephrology | 119 |
| Otolaryngology | 118 |
| Dermatology | 112 |
| Centralized Flu | 111 |
| Speech / language pathology | 104 |
| Ambulatory Surgical Center | 96 |
| Interventional Cardiology | 87 |
| Endocrinology | 86 |
| Infectious disease | 85 |
| Anesthesiologist Assistant | 84 |
| Physical medicine and rehabilitation | 78 |
| Pharmacy | 78 |
| Critical care (intensivists) | 70 |
| Radiation oncology | 70 |
| Registered Dietician/Nutrition Professional | 60 |
| Certified nurse midwife | 60 |
| Rheumatology | 56 |
| Marriage and Family Therapist | 54 |
| Neurosurgery | 53 |
| Pain Management | 49 |
| Thoracic surgery | 45 |
| Plastic and reconstructive surgery | 45 |
| Cardiac Electrophysiology | 42 |
| Certified clinical nurse specialist | 39 |
| Medical oncology | 39 |
| Interventional radiology | 37 |
| Allergy/immunology | 36 |
| Sports Medicine | 36 |
| Vascular surgery | 33 |
| Hospice and Palliative Care | 30 |
| Colorectal surgery (formerly proctology) | 24 |
| Geriatric medicine | 23 |
| General practice | 23 |
| Independent Diagnostic Testing Facility (IDTF) | 22 |
| Hand surgery | 22 |
| Maxillofacial surgery | 20 |
| Clinical Laboratory (Billing Independently) | 19 |
| Interventional Pain Management (IPM) | 18 |
| Oral surgery (dentists only) | 18 |
| Sleep Medicine | 17 |
| Gynecologist/oncologist | 15 |
| Opioid Treatment Program | 12 |
| Single or Multispecialty Clinic or Group Practice | 12 |
| Osteopathic manipulative therapy | 11 |
| Surgical oncology | 10 |
| Cardiac surgery | 9 |
| Advanced Heart Failure and Transplant Cardiology | 8 |
| Preventive medicine | 7 |
| Addiction medicine | 5 |
| Hematology | 4 |
| Medical Genetics and Genomics | 4 |
| Nuclear medicine | 3 |
| Micrographic Dermatologic Surgery | 3 |
| Psychologist (billing independently) | 2 |
| Neuropsychiatry | 2 |
| Home Infusion Therapy Services | 2 |
| Portable X-Ray Supplier (Billing Independently) | 2 |
| Mammography Screening Center | 1 |
| Unknown physician specialty | 1 |
| Medicare Diabetes Preventive Program | 1 |
| Hematopoietic Cell Transplantation and Cellular Therapy | 1 |
| General Psychiatry | 1 |
| Dentist | 1 |
| Radiation Therapy Centers | 1 |