| Nurse practitioner | 3,077 |
| Physician assistant | 1,482 |
| Family practice | 1,103 |
| Certified Registered Nurse Anesthetist (CRNA) | 1,049 |
| Physical therapist (private practice) | 1,026 |
| Internal medicine | 889 |
| Emergency medicine | 623 |
| Anesthesiology | 468 |
| Chiropractic | 430 |
| Obstetrics/gynecology | 390 |
| Mass Immunization Roster Billers | 339 |
| Optometrist | 323 |
| Diagnostic Radiology | 319 |
| Licensed clinical social worker | 310 |
| Mental Health Counselors | 299 |
| General surgery | 277 |
| Psychiatry | 273 |
| Hospitalist | 267 |
| Orthopedic surgery | 264 |
| Occupational therapist (private practice) | 223 |
| Ophthalmology | 194 |
| Cardiology | 190 |
| Pediatric medicine | 157 |
| Neurology | 152 |
| Gastroenterology | 145 |
| Centralized Flu | 139 |
| Pulmonary disease | 130 |
| Otolaryngology | 127 |
| Dermatology | 126 |
| Podiatry | 118 |
| Clinical psychologist | 115 |
| Pathology | 112 |
| Urology | 109 |
| Hematology/oncology | 105 |
| Speech / language pathology | 101 |
| Audiologist (billing independently) | 96 |
| Nephrology | 91 |
| Physical medicine and rehabilitation | 84 |
| Ambulance Service Supplier, e.g., private ambulance companies, funeral homes | 74 |
| Rheumatology | 73 |
| Neurosurgery | 67 |
| Plastic and reconstructive surgery | 63 |
| Ambulatory Surgical Center | 60 |
| Infectious disease | 59 |
| Interventional Cardiology | 57 |
| Endocrinology | 57 |
| Vascular surgery | 56 |
| Radiation oncology | 55 |
| Anesthesiologist Assistant | 48 |
| Pharmacy | 44 |
| Critical care (intensivists) | 44 |
| Allergy/immunology | 40 |
| Independent Diagnostic Testing Facility (IDTF) | 34 |
| Cardiac Electrophysiology | 34 |
| Marriage and Family Therapist | 30 |
| Registered Dietician/Nutrition Professional | 30 |
| Clinical Laboratory (Billing Independently) | 30 |
| Thoracic surgery | 28 |
| Sports Medicine | 28 |
| Certified nurse midwife | 26 |
| Hand surgery | 25 |
| Interventional radiology | 24 |
| General practice | 22 |
| Colorectal surgery (formerly proctology) | 21 |
| Hospice and Palliative Care | 20 |
| Pain Management | 19 |
| Medical oncology | 17 |
| Opioid Treatment Program | 16 |
| Gynecologist/oncologist | 15 |
| Cardiac surgery | 15 |
| Interventional Pain Management (IPM) | 14 |
| Surgical oncology | 12 |
| Geriatric medicine | 12 |
| Sleep Medicine | 8 |
| Maxillofacial surgery | 8 |
| Advanced Heart Failure and Transplant Cardiology | 8 |
| Neuropsychiatry | 7 |
| Hematology | 7 |
| Medical Genetics and Genomics | 7 |
| Oral surgery (dentists only) | 6 |
| Osteopathic manipulative therapy | 5 |
| Micrographic Dermatologic Surgery | 5 |
| General Psychiatry | 4 |
| Dentist | 4 |
| Certified clinical nurse specialist | 4 |
| Addiction medicine | 3 |
| Hematopoietic Cell Transplantation and Cellular Therapy | 3 |
| Unknown Provider | 3 |
| Public Health or Welfare Agencies (Federal, State, and local) | 3 |
| Preventive medicine | 3 |
| Medicare Diabetes Preventive Program | 2 |
| Psychologist (billing independently) | 2 |
| Nuclear medicine | 2 |
| Home Infusion Therapy Services | 2 |
| Medical Toxicology | 2 |
| Oral and Maxillofacial Pathology | 1 |
| Undersea and Hyperbaric Medicine | 1 |
| Mammography Screening Center | 1 |
| Orofacial Pain | 1 |
| Single or Multispecialty Clinic or Group Practice | 1 |