| Nurse practitioner | 4,301 |
| Physical therapist (private practice) | 3,103 |
| Internal medicine | 2,443 |
| Physician assistant | 2,122 |
| Licensed clinical social worker | 1,488 |
| Family practice | 1,225 |
| Anesthesiology | 1,074 |
| Chiropractic | 1,062 |
| Emergency medicine | 904 |
| Occupational therapist (private practice) | 801 |
| Obstetrics/gynecology | 782 |
| Certified Registered Nurse Anesthetist (CRNA) | 678 |
| Diagnostic Radiology | 673 |
| Optometrist | 634 |
| Clinical psychologist | 632 |
| Cardiology | 615 |
| Podiatry | 614 |
| Psychiatry | 585 |
| Mass Immunization Roster Billers | 529 |
| Mental Health Counselors | 487 |
| Orthopedic surgery | 456 |
| General surgery | 400 |
| Ophthalmology | 391 |
| Gastroenterology | 386 |
| Neurology | 378 |
| Physical medicine and rehabilitation | 301 |
| Pulmonary disease | 257 |
| Dermatology | 240 |
| Urology | 222 |
| Nephrology | 221 |
| Hematology/oncology | 219 |
| Hospitalist | 205 |
| Pathology | 201 |
| Otolaryngology | 199 |
| Endocrinology | 199 |
| Pediatric medicine | 197 |
| Speech / language pathology | 195 |
| Ambulance Service Supplier, e.g., private ambulance companies, funeral homes | 184 |
| Centralized Flu | 181 |
| Infectious disease | 170 |
| Registered Dietician/Nutrition Professional | 144 |
| Ambulatory Surgical Center | 140 |
| Audiologist (billing independently) | 134 |
| Rheumatology | 130 |
| Plastic and reconstructive surgery | 115 |
| Critical care (intensivists) | 108 |
| Vascular surgery | 107 |
| Neurosurgery | 104 |
| Allergy/immunology | 101 |
| Pharmacy | 92 |
| Radiation oncology | 91 |
| Interventional Cardiology | 90 |
| Certified nurse midwife | 88 |
| Pain Management | 77 |
| Medical oncology | 75 |
| Marriage and Family Therapist | 71 |
| Interventional radiology | 60 |
| Thoracic surgery | 58 |
| Cardiac Electrophysiology | 55 |
| Geriatric medicine | 52 |
| Colorectal surgery (formerly proctology) | 47 |
| Clinical Laboratory (Billing Independently) | 47 |
| Sports Medicine | 47 |
| Oral surgery (dentists only) | 46 |
| Independent Diagnostic Testing Facility (IDTF) | 38 |
| Surgical oncology | 38 |
| Hand surgery | 37 |
| General practice | 32 |
| Gynecologist/oncologist | 28 |
| Interventional Pain Management (IPM) | 27 |
| Certified clinical nurse specialist | 26 |
| Opioid Treatment Program | 23 |
| Cardiac surgery | 23 |
| Hospice and Palliative Care | 21 |
| Nuclear medicine | 17 |
| Addiction medicine | 16 |
| Osteopathic manipulative therapy | 14 |
| Hematology | 13 |
| Dentist | 12 |
| Advanced Heart Failure and Transplant Cardiology | 11 |
| Sleep Medicine | 11 |
| Maxillofacial surgery | 11 |
| General Psychiatry | 8 |
| Micrographic Dermatologic Surgery | 7 |
| Preventive medicine | 7 |
| Single or Multispecialty Clinic or Group Practice | 7 |
| Home Infusion Therapy Services | 5 |
| Psychologist (billing independently) | 5 |
| Portable X-Ray Supplier (Billing Independently) | 3 |
| Hematopoietic Cell Transplantation and Cellular Therapy | 2 |
| Neuropsychiatry | 2 |
| Epileptologists | 2 |
| Public Health or Welfare Agencies (Federal, State, and local) | 1 |
| Unknown Provider | 1 |
| Medicare Diabetes Preventive Program | 1 |
| Medical Genetics and Genomics | 1 |
| Oral Medicine | 1 |