| Nurse practitioner | 805 |
| Internal medicine | 518 |
| Physician assistant | 490 |
| Family practice | 343 |
| Certified Registered Nurse Anesthetist (CRNA) | 323 |
| Licensed clinical social worker | 287 |
| Physical therapist (private practice) | 270 |
| Emergency medicine | 258 |
| Anesthesiology | 166 |
| Obstetrics/gynecology | 151 |
| Diagnostic Radiology | 146 |
| Psychiatry | 126 |
| Chiropractic | 116 |
| Cardiology | 102 |
| Podiatry | 99 |
| Clinical psychologist | 95 |
| General surgery | 93 |
| Mass Immunization Roster Billers | 91 |
| Mental Health Counselors | 88 |
| Neurology | 87 |
| Ophthalmology | 85 |
| Pediatric medicine | 83 |
| Pathology | 80 |
| Orthopedic surgery | 69 |
| Gastroenterology | 67 |
| Optometrist | 67 |
| Pulmonary disease | 60 |
| Infectious disease | 52 |
| Nephrology | 52 |
| Physical medicine and rehabilitation | 48 |
| Dermatology | 46 |
| Occupational therapist (private practice) | 43 |
| Hospitalist | 34 |
| Otolaryngology | 32 |
| Hematology/oncology | 30 |
| Endocrinology | 26 |
| Certified nurse midwife | 23 |
| Audiologist (billing independently) | 22 |
| Urology | 22 |
| Centralized Flu | 22 |
| Ambulance Service Supplier, e.g., private ambulance companies, funeral homes | 21 |
| Medical oncology | 21 |
| Thoracic surgery | 20 |
| Rheumatology | 19 |
| Neurosurgery | 19 |
| Radiation oncology | 18 |
| Interventional Cardiology | 18 |
| Critical care (intensivists) | 18 |
| Pharmacy | 18 |
| Clinical Laboratory (Billing Independently) | 17 |
| Vascular surgery | 16 |
| General practice | 16 |
| Colorectal surgery (formerly proctology) | 14 |
| Interventional radiology | 13 |
| Speech / language pathology | 13 |
| Allergy/immunology | 12 |
| Plastic and reconstructive surgery | 12 |
| Pain Management | 11 |
| Hospice and Palliative Care | 10 |
| Opioid Treatment Program | 8 |
| Advanced Heart Failure and Transplant Cardiology | 8 |
| Ambulatory Surgical Center | 8 |
| Geriatric medicine | 7 |
| Hematology | 6 |
| Independent Diagnostic Testing Facility (IDTF) | 6 |
| Sports Medicine | 5 |
| Hand surgery | 5 |
| Oral surgery (dentists only) | 4 |
| Nuclear medicine | 4 |
| Maxillofacial surgery | 4 |
| Epileptologists | 4 |
| Addiction medicine | 3 |
| Cardiac Electrophysiology | 3 |
| Registered Dietician/Nutrition Professional | 2 |
| Gynecologist/oncologist | 2 |
| Medical Genetics and Genomics | 2 |
| Osteopathic manipulative therapy | 2 |
| Marriage and Family Therapist | 2 |
| Dentist | 1 |
| Preventive medicine | 1 |
| General Psychiatry | 1 |
| Adult Congenital Heart Disease | 1 |
| Interventional Pain Management (IPM) | 1 |
| Surgical oncology | 1 |
| Neuropsychiatry | 1 |
| Certified clinical nurse specialist | 1 |
| Cardiac surgery | 1 |
| Hematopoietic Cell Transplantation and Cellular Therapy | 1 |