| Physician assistant | 201 |
| Nurse practitioner | 191 |
| Internal medicine | 187 |
| Licensed clinical social worker | 148 |
| Family practice | 115 |
| Certified Registered Nurse Anesthetist (CRNA) | 114 |
| Physical therapist (private practice) | 93 |
| Emergency medicine | 69 |
| Anesthesiology | 61 |
| Diagnostic Radiology | 54 |
| Clinical psychologist | 51 |
| Psychiatry | 43 |
| Obstetrics/gynecology | 43 |
| Ophthalmology | 41 |
| Chiropractic | 40 |
| Neurology | 31 |
| Gastroenterology | 28 |
| Cardiology | 27 |
| Optometrist | 25 |
| Dermatology | 25 |
| Pathology | 25 |
| Mass Immunization Roster Billers | 24 |
| General surgery | 24 |
| Mental Health Counselors | 23 |
| Orthopedic surgery | 22 |
| Hospitalist | 21 |
| Urology | 20 |
| Occupational therapist (private practice) | 20 |
| Endocrinology | 20 |
| Physical medicine and rehabilitation | 17 |
| Podiatry | 14 |
| Allergy/immunology | 13 |
| Pulmonary disease | 12 |
| Geriatric medicine | 12 |
| Pediatric medicine | 11 |
| Otolaryngology | 11 |
| Audiologist (billing independently) | 10 |
| Nephrology | 10 |
| Cardiac Electrophysiology | 9 |
| Rheumatology | 9 |
| Hospice and Palliative Care | 8 |
| Speech / language pathology | 8 |
| Hematology/oncology | 8 |
| Infectious disease | 7 |
| Interventional radiology | 6 |
| Radiation oncology | 6 |
| Certified nurse midwife | 6 |
| Thoracic surgery | 5 |
| Plastic and reconstructive surgery | 5 |
| Sports Medicine | 5 |
| Sleep Medicine | 5 |
| Critical care (intensivists) | 5 |
| Centralized Flu | 4 |
| Neurosurgery | 4 |
| Pharmacy | 4 |
| Interventional Cardiology | 4 |
| Hematology | 3 |
| Medical oncology | 3 |
| Interventional Pain Management (IPM) | 3 |
| Pain Management | 3 |
| Micrographic Dermatologic Surgery | 3 |
| Hand surgery | 3 |
| Addiction medicine | 3 |
| Gynecologist/oncologist | 2 |
| Registered Dietician/Nutrition Professional | 2 |
| Colorectal surgery (formerly proctology) | 2 |
| Epileptologists | 2 |
| Vascular surgery | 2 |
| Advanced Heart Failure and Transplant Cardiology | 1 |
| Medicare Diabetes Preventive Program | 1 |
| General Psychiatry | 1 |
| Ambulatory Surgical Center | 1 |
| Maxillofacial surgery | 1 |
| Opioid Treatment Program | 1 |
| Oral surgery (dentists only) | 1 |
| Osteopathic manipulative therapy | 1 |
| Ambulance Service Supplier, e.g., private ambulance companies, funeral homes | 1 |
| Medical Genetics and Genomics | 1 |