| Nurse practitioner | 869 |
| Physical therapist (private practice) | 643 |
| Internal medicine | 572 |
| Physician assistant | 476 |
| Licensed clinical social worker | 329 |
| Family practice | 287 |
| Anesthesiology | 259 |
| Chiropractic | 245 |
| Emergency medicine | 219 |
| Obstetrics/gynecology | 177 |
| Clinical psychologist | 166 |
| Optometrist | 158 |
| Occupational therapist (private practice) | 156 |
| Cardiology | 149 |
| Diagnostic Radiology | 146 |
| Psychiatry | 141 |
| Podiatry | 129 |
| Certified Registered Nurse Anesthetist (CRNA) | 123 |
| Mass Immunization Roster Billers | 109 |
| Mental Health Counselors | 106 |
| Orthopedic surgery | 105 |
| Ophthalmology | 98 |
| General surgery | 92 |
| Gastroenterology | 82 |
| Neurology | 79 |
| Physical medicine and rehabilitation | 67 |
| Dermatology | 61 |
| Hematology/oncology | 54 |
| Nephrology | 52 |
| Urology | 52 |
| Pathology | 50 |
| Endocrinology | 49 |
| Infectious disease | 49 |
| Pulmonary disease | 44 |
| Otolaryngology | 43 |
| Ambulance Service Supplier, e.g., private ambulance companies, funeral homes | 42 |
| Centralized Flu | 42 |
| Pediatric medicine | 41 |
| Speech / language pathology | 41 |
| Rheumatology | 36 |
| Hospitalist | 32 |
| Audiologist (billing independently) | 31 |
| Critical care (intensivists) | 26 |
| Plastic and reconstructive surgery | 26 |
| Allergy/immunology | 25 |
| Registered Dietician/Nutrition Professional | 24 |
| Ambulatory Surgical Center | 23 |
| Neurosurgery | 21 |
| Vascular surgery | 21 |
| Interventional Cardiology | 20 |
| Radiation oncology | 20 |
| Medical oncology | 17 |
| Pain Management | 17 |
| Marriage and Family Therapist | 15 |
| Pharmacy | 14 |
| Cardiac Electrophysiology | 13 |
| Interventional radiology | 12 |
| Certified nurse midwife | 12 |
| Geriatric medicine | 12 |
| Oral surgery (dentists only) | 11 |
| Surgical oncology | 10 |
| Thoracic surgery | 10 |
| Sports Medicine | 10 |
| Colorectal surgery (formerly proctology) | 8 |
| Certified clinical nurse specialist | 7 |
| Clinical Laboratory (Billing Independently) | 7 |
| Hand surgery | 6 |
| General practice | 5 |
| Opioid Treatment Program | 5 |
| Gynecologist/oncologist | 5 |
| Nuclear medicine | 4 |
| Hematology | 4 |
| Independent Diagnostic Testing Facility (IDTF) | 4 |
| Sleep Medicine | 3 |
| Dentist | 3 |
| Cardiac surgery | 3 |
| Hospice and Palliative Care | 2 |
| Maxillofacial surgery | 2 |
| General Psychiatry | 2 |
| Advanced Heart Failure and Transplant Cardiology | 2 |
| Micrographic Dermatologic Surgery | 1 |
| Osteopathic manipulative therapy | 1 |
| Single or Multispecialty Clinic or Group Practice | 1 |
| Interventional Pain Management (IPM) | 1 |
| Medicare Diabetes Preventive Program | 1 |
| Psychologist (billing independently) | 1 |
| Epileptologists | 1 |