| Nurse practitioner | 1,847 |
| Physical therapist (private practice) | 1,519 |
| Internal medicine | 1,079 |
| Physician assistant | 957 |
| Licensed clinical social worker | 856 |
| Chiropractic | 527 |
| Family practice | 491 |
| Occupational therapist (private practice) | 479 |
| Anesthesiology | 475 |
| Obstetrics/gynecology | 331 |
| Emergency medicine | 330 |
| Optometrist | 297 |
| Diagnostic Radiology | 295 |
| Clinical psychologist | 287 |
| Podiatry | 281 |
| Mental Health Counselors | 277 |
| Cardiology | 269 |
| Psychiatry | 247 |
| Certified Registered Nurse Anesthetist (CRNA) | 233 |
| Mass Immunization Roster Billers | 230 |
| Orthopedic surgery | 188 |
| General surgery | 176 |
| Neurology | 174 |
| Ophthalmology | 165 |
| Gastroenterology | 161 |
| Physical medicine and rehabilitation | 141 |
| Pulmonary disease | 122 |
| Speech / language pathology | 109 |
| Dermatology | 107 |
| Otolaryngology | 103 |
| Endocrinology | 93 |
| Hematology/oncology | 92 |
| Urology | 86 |
| Nephrology | 84 |
| Centralized Flu | 83 |
| Pathology | 82 |
| Pediatric medicine | 82 |
| Infectious disease | 76 |
| Ambulance Service Supplier, e.g., private ambulance companies, funeral homes | 71 |
| Ambulatory Surgical Center | 69 |
| Registered Dietician/Nutrition Professional | 66 |
| Audiologist (billing independently) | 58 |
| Vascular surgery | 52 |
| Pharmacy | 48 |
| Medical oncology | 47 |
| Plastic and reconstructive surgery | 47 |
| Neurosurgery | 46 |
| Rheumatology | 46 |
| Radiation oncology | 44 |
| Interventional radiology | 43 |
| Hospitalist | 43 |
| Pain Management | 43 |
| Allergy/immunology | 41 |
| Marriage and Family Therapist | 38 |
| Thoracic surgery | 33 |
| Interventional Cardiology | 32 |
| Certified nurse midwife | 30 |
| Clinical Laboratory (Billing Independently) | 28 |
| Geriatric medicine | 26 |
| Surgical oncology | 25 |
| Sports Medicine | 24 |
| Independent Diagnostic Testing Facility (IDTF) | 24 |
| Cardiac Electrophysiology | 24 |
| Critical care (intensivists) | 23 |
| Interventional Pain Management (IPM) | 22 |
| Colorectal surgery (formerly proctology) | 21 |
| Oral surgery (dentists only) | 19 |
| Hand surgery | 17 |
| Certified clinical nurse specialist | 12 |
| General practice | 11 |
| Opioid Treatment Program | 10 |
| Gynecologist/oncologist | 10 |
| Hospice and Palliative Care | 9 |
| Osteopathic manipulative therapy | 9 |
| Cardiac surgery | 8 |
| Hematology | 7 |
| Addiction medicine | 5 |
| Portable X-Ray Supplier (Billing Independently) | 5 |
| Sleep Medicine | 5 |
| Home Infusion Therapy Services | 5 |
| Dentist | 4 |
| Micrographic Dermatologic Surgery | 4 |
| Preventive medicine | 4 |
| Nuclear medicine | 4 |
| Single or Multispecialty Clinic or Group Practice | 4 |
| General Psychiatry | 3 |
| Epileptologists | 3 |
| Advanced Heart Failure and Transplant Cardiology | 2 |
| Psychologist (billing independently) | 2 |
| Public Health or Welfare Agencies (Federal, State, and local) | 1 |
| Hematopoietic Cell Transplantation and Cellular Therapy | 1 |
| Medical Genetics and Genomics | 1 |
| Oral Medicine | 1 |
| Neuropsychiatry | 1 |
| Maxillofacial surgery | 1 |