| Nurse practitioner | 1,431 |
| Physician assistant | 628 |
| Family practice | 444 |
| Internal medicine | 426 |
| Anesthesiology | 335 |
| Physical therapist (private practice) | 326 |
| Emergency medicine | 268 |
| Licensed clinical social worker | 250 |
| Optometrist | 215 |
| Obstetrics/gynecology | 173 |
| Diagnostic Radiology | 171 |
| Chiropractic | 127 |
| Mass Immunization Roster Billers | 120 |
| Orthopedic surgery | 117 |
| Mental Health Counselors | 111 |
| General surgery | 103 |
| Clinical psychologist | 100 |
| Occupational therapist (private practice) | 96 |
| Cardiology | 95 |
| Neurology | 91 |
| Gastroenterology | 79 |
| Pulmonary disease | 76 |
| Hospitalist | 76 |
| Psychiatry | 69 |
| Certified Registered Nurse Anesthetist (CRNA) | 62 |
| Pathology | 56 |
| Ophthalmology | 56 |
| Podiatry | 55 |
| Audiologist (billing independently) | 52 |
| Pediatric medicine | 51 |
| Otolaryngology | 51 |
| Dermatology | 50 |
| Nephrology | 46 |
| Speech / language pathology | 45 |
| Urology | 41 |
| Anesthesiologist Assistant | 40 |
| Infectious disease | 39 |
| Endocrinology | 39 |
| Hematology/oncology | 37 |
| Ambulatory Surgical Center | 35 |
| Ambulance Service Supplier, e.g., private ambulance companies, funeral homes | 33 |
| Interventional Cardiology | 33 |
| Centralized Flu | 30 |
| Pharmacy | 29 |
| Registered Dietician/Nutrition Professional | 28 |
| Rheumatology | 27 |
| Radiation oncology | 26 |
| Plastic and reconstructive surgery | 25 |
| Physical medicine and rehabilitation | 24 |
| Critical care (intensivists) | 24 |
| Medical oncology | 22 |
| Neurosurgery | 18 |
| Interventional radiology | 18 |
| Hospice and Palliative Care | 17 |
| Vascular surgery | 17 |
| Thoracic surgery | 15 |
| Sports Medicine | 15 |
| Certified nurse midwife | 15 |
| Pain Management | 15 |
| Geriatric medicine | 14 |
| Colorectal surgery (formerly proctology) | 14 |
| Maxillofacial surgery | 14 |
| Marriage and Family Therapist | 13 |
| Certified clinical nurse specialist | 13 |
| Cardiac Electrophysiology | 11 |
| Sleep Medicine | 10 |
| Allergy/immunology | 10 |
| Independent Diagnostic Testing Facility (IDTF) | 10 |
| Advanced Heart Failure and Transplant Cardiology | 8 |
| Hand surgery | 8 |
| Surgical oncology | 7 |
| Osteopathic manipulative therapy | 6 |
| Interventional Pain Management (IPM) | 6 |
| Oral surgery (dentists only) | 6 |
| Cardiac surgery | 5 |
| Clinical Laboratory (Billing Independently) | 3 |
| Hematology | 3 |
| Addiction medicine | 3 |
| Gynecologist/oncologist | 3 |
| Medical Genetics and Genomics | 3 |
| Preventive medicine | 3 |
| Nuclear medicine | 3 |
| General practice | 3 |
| Opioid Treatment Program | 3 |
| Neuropsychiatry | 1 |
| Micrographic Dermatologic Surgery | 1 |
| Single or Multispecialty Clinic or Group Practice | 1 |
| Hematopoietic Cell Transplantation and Cellular Therapy | 1 |
| General Psychiatry | 1 |
| Portable X-Ray Supplier (Billing Independently) | 1 |