| Nurse practitioner | 4,451 |
| Internal medicine | 1,828 |
| Physician assistant | 1,738 |
| Family practice | 1,680 |
| Anesthesiology | 1,041 |
| Certified Registered Nurse Anesthetist (CRNA) | 1,031 |
| Emergency medicine | 960 |
| Optometrist | 793 |
| Diagnostic Radiology | 779 |
| Physical therapist (private practice) | 719 |
| Obstetrics/gynecology | 672 |
| Hospitalist | 549 |
| Mass Immunization Roster Billers | 509 |
| Cardiology | 494 |
| Mental Health Counselors | 444 |
| Psychiatry | 441 |
| Pathology | 431 |
| Orthopedic surgery | 418 |
| Neurology | 415 |
| General surgery | 415 |
| Licensed clinical social worker | 365 |
| Gastroenterology | 348 |
| Ophthalmology | 330 |
| Chiropractic | 321 |
| Dermatology | 306 |
| Podiatry | 263 |
| Clinical psychologist | 248 |
| Nephrology | 243 |
| Hematology/oncology | 227 |
| Otolaryngology | 225 |
| Centralized Flu | 219 |
| Anesthesiologist Assistant | 216 |
| Urology | 199 |
| Pulmonary disease | 196 |
| Endocrinology | 185 |
| Physical medicine and rehabilitation | 176 |
| Critical care (intensivists) | 171 |
| Infectious disease | 166 |
| Pediatric medicine | 165 |
| Medical oncology | 155 |
| Ambulance Service Supplier, e.g., private ambulance companies, funeral homes | 154 |
| Radiation oncology | 153 |
| Rheumatology | 148 |
| Occupational therapist (private practice) | 134 |
| Neurosurgery | 130 |
| Audiologist (billing independently) | 127 |
| Interventional Cardiology | 120 |
| Plastic and reconstructive surgery | 114 |
| Speech / language pathology | 99 |
| Ambulatory Surgical Center | 87 |
| Allergy/immunology | 85 |
| Vascular surgery | 82 |
| General practice | 78 |
| Thoracic surgery | 70 |
| Interventional radiology | 69 |
| Registered Dietician/Nutrition Professional | 67 |
| Hospice and Palliative Care | 66 |
| Pain Management | 64 |
| Clinical Laboratory (Billing Independently) | 63 |
| Independent Diagnostic Testing Facility (IDTF) | 62 |
| Cardiac Electrophysiology | 53 |
| Colorectal surgery (formerly proctology) | 52 |
| Surgical oncology | 49 |
| Geriatric medicine | 48 |
| Gynecologist/oncologist | 39 |
| Sports Medicine | 38 |
| Marriage and Family Therapist | 37 |
| Pharmacy | 34 |
| Hematology | 32 |
| Interventional Pain Management (IPM) | 30 |
| Hand surgery | 29 |
| Certified nurse midwife | 25 |
| Cardiac surgery | 19 |
| Nuclear medicine | 19 |
| Oral surgery (dentists only) | 17 |
| Advanced Heart Failure and Transplant Cardiology | 16 |
| Certified clinical nurse specialist | 16 |
| Hematopoietic Cell Transplantation and Cellular Therapy | 15 |
| Maxillofacial surgery | 13 |
| Medical Genetics and Genomics | 13 |
| Preventive medicine | 10 |
| Micrographic Dermatologic Surgery | 9 |
| Opioid Treatment Program | 8 |
| Epileptologists | 8 |
| Portable X-Ray Supplier (Billing Independently) | 7 |
| Sleep Medicine | 7 |
| Osteopathic manipulative therapy | 6 |
| Home Infusion Therapy Services | 4 |
| Addiction medicine | 4 |
| General Psychiatry | 3 |
| Psychologist (billing independently) | 2 |
| Dentist | 2 |
| Neuropsychiatry | 2 |
| Undersea and Hyperbaric Medicine | 1 |
| Oral and Maxillofacial Pathology | 1 |
| Single or Multispecialty Clinic or Group Practice | 1 |