| Physician assistant | 2,512 |
| Nurse practitioner | 2,273 |
| Physical therapist (private practice) | 1,827 |
| Licensed clinical social worker | 1,281 |
| Internal medicine | 1,158 |
| Anesthesiology | 841 |
| Family practice | 725 |
| Diagnostic Radiology | 704 |
| Clinical psychologist | 559 |
| Emergency medicine | 552 |
| Psychiatry | 500 |
| Obstetrics/gynecology | 474 |
| Certified Registered Nurse Anesthetist (CRNA) | 438 |
| Chiropractic | 433 |
| Cardiology | 427 |
| Occupational therapist (private practice) | 423 |
| Hospitalist | 410 |
| Podiatry | 333 |
| Orthopedic surgery | 309 |
| Pathology | 287 |
| Gastroenterology | 286 |
| Neurology | 285 |
| General surgery | 276 |
| Ophthalmology | 271 |
| Optometrist | 232 |
| Mass Immunization Roster Billers | 230 |
| Mental Health Counselors | 227 |
| Dermatology | 223 |
| Physical medicine and rehabilitation | 169 |
| Pulmonary disease | 162 |
| Hematology/oncology | 161 |
| Urology | 159 |
| Endocrinology | 154 |
| Audiologist (billing independently) | 151 |
| Pediatric medicine | 133 |
| Nephrology | 130 |
| Speech / language pathology | 128 |
| Otolaryngology | 127 |
| Ambulance Service Supplier, e.g., private ambulance companies, funeral homes | 117 |
| Plastic and reconstructive surgery | 115 |
| Registered Dietician/Nutrition Professional | 108 |
| Critical care (intensivists) | 102 |
| Infectious disease | 92 |
| Neurosurgery | 91 |
| Rheumatology | 88 |
| Centralized Flu | 80 |
| Interventional Cardiology | 73 |
| Allergy/immunology | 73 |
| Medical oncology | 72 |
| Vascular surgery | 66 |
| Radiation oncology | 61 |
| Interventional radiology | 59 |
| Pain Management | 55 |
| Colorectal surgery (formerly proctology) | 50 |
| Thoracic surgery | 46 |
| Cardiac Electrophysiology | 42 |
| Oral surgery (dentists only) | 37 |
| Geriatric medicine | 35 |
| Clinical Laboratory (Billing Independently) | 35 |
| Certified nurse midwife | 34 |
| Ambulatory Surgical Center | 33 |
| Hospice and Palliative Care | 33 |
| Pharmacy | 32 |
| Nuclear medicine | 32 |
| Surgical oncology | 32 |
| Gynecologist/oncologist | 24 |
| General practice | 24 |
| Osteopathic manipulative therapy | 21 |
| Independent Diagnostic Testing Facility (IDTF) | 21 |
| Sports Medicine | 20 |
| Interventional Pain Management (IPM) | 20 |
| Hand surgery | 19 |
| Cardiac surgery | 17 |
| Advanced Heart Failure and Transplant Cardiology | 15 |
| Hematology | 15 |
| Maxillofacial surgery | 12 |
| Marriage and Family Therapist | 11 |
| Certified clinical nurse specialist | 8 |
| Micrographic Dermatologic Surgery | 8 |
| Medical Genetics and Genomics | 7 |
| General Psychiatry | 6 |
| Portable X-Ray Supplier (Billing Independently) | 6 |
| Addiction medicine | 5 |
| Opioid Treatment Program | 5 |
| Epileptologists | 5 |
| Sleep Medicine | 5 |
| Single or Multispecialty Clinic or Group Practice | 5 |
| Medical Toxicology | 4 |
| Unknown physician specialty | 4 |
| Dentist | 3 |
| Hematopoietic Cell Transplantation and Cellular Therapy | 3 |
| Preventive medicine | 3 |
| Home Infusion Therapy Services | 3 |
| Undersea and Hyperbaric Medicine | 2 |
| Adult Congenital Heart Disease | 2 |
| Neuropsychiatry | 2 |
| Unknown Provider | 1 |
| Radiation Therapy Centers | 1 |
| Oral and Maxillofacial Pathology | 1 |
| Peripheral vascular disease | 1 |