| Nurse practitioner | 2,199 |
| Physician assistant | 1,757 |
| Internal medicine | 1,142 |
| Licensed clinical social worker | 1,035 |
| Physical therapist (private practice) | 778 |
| Emergency medicine | 441 |
| Anesthesiology | 411 |
| Family practice | 390 |
| Certified Registered Nurse Anesthetist (CRNA) | 389 |
| Psychiatry | 365 |
| Mental Health Counselors | 364 |
| Obstetrics/gynecology | 359 |
| Optometrist | 315 |
| Clinical psychologist | 309 |
| Diagnostic Radiology | 284 |
| Cardiology | 248 |
| Chiropractic | 242 |
| Orthopedic surgery | 221 |
| Mass Immunization Roster Billers | 219 |
| Hospitalist | 209 |
| General surgery | 192 |
| Neurology | 187 |
| Gastroenterology | 178 |
| Occupational therapist (private practice) | 152 |
| Pathology | 150 |
| Podiatry | 149 |
| Ophthalmology | 149 |
| Pulmonary disease | 138 |
| Dermatology | 127 |
| Marriage and Family Therapist | 120 |
| Centralized Flu | 108 |
| Endocrinology | 97 |
| Pediatric medicine | 95 |
| Urology | 90 |
| Infectious disease | 88 |
| Ambulance Service Supplier, e.g., private ambulance companies, funeral homes | 86 |
| Physical medicine and rehabilitation | 80 |
| Otolaryngology | 80 |
| Certified nurse midwife | 75 |
| Audiologist (billing independently) | 75 |
| Nephrology | 74 |
| Hematology/oncology | 70 |
| Neurosurgery | 55 |
| Vascular surgery | 51 |
| Rheumatology | 47 |
| Medical oncology | 47 |
| Plastic and reconstructive surgery | 42 |
| Registered Dietician/Nutrition Professional | 42 |
| Geriatric medicine | 41 |
| Radiation oncology | 40 |
| Ambulatory Surgical Center | 32 |
| Interventional Cardiology | 30 |
| Pharmacy | 30 |
| Colorectal surgery (formerly proctology) | 29 |
| Allergy/immunology | 28 |
| Speech / language pathology | 26 |
| Critical care (intensivists) | 25 |
| Thoracic surgery | 23 |
| Certified clinical nurse specialist | 22 |
| Cardiac Electrophysiology | 22 |
| Hand surgery | 20 |
| Pain Management | 20 |
| Interventional radiology | 19 |
| Sports Medicine | 17 |
| Gynecologist/oncologist | 16 |
| Hospice and Palliative Care | 14 |
| Oral surgery (dentists only) | 14 |
| Surgical oncology | 14 |
| General practice | 13 |
| Opioid Treatment Program | 12 |
| Cardiac surgery | 11 |
| Interventional Pain Management (IPM) | 11 |
| Clinical Laboratory (Billing Independently) | 9 |
| Osteopathic manipulative therapy | 8 |
| Micrographic Dermatologic Surgery | 8 |
| Addiction medicine | 8 |
| Hematology | 8 |
| Sleep Medicine | 6 |
| Independent Diagnostic Testing Facility (IDTF) | 6 |
| General Psychiatry | 6 |
| Maxillofacial surgery | 6 |
| Advanced Heart Failure and Transplant Cardiology | 4 |
| Nuclear medicine | 4 |
| Medical Genetics and Genomics | 3 |
| Neuropsychiatry | 2 |
| Radiation Therapy Centers | 2 |
| Epileptologists | 1 |
| Unknown Provider | 1 |
| Unknown physician specialty | 1 |
| Home Infusion Therapy Services | 1 |
| Portable X-Ray Supplier (Billing Independently) | 1 |
| Preventive medicine | 1 |
| Dentist | 1 |
| Single or Multispecialty Clinic or Group Practice | 1 |
| Psychologist (billing independently) | 1 |
| Oral and Maxillofacial Pathology | 1 |