| Physical therapist (private practice) | 1,309 |
| Nurse practitioner | 1,251 |
| Internal medicine | 1,116 |
| Family practice | 1,098 |
| Physician assistant | 1,036 |
| Emergency medicine | 636 |
| Anesthesiology | 534 |
| Clinical psychologist | 480 |
| Diagnostic Radiology | 340 |
| Psychiatry | 338 |
| Licensed clinical social worker | 301 |
| Chiropractic | 301 |
| Obstetrics/gynecology | 301 |
| Hospitalist | 296 |
| Optometrist | 289 |
| Marriage and Family Therapist | 285 |
| Orthopedic surgery | 245 |
| Ophthalmology | 238 |
| Dermatology | 217 |
| Cardiology | 191 |
| General surgery | 189 |
| Mass Immunization Roster Billers | 187 |
| Neurology | 181 |
| Occupational therapist (private practice) | 179 |
| Certified Registered Nurse Anesthetist (CRNA) | 153 |
| Gastroenterology | 146 |
| Podiatry | 135 |
| Pathology | 127 |
| Hematology/oncology | 127 |
| Urology | 116 |
| Otolaryngology | 110 |
| Pulmonary disease | 107 |
| Nephrology | 102 |
| Critical care (intensivists) | 99 |
| Physical medicine and rehabilitation | 82 |
| Speech / language pathology | 72 |
| Endocrinology | 71 |
| Audiologist (billing independently) | 68 |
| Infectious disease | 68 |
| Radiation oncology | 62 |
| Rheumatology | 57 |
| General practice | 56 |
| Geriatric medicine | 54 |
| Interventional radiology | 54 |
| Mental Health Counselors | 50 |
| Neurosurgery | 49 |
| Registered Dietician/Nutrition Professional | 48 |
| Ambulatory Surgical Center | 47 |
| Plastic and reconstructive surgery | 47 |
| Allergy/immunology | 46 |
| Pediatric medicine | 40 |
| Centralized Flu | 37 |
| Vascular surgery | 35 |
| Interventional Cardiology | 35 |
| Pain Management | 35 |
| Clinical Laboratory (Billing Independently) | 33 |
| Hospice and Palliative Care | 27 |
| Ambulance Service Supplier, e.g., private ambulance companies, funeral homes | 26 |
| Cardiac Electrophysiology | 24 |
| Psychologist (billing independently) | 23 |
| Thoracic surgery | 23 |
| Preventive medicine | 22 |
| Osteopathic manipulative therapy | 20 |
| Pharmacy | 20 |
| Hand surgery | 20 |
| Sports Medicine | 20 |
| Certified nurse midwife | 18 |
| Advanced Heart Failure and Transplant Cardiology | 17 |
| Medical oncology | 14 |
| Colorectal surgery (formerly proctology) | 12 |
| Sleep Medicine | 12 |
| Cardiac surgery | 11 |
| Independent Diagnostic Testing Facility (IDTF) | 11 |
| Interventional Pain Management (IPM) | 11 |
| Surgical oncology | 10 |
| Nuclear medicine | 10 |
| Unknown physician specialty | 10 |
| Oral surgery (dentists only) | 10 |
| Opioid Treatment Program | 10 |
| Neuropsychiatry | 8 |
| Gynecologist/oncologist | 8 |
| Micrographic Dermatologic Surgery | 8 |
| Dentist | 6 |
| Hematology | 6 |
| Maxillofacial surgery | 4 |
| Portable X-Ray Supplier (Billing Independently) | 4 |
| Medical Genetics and Genomics | 4 |
| Unknown Provider | 2 |
| Undersea and Hyperbaric Medicine | 2 |
| Addiction medicine | 2 |
| General Psychiatry | 2 |
| Adult Congenital Heart Disease | 2 |
| Epileptologists | 2 |
| Single or Multispecialty Clinic or Group Practice | 1 |
| Oral Medicine | 1 |