| Nurse practitioner | 5,627 |
| Physician assistant | 1,670 |
| Certified Registered Nurse Anesthetist (CRNA) | 1,454 |
| Internal medicine | 1,419 |
| Physical therapist (private practice) | 1,300 |
| Family practice | 1,083 |
| Emergency medicine | 681 |
| Optometrist | 556 |
| Mass Immunization Roster Billers | 466 |
| Diagnostic Radiology | 463 |
| Chiropractic | 452 |
| Anesthesiology | 439 |
| Obstetrics/gynecology | 392 |
| Licensed clinical social worker | 368 |
| General surgery | 340 |
| Orthopedic surgery | 310 |
| Psychiatry | 238 |
| Cardiology | 232 |
| Occupational therapist (private practice) | 232 |
| Neurology | 214 |
| Centralized Flu | 212 |
| Mental Health Counselors | 209 |
| Ophthalmology | 205 |
| Clinical psychologist | 183 |
| Hospitalist | 174 |
| Pathology | 170 |
| Pulmonary disease | 161 |
| Gastroenterology | 157 |
| Audiologist (billing independently) | 153 |
| Podiatry | 151 |
| Hematology/oncology | 144 |
| Dermatology | 124 |
| Otolaryngology | 119 |
| Urology | 115 |
| Speech / language pathology | 111 |
| Ambulatory Surgical Center | 102 |
| Interventional Cardiology | 100 |
| Ambulance Service Supplier, e.g., private ambulance companies, funeral homes | 95 |
| Nephrology | 94 |
| Pharmacy | 85 |
| Physical medicine and rehabilitation | 80 |
| Infectious disease | 79 |
| Neurosurgery | 76 |
| Pediatric medicine | 74 |
| Endocrinology | 67 |
| Radiation oncology | 66 |
| Vascular surgery | 62 |
| Plastic and reconstructive surgery | 61 |
| Rheumatology | 60 |
| Registered Dietician/Nutrition Professional | 59 |
| Allergy/immunology | 57 |
| Certified nurse midwife | 57 |
| Medical oncology | 44 |
| Marriage and Family Therapist | 43 |
| Critical care (intensivists) | 42 |
| Cardiac Electrophysiology | 38 |
| General practice | 36 |
| Thoracic surgery | 35 |
| Sports Medicine | 34 |
| Pain Management | 32 |
| Interventional radiology | 28 |
| Clinical Laboratory (Billing Independently) | 25 |
| Hand surgery | 24 |
| Surgical oncology | 24 |
| Cardiac surgery | 22 |
| Oral surgery (dentists only) | 20 |
| Independent Diagnostic Testing Facility (IDTF) | 20 |
| Hospice and Palliative Care | 19 |
| Addiction medicine | 19 |
| Opioid Treatment Program | 18 |
| Geriatric medicine | 15 |
| Interventional Pain Management (IPM) | 15 |
| Gynecologist/oncologist | 14 |
| Sleep Medicine | 14 |
| Colorectal surgery (formerly proctology) | 12 |
| Unknown Provider | 12 |
| Maxillofacial surgery | 12 |
| Osteopathic manipulative therapy | 11 |
| Micrographic Dermatologic Surgery | 11 |
| Hematology | 10 |
| Psychologist (billing independently) | 8 |
| Advanced Heart Failure and Transplant Cardiology | 7 |
| Certified clinical nurse specialist | 6 |
| Neuropsychiatry | 3 |
| Nuclear medicine | 3 |
| Medical Genetics and Genomics | 2 |
| Unknown physician specialty | 2 |
| Portable X-Ray Supplier (Billing Independently) | 2 |
| Radiation Therapy Centers | 1 |
| Undersea and Hyperbaric Medicine | 1 |
| Medicare Diabetes Preventive Program | 1 |
| Preventive medicine | 1 |
| Home Infusion Therapy Services | 1 |