| Nurse practitioner | 13,238 |
| Physician assistant | 5,412 |
| Internal medicine | 4,784 |
| Family practice | 3,528 |
| Certified Registered Nurse Anesthetist (CRNA) | 3,242 |
| Physical therapist (private practice) | 2,693 |
| Emergency medicine | 2,314 |
| Anesthesiology | 1,831 |
| Licensed clinical social worker | 1,716 |
| Diagnostic Radiology | 1,597 |
| Chiropractic | 1,482 |
| Obstetrics/gynecology | 1,383 |
| Mental Health Counselors | 1,255 |
| Optometrist | 1,204 |
| Centralized Flu | 1,087 |
| Cardiology | 1,023 |
| Clinical psychologist | 954 |
| Orthopedic surgery | 928 |
| Psychiatry | 876 |
| Mass Immunization Roster Billers | 869 |
| General surgery | 861 |
| Hospitalist | 841 |
| Ophthalmology | 833 |
| Podiatry | 806 |
| Gastroenterology | 800 |
| Neurology | 797 |
| General practice | 753 |
| Dermatology | 698 |
| Occupational therapist (private practice) | 660 |
| Anesthesiologist Assistant | 553 |
| Pathology | 522 |
| Pulmonary disease | 499 |
| Urology | 498 |
| Hematology/oncology | 463 |
| Otolaryngology | 409 |
| Nephrology | 407 |
| Physical medicine and rehabilitation | 404 |
| Critical care (intensivists) | 369 |
| Infectious disease | 362 |
| Pediatric medicine | 335 |
| Ambulatory Surgical Center | 333 |
| Endocrinology | 304 |
| Audiologist (billing independently) | 295 |
| Interventional Cardiology | 269 |
| Neurosurgery | 269 |
| Radiation oncology | 268 |
| Speech / language pathology | 265 |
| Rheumatology | 229 |
| Plastic and reconstructive surgery | 215 |
| Vascular surgery | 206 |
| Pain Management | 182 |
| Thoracic surgery | 162 |
| Registered Dietician/Nutrition Professional | 160 |
| Certified nurse midwife | 154 |
| Cardiac Electrophysiology | 154 |
| Medical oncology | 143 |
| Ambulance Service Supplier, e.g., private ambulance companies, funeral homes | 142 |
| Allergy/immunology | 135 |
| Interventional radiology | 133 |
| Marriage and Family Therapist | 131 |
| Independent Diagnostic Testing Facility (IDTF) | 126 |
| Interventional Pain Management (IPM) | 125 |
| Pharmacy | 122 |
| Clinical Laboratory (Billing Independently) | 113 |
| Colorectal surgery (formerly proctology) | 94 |
| Hand surgery | 86 |
| Sports Medicine | 77 |
| Surgical oncology | 71 |
| Hospice and Palliative Care | 70 |
| Gynecologist/oncologist | 55 |
| Geriatric medicine | 52 |
| Oral surgery (dentists only) | 47 |
| Osteopathic manipulative therapy | 46 |
| Cardiac surgery | 40 |
| Opioid Treatment Program | 37 |
| Psychologist (billing independently) | 35 |
| Advanced Heart Failure and Transplant Cardiology | 30 |
| Micrographic Dermatologic Surgery | 30 |
| Hematology | 29 |
| Maxillofacial surgery | 21 |
| Medical Genetics and Genomics | 19 |
| Neuropsychiatry | 16 |
| Sleep Medicine | 15 |
| Portable X-Ray Supplier (Billing Independently) | 14 |
| Nuclear medicine | 14 |
| Preventive medicine | 11 |
| Epileptologists | 10 |
| Home Infusion Therapy Services | 9 |
| Addiction medicine | 7 |
| General Psychiatry | 7 |
| Peripheral vascular disease | 5 |
| Certified clinical nurse specialist | 5 |
| Single or Multispecialty Clinic or Group Practice | 5 |
| Unknown physician specialty | 4 |
| Hematopoietic Cell Transplantation and Cellular Therapy | 4 |
| Undersea and Hyperbaric Medicine | 3 |
| Dentist | 3 |
| Mammography Screening Center | 3 |
| Unknown Provider | 3 |
| Medicare Diabetes Preventive Program | 3 |
| Oral and Maxillofacial Radiology | 1 |
| Oral and Maxillofacial Pathology | 1 |
| Oral Medicine | 1 |