| Nurse practitioner | 2,455 |
| Physician assistant | 813 |
| Family practice | 757 |
| Internal medicine | 671 |
| Physical therapist (private practice) | 581 |
| Emergency medicine | 405 |
| Certified Registered Nurse Anesthetist (CRNA) | 392 |
| Licensed clinical social worker | 377 |
| Anesthesiology | 355 |
| Optometrist | 338 |
| Diagnostic Radiology | 288 |
| Hospitalist | 274 |
| Chiropractic | 249 |
| Obstetrics/gynecology | 247 |
| Mass Immunization Roster Billers | 222 |
| Mental Health Counselors | 210 |
| Psychiatry | 181 |
| Clinical psychologist | 181 |
| General surgery | 159 |
| Neurology | 157 |
| Orthopedic surgery | 138 |
| Cardiology | 131 |
| Ophthalmology | 122 |
| Gastroenterology | 119 |
| Pulmonary disease | 119 |
| Occupational therapist (private practice) | 110 |
| Pathology | 108 |
| Podiatry | 103 |
| Ambulance Service Supplier, e.g., private ambulance companies, funeral homes | 96 |
| Dermatology | 94 |
| Physical medicine and rehabilitation | 74 |
| Urology | 73 |
| Anesthesiologist Assistant | 73 |
| Audiologist (billing independently) | 72 |
| Otolaryngology | 69 |
| Nephrology | 67 |
| Medical oncology | 65 |
| Endocrinology | 59 |
| Infectious disease | 53 |
| Hematology | 51 |
| Neurosurgery | 46 |
| Registered Dietician/Nutrition Professional | 43 |
| Radiation oncology | 43 |
| Ambulatory Surgical Center | 40 |
| Sports Medicine | 40 |
| Pediatric medicine | 40 |
| Speech / language pathology | 39 |
| Hematology/oncology | 39 |
| Rheumatology | 38 |
| Plastic and reconstructive surgery | 37 |
| Hospice and Palliative Care | 35 |
| Critical care (intensivists) | 35 |
| Centralized Flu | 35 |
| Certified nurse midwife | 35 |
| Interventional Cardiology | 32 |
| Allergy/immunology | 30 |
| Vascular surgery | 29 |
| Cardiac Electrophysiology | 25 |
| Interventional radiology | 25 |
| Sleep Medicine | 22 |
| Advanced Heart Failure and Transplant Cardiology | 20 |
| Surgical oncology | 20 |
| Colorectal surgery (formerly proctology) | 19 |
| Thoracic surgery | 17 |
| Certified clinical nurse specialist | 16 |
| General practice | 14 |
| Pain Management | 14 |
| Hand surgery | 13 |
| Gynecologist/oncologist | 13 |
| Pharmacy | 12 |
| Independent Diagnostic Testing Facility (IDTF) | 11 |
| Addiction medicine | 10 |
| Cardiac surgery | 8 |
| Opioid Treatment Program | 8 |
| Clinical Laboratory (Billing Independently) | 8 |
| Maxillofacial surgery | 7 |
| Geriatric medicine | 7 |
| Interventional Pain Management (IPM) | 6 |
| Epileptologists | 5 |
| Single or Multispecialty Clinic or Group Practice | 5 |
| Oral surgery (dentists only) | 5 |
| Hematopoietic Cell Transplantation and Cellular Therapy | 4 |
| Adult Congenital Heart Disease | 4 |
| Unknown Provider | 3 |
| Osteopathic manipulative therapy | 3 |
| Public Health or Welfare Agencies (Federal, State, and local) | 3 |
| Nuclear medicine | 3 |
| Preventive medicine | 2 |
| Medical Genetics and Genomics | 2 |
| Unknown physician specialty | 2 |
| Micrographic Dermatologic Surgery | 1 |
| Home Infusion Therapy Services | 1 |
| Marriage and Family Therapist | 1 |
| Medical Toxicology | 1 |
| Dentist | 1 |
| Psychologist (billing independently) | 1 |