| Nurse practitioner | 6,254 |
| Physician assistant | 5,335 |
| Internal medicine | 2,774 |
| Family practice | 2,765 |
| Physical therapist (private practice) | 2,431 |
| Certified Registered Nurse Anesthetist (CRNA) | 2,308 |
| Emergency medicine | 1,481 |
| Licensed clinical social worker | 1,245 |
| Anesthesiology | 1,219 |
| Chiropractic | 1,217 |
| Diagnostic Radiology | 1,131 |
| Mental Health Counselors | 1,052 |
| Optometrist | 1,017 |
| Obstetrics/gynecology | 941 |
| Mass Immunization Roster Billers | 938 |
| Clinical psychologist | 919 |
| Psychiatry | 889 |
| Hospitalist | 794 |
| Cardiology | 687 |
| General surgery | 648 |
| Orthopedic surgery | 648 |
| Podiatry | 601 |
| Neurology | 562 |
| Ophthalmology | 507 |
| Occupational therapist (private practice) | 479 |
| Gastroenterology | 472 |
| Ambulance Service Supplier, e.g., private ambulance companies, funeral homes | 402 |
| Pathology | 390 |
| Pulmonary disease | 380 |
| Physical medicine and rehabilitation | 349 |
| Dermatology | 325 |
| Nephrology | 300 |
| Urology | 282 |
| Audiologist (billing independently) | 277 |
| Otolaryngology | 273 |
| Hematology/oncology | 273 |
| Infectious disease | 235 |
| Pediatric medicine | 215 |
| Endocrinology | 198 |
| Critical care (intensivists) | 197 |
| Radiation oncology | 194 |
| Speech / language pathology | 177 |
| Neurosurgery | 174 |
| Rheumatology | 168 |
| Registered Dietician/Nutrition Professional | 161 |
| Certified nurse midwife | 155 |
| Centralized Flu | 143 |
| Vascular surgery | 143 |
| Ambulatory Surgical Center | 141 |
| Plastic and reconstructive surgery | 134 |
| Medical oncology | 133 |
| Interventional Cardiology | 125 |
| Thoracic surgery | 95 |
| Pharmacy | 94 |
| Sports Medicine | 89 |
| Allergy/immunology | 89 |
| Interventional radiology | 88 |
| Cardiac Electrophysiology | 81 |
| Geriatric medicine | 69 |
| Oral surgery (dentists only) | 66 |
| Pain Management | 64 |
| Colorectal surgery (formerly proctology) | 61 |
| General practice | 58 |
| Hospice and Palliative Care | 57 |
| Marriage and Family Therapist | 56 |
| Advanced Heart Failure and Transplant Cardiology | 51 |
| Hematology | 46 |
| Cardiac surgery | 43 |
| Opioid Treatment Program | 41 |
| Independent Diagnostic Testing Facility (IDTF) | 39 |
| Hand surgery | 39 |
| Gynecologist/oncologist | 33 |
| Sleep Medicine | 31 |
| Clinical Laboratory (Billing Independently) | 29 |
| Maxillofacial surgery | 28 |
| Surgical oncology | 27 |
| Certified clinical nurse specialist | 23 |
| Psychologist (billing independently) | 21 |
| Interventional Pain Management (IPM) | 21 |
| Micrographic Dermatologic Surgery | 20 |
| Osteopathic manipulative therapy | 17 |
| Nuclear medicine | 17 |
| Addiction medicine | 14 |
| Hematopoietic Cell Transplantation and Cellular Therapy | 14 |
| Dentist | 14 |
| General Psychiatry | 12 |
| Epileptologists | 6 |
| Medicare Diabetes Preventive Program | 6 |
| Home Infusion Therapy Services | 5 |
| Portable X-Ray Supplier (Billing Independently) | 5 |
| Neuropsychiatry | 4 |
| Adult Congenital Heart Disease | 3 |
| Single or Multispecialty Clinic or Group Practice | 3 |
| Undersea and Hyperbaric Medicine | 3 |
| All other suppliers, e.g., Drug Stores | 3 |
| Preventive medicine | 2 |
| Medical Genetics and Genomics | 2 |
| Unknown Provider | 1 |
| Peripheral vascular disease | 1 |
| Oral and Maxillofacial Pathology | 1 |
| Medical Toxicology | 1 |