| Nurse practitioner | 9,683 |
| Physician assistant | 8,421 |
| Family practice | 4,301 |
| Internal medicine | 4,271 |
| Physical therapist (private practice) | 3,782 |
| Certified Registered Nurse Anesthetist (CRNA) | 3,569 |
| Emergency medicine | 2,255 |
| Licensed clinical social worker | 1,967 |
| Chiropractic | 1,857 |
| Anesthesiology | 1,841 |
| Diagnostic Radiology | 1,701 |
| Mental Health Counselors | 1,647 |
| Optometrist | 1,582 |
| Clinical psychologist | 1,449 |
| Mass Immunization Roster Billers | 1,433 |
| Obstetrics/gynecology | 1,419 |
| Psychiatry | 1,390 |
| Hospitalist | 1,256 |
| Cardiology | 1,043 |
| General surgery | 1,039 |
| Orthopedic surgery | 955 |
| Podiatry | 916 |
| Neurology | 848 |
| Ophthalmology | 794 |
| Gastroenterology | 758 |
| Occupational therapist (private practice) | 741 |
| Ambulance Service Supplier, e.g., private ambulance companies, funeral homes | 616 |
| Pathology | 582 |
| Pulmonary disease | 580 |
| Dermatology | 527 |
| Physical medicine and rehabilitation | 522 |
| Nephrology | 455 |
| Audiologist (billing independently) | 431 |
| Urology | 422 |
| Hematology/oncology | 421 |
| Otolaryngology | 410 |
| Pediatric medicine | 358 |
| Infectious disease | 330 |
| Endocrinology | 299 |
| Critical care (intensivists) | 289 |
| Radiation oncology | 281 |
| Neurosurgery | 264 |
| Registered Dietician/Nutrition Professional | 263 |
| Rheumatology | 260 |
| Speech / language pathology | 256 |
| Ambulatory Surgical Center | 228 |
| Centralized Flu | 225 |
| Certified nurse midwife | 220 |
| Plastic and reconstructive surgery | 211 |
| Vascular surgery | 210 |
| Medical oncology | 201 |
| Interventional Cardiology | 194 |
| Thoracic surgery | 157 |
| Pharmacy | 145 |
| Allergy/immunology | 139 |
| Cardiac Electrophysiology | 133 |
| Interventional radiology | 131 |
| Sports Medicine | 131 |
| Oral surgery (dentists only) | 119 |
| Pain Management | 110 |
| Hospice and Palliative Care | 107 |
| Marriage and Family Therapist | 101 |
| Geriatric medicine | 98 |
| Colorectal surgery (formerly proctology) | 97 |
| General practice | 88 |
| Advanced Heart Failure and Transplant Cardiology | 71 |
| Hematology | 68 |
| Hand surgery | 67 |
| Opioid Treatment Program | 62 |
| Cardiac surgery | 60 |
| Gynecologist/oncologist | 52 |
| Maxillofacial surgery | 52 |
| Independent Diagnostic Testing Facility (IDTF) | 49 |
| Surgical oncology | 48 |
| Sleep Medicine | 44 |
| Clinical Laboratory (Billing Independently) | 43 |
| Interventional Pain Management (IPM) | 31 |
| Psychologist (billing independently) | 29 |
| Certified clinical nurse specialist | 28 |
| Nuclear medicine | 26 |
| Micrographic Dermatologic Surgery | 26 |
| Hematopoietic Cell Transplantation and Cellular Therapy | 24 |
| Osteopathic manipulative therapy | 23 |
| Addiction medicine | 22 |
| Dentist | 19 |
| General Psychiatry | 14 |
| Epileptologists | 12 |
| Neuropsychiatry | 9 |
| Portable X-Ray Supplier (Billing Independently) | 8 |
| Home Infusion Therapy Services | 7 |
| Preventive medicine | 7 |
| Medicare Diabetes Preventive Program | 6 |
| Single or Multispecialty Clinic or Group Practice | 5 |
| Adult Congenital Heart Disease | 4 |
| Medical Genetics and Genomics | 4 |
| Undersea and Hyperbaric Medicine | 3 |
| All other suppliers, e.g., Drug Stores | 3 |
| Medical Toxicology | 2 |
| Unknown Provider | 1 |
| Peripheral vascular disease | 1 |
| Oral and Maxillofacial Pathology | 1 |
| Orofacial Pain | 1 |
| None | 1 |
| Anesthesiologist Assistant | 1 |