| Nurse practitioner | 6,408 |
| Physical therapist (private practice) | 2,850 |
| Physician assistant | 2,670 |
| Internal medicine | 2,541 |
| Family practice | 2,341 |
| Licensed clinical social worker | 1,779 |
| Emergency medicine | 1,344 |
| Chiropractic | 1,308 |
| Certified Registered Nurse Anesthetist (CRNA) | 1,296 |
| Anesthesiology | 1,132 |
| Optometrist | 968 |
| Mental Health Counselors | 931 |
| Clinical psychologist | 906 |
| Obstetrics/gynecology | 860 |
| Diagnostic Radiology | 835 |
| Hospitalist | 764 |
| Psychiatry | 635 |
| Podiatry | 552 |
| Mass Immunization Roster Billers | 549 |
| General surgery | 527 |
| Orthopedic surgery | 506 |
| Occupational therapist (private practice) | 497 |
| Neurology | 493 |
| Cardiology | 482 |
| Gastroenterology | 426 |
| Ophthalmology | 417 |
| Pathology | 356 |
| Ambulance Service Supplier, e.g., private ambulance companies, funeral homes | 354 |
| Centralized Flu | 346 |
| Hematology/oncology | 321 |
| Pulmonary disease | 313 |
| Dermatology | 303 |
| Nephrology | 286 |
| Urology | 243 |
| Audiologist (billing independently) | 242 |
| Otolaryngology | 232 |
| Physical medicine and rehabilitation | 229 |
| Speech / language pathology | 225 |
| Pediatric medicine | 202 |
| Infectious disease | 187 |
| Interventional Cardiology | 177 |
| Endocrinology | 171 |
| Registered Dietician/Nutrition Professional | 153 |
| Critical care (intensivists) | 148 |
| Rheumatology | 140 |
| Radiation oncology | 130 |
| Neurosurgery | 120 |
| Clinical Laboratory (Billing Independently) | 113 |
| Certified nurse midwife | 108 |
| Allergy/immunology | 103 |
| Plastic and reconstructive surgery | 103 |
| Vascular surgery | 97 |
| Ambulatory Surgical Center | 93 |
| Cardiac Electrophysiology | 79 |
| Certified clinical nurse specialist | 73 |
| Sports Medicine | 65 |
| Interventional radiology | 65 |
| Thoracic surgery | 64 |
| Independent Diagnostic Testing Facility (IDTF) | 60 |
| General practice | 60 |
| Medical oncology | 58 |
| Hand surgery | 54 |
| Geriatric medicine | 49 |
| Pain Management | 48 |
| Hospice and Palliative Care | 45 |
| Colorectal surgery (formerly proctology) | 43 |
| Marriage and Family Therapist | 41 |
| Pharmacy | 40 |
| Sleep Medicine | 36 |
| Opioid Treatment Program | 36 |
| Surgical oncology | 34 |
| Advanced Heart Failure and Transplant Cardiology | 34 |
| Interventional Pain Management (IPM) | 33 |
| Cardiac surgery | 31 |
| Gynecologist/oncologist | 29 |
| Maxillofacial surgery | 25 |
| Oral surgery (dentists only) | 23 |
| Hematology | 12 |
| Neuropsychiatry | 12 |
| Hematopoietic Cell Transplantation and Cellular Therapy | 10 |
| Dentist | 10 |
| Single or Multispecialty Clinic or Group Practice | 10 |
| Portable X-Ray Supplier (Billing Independently) | 9 |
| Micrographic Dermatologic Surgery | 8 |
| Epileptologists | 8 |
| Preventive medicine | 8 |
| Addiction medicine | 7 |
| Osteopathic manipulative therapy | 6 |
| Anesthesiologist Assistant | 5 |
| Nuclear medicine | 5 |
| All other suppliers, e.g., Drug Stores | 4 |
| Medical Genetics and Genomics | 3 |
| Undersea and Hyperbaric Medicine | 3 |
| Adult Congenital Heart Disease | 3 |
| Unknown physician specialty | 2 |
| Peripheral vascular disease | 1 |
| Slide Preparation Facilities | 1 |
| Prosthodontics | 1 |
| Medicare Diabetes Preventive Program | 1 |
| General Psychiatry | 1 |
| Intensive Cardiac Rehabilitation | 1 |
| Home Infusion Therapy Services | 1 |