| Nurse practitioner | 1,095 |
| Physician assistant | 659 |
| Physical therapist (private practice) | 427 |
| Family practice | 371 |
| Internal medicine | 331 |
| Anesthesiology | 243 |
| Chiropractic | 214 |
| Emergency medicine | 202 |
| Mental Health Counselors | 193 |
| Licensed clinical social worker | 186 |
| Diagnostic Radiology | 178 |
| Clinical psychologist | 146 |
| Obstetrics/gynecology | 132 |
| Hospitalist | 114 |
| Psychiatry | 108 |
| Occupational therapist (private practice) | 107 |
| Mass Immunization Roster Billers | 103 |
| General surgery | 101 |
| Optometrist | 86 |
| Certified Registered Nurse Anesthetist (CRNA) | 85 |
| Orthopedic surgery | 83 |
| Cardiology | 69 |
| Hematology/oncology | 65 |
| Gastroenterology | 63 |
| Dermatology | 63 |
| Neurology | 63 |
| Ophthalmology | 61 |
| Anesthesiologist Assistant | 61 |
| Centralized Flu | 58 |
| Pathology | 52 |
| Pulmonary disease | 48 |
| Podiatry | 48 |
| Nephrology | 44 |
| Physical medicine and rehabilitation | 41 |
| Audiologist (billing independently) | 41 |
| Endocrinology | 39 |
| Urology | 36 |
| Infectious disease | 36 |
| Otolaryngology | 35 |
| Critical care (intensivists) | 35 |
| Ambulance Service Supplier, e.g., private ambulance companies, funeral homes | 31 |
| Speech / language pathology | 30 |
| Radiation oncology | 29 |
| Pediatric medicine | 29 |
| Neurosurgery | 28 |
| Plastic and reconstructive surgery | 24 |
| Registered Dietician/Nutrition Professional | 23 |
| Ambulatory Surgical Center | 21 |
| Marriage and Family Therapist | 17 |
| Interventional Cardiology | 17 |
| Certified nurse midwife | 16 |
| Pharmacy | 15 |
| Surgical oncology | 14 |
| Allergy/immunology | 14 |
| Rheumatology | 13 |
| Interventional radiology | 13 |
| Cardiac Electrophysiology | 12 |
| Vascular surgery | 12 |
| Geriatric medicine | 10 |
| Hospice and Palliative Care | 10 |
| Pain Management | 9 |
| Undersea and Hyperbaric Medicine | 7 |
| Clinical Laboratory (Billing Independently) | 7 |
| Hand surgery | 6 |
| Medical oncology | 6 |
| General practice | 6 |
| Colorectal surgery (formerly proctology) | 6 |
| Interventional Pain Management (IPM) | 5 |
| Independent Diagnostic Testing Facility (IDTF) | 5 |
| Thoracic surgery | 5 |
| Oral surgery (dentists only) | 4 |
| Opioid Treatment Program | 4 |
| Advanced Heart Failure and Transplant Cardiology | 4 |
| Maxillofacial surgery | 4 |
| Single or Multispecialty Clinic or Group Practice | 3 |
| Cardiac surgery | 3 |
| Gynecologist/oncologist | 3 |
| Sleep Medicine | 3 |
| Medicare Diabetes Preventive Program | 2 |
| Portable X-Ray Supplier (Billing Independently) | 2 |
| Sports Medicine | 2 |
| Osteopathic manipulative therapy | 2 |
| Preventive medicine | 1 |
| Hematology | 1 |
| Home Infusion Therapy Services | 1 |
| Addiction medicine | 1 |
| Micrographic Dermatologic Surgery | 1 |
| All other suppliers, e.g., Drug Stores | 1 |
| Nuclear medicine | 1 |
| Epileptologists | 1 |
| Certified clinical nurse specialist | 1 |
| Neuropsychiatry | 1 |
| Medical Genetics and Genomics | 1 |