| Nurse practitioner | 1,739 |
| Internal medicine | 993 |
| Physician assistant | 963 |
| Licensed clinical social worker | 799 |
| Physical therapist (private practice) | 679 |
| Anesthesiology | 458 |
| Psychiatry | 451 |
| Clinical psychologist | 427 |
| Family practice | 388 |
| Diagnostic Radiology | 354 |
| Mental Health Counselors | 302 |
| Certified Registered Nurse Anesthetist (CRNA) | 297 |
| Neurology | 267 |
| Emergency medicine | 266 |
| Obstetrics/gynecology | 249 |
| Optometrist | 241 |
| Cardiology | 198 |
| Chiropractic | 195 |
| Ophthalmology | 184 |
| Orthopedic surgery | 183 |
| Pathology | 181 |
| Dermatology | 171 |
| Gastroenterology | 157 |
| Hospitalist | 155 |
| General surgery | 132 |
| Mass Immunization Roster Billers | 126 |
| Hematology/oncology | 121 |
| Pulmonary disease | 113 |
| Endocrinology | 109 |
| Medical oncology | 105 |
| Pediatric medicine | 104 |
| Otolaryngology | 92 |
| Infectious disease | 85 |
| Physical medicine and rehabilitation | 82 |
| Urology | 77 |
| Audiologist (billing independently) | 76 |
| Podiatry | 70 |
| Occupational therapist (private practice) | 70 |
| Nephrology | 59 |
| Centralized Flu | 57 |
| Rheumatology | 57 |
| Registered Dietician/Nutrition Professional | 53 |
| Critical care (intensivists) | 49 |
| Ambulance Service Supplier, e.g., private ambulance companies, funeral homes | 48 |
| Radiation oncology | 46 |
| Certified clinical nurse specialist | 45 |
| Allergy/immunology | 44 |
| Neurosurgery | 43 |
| Certified nurse midwife | 41 |
| Vascular surgery | 39 |
| Oral surgery (dentists only) | 36 |
| Hospice and Palliative Care | 35 |
| Plastic and reconstructive surgery | 31 |
| Cardiac Electrophysiology | 25 |
| Thoracic surgery | 23 |
| Speech / language pathology | 23 |
| Pharmacy | 20 |
| Hand surgery | 20 |
| Ambulatory Surgical Center | 19 |
| Hematology | 18 |
| Geriatric medicine | 18 |
| Sports Medicine | 18 |
| Interventional Cardiology | 18 |
| Independent Diagnostic Testing Facility (IDTF) | 17 |
| Interventional radiology | 16 |
| Pain Management | 13 |
| Marriage and Family Therapist | 12 |
| Surgical oncology | 11 |
| Advanced Heart Failure and Transplant Cardiology | 11 |
| Colorectal surgery (formerly proctology) | 10 |
| Cardiac surgery | 10 |
| Epileptologists | 9 |
| Gynecologist/oncologist | 9 |
| Dentist | 8 |
| General Psychiatry | 7 |
| Maxillofacial surgery | 6 |
| Medical Genetics and Genomics | 5 |
| Public Health or Welfare Agencies (Federal, State, and local) | 5 |
| General practice | 5 |
| Opioid Treatment Program | 4 |
| Interventional Pain Management (IPM) | 4 |
| Preventive medicine | 4 |
| Single or Multispecialty Clinic or Group Practice | 4 |
| Adult Congenital Heart Disease | 4 |
| Sleep Medicine | 4 |
| Osteopathic manipulative therapy | 3 |
| Nuclear medicine | 3 |
| Clinical Laboratory (Billing Independently) | 3 |
| Micrographic Dermatologic Surgery | 3 |
| Portable X-Ray Supplier (Billing Independently) | 1 |
| Orofacial Pain | 1 |
| Peripheral vascular disease | 1 |
| Home Infusion Therapy Services | 1 |
| Addiction medicine | 1 |