John K. Corless, MD
Specialist
- Medicare participating
At a glance
- Years since graduation
- 49
- In the NPI registry since
- 2005
- Medicare patients seen, 2024
- 60
The NPI date is when this clinician registered for a National Provider Identifier, the billing number used on health claims. It is not a license, graduation or board-certification date. NPIs were first issued in May 2005 and became required on claims in 2007–2008, so an early date usually means the clinician was already in practice before then. What an NPI is
Education and training
- 2005Registered with an NPI (national billing number; not a license date) — NPIs began in 2005, so practice likely started earlier
Medicare’s Care Compare data doesn’t list this clinician’s medical school. Undergraduate school, residency, fellowship, licensing exams and board certification aren’t in public federal data. Board certification can be confirmed with the certifying board (ABMS member boards for MDs, AOA boards for DOs).
Specialties and state licenses
-
Specialist primary
SC license 8734
As reported to the NPI registry. To confirm a license is current, check the state medical board.
Where they work
Medical groups
- University Medical Associates of the Medical University of South Carol (1,668 clinicians)
Hospitals this clinician lists with Medicare, and groups they bill Medicare through (Care Compare). Affiliation doesn’t mean they see patients at every location.
Medicare patients and services
- Medicare patients, 2024
- 60
- Services billed
- 111
- Patients’ average age
- 70
| Service | Times | Patients |
|---|---|---|
| Biopsy of esophagus, stomach, and/or upper small bowel using a flexible endoscope | 44 | 44 |
| Biopsy of large bowel using a flexible endoscope | 41 | 41 |
| Removal of polyps or growths of large bowel using an endoscope with mechanical snare | 22 | 22 |
| Injection beneath lining of large bowel using a flexible endoscope | 16 | 16 |
| Dilation of esophagus | 11 | 11 |
Medicare fee-for-service only. CMS leaves out services billed for fewer than 11 patients. These figures describe a practice’s Medicare work; they aren’t a measure of quality.
Medicare prescriptions
| Drug | Prescriptions |
|---|---|
| Gavilyte-G (peg3350/sod sulf,bicarb,cl/kcl) Other prescribers in Charleston, SC | 37 |
| Peg-3350 And Electrolytes (peg3350/sod sulf,bicarb,cl/kcl) Other prescribers in Charleston, SC | 21 |
Prescriptions filled under Medicare Part D, including refills. CMS leaves out drugs prescribed fewer than 11 times.
Payments from drug and device companies
In 2025, 1 companies reported 1 payments worth $85.20 in total to this clinician.
| Celltrion USA Inc. | $85.20 |
|---|
| Food and Beverage | $85.20 |
|---|
From CMS Open Payments. A payment is not evidence of wrongdoing; many are for consulting, teaching or meals. Clinicians can review and dispute their records with CMS.