About the author
Who writes Master ICD-10-CM, what the site is for, and what it deliberately does not try to replace.
Master ICD-10-CM is written and maintained by Dr. Santosh Kumar Guptha, CCS, CCS-P, CPC, COC, CIC, CPC-P, CRC, CPMA, CDIP, CPCO, CEMC, CRHC, CPB and CPMB® — a first-generation AHIMA-Approved ICD-10-CM/PCS and ICD-11 trainer, and founder of MEDESUN® Medical Coding Academy.
Background#
| Experience | 22+ years in medical coding, coding audit, clinical documentation integrity and revenue cycle management, including nearly seven years in the United States working directly with physicians in Florida, New Jersey, New York, Texas and California. |
|---|---|
| Credentials | 43 certifications across coding, auditing, compliance and billing, beginning with the CPC in 2004; also HIMAA ICD-10-AM Level 1 and CPHM-ISB; more than 800 continuing education units. |
| Trainer status | First-generation AHIMA-Approved ICD-10-CM/PCS Trainer and AHIMA-Approved ICD-11 Trainer. |
| Volume | Oversight of the coding of approximately one million patient records across inpatient, outpatient, professional-fee and risk-adjustment work. |
| Teaching | More than 30,000 coding professionals trained worldwide, across specialty coding, auditing, CDI and credential preparation. |
Why this site exists#
Coders rarely fail because they cannot find a code. They fail because a guideline was read once, years ago, and then applied from memory — and the guideline has since been revised, or was never fully read in the first place. The official guidelines are authoritative but they are written as a legal instrument, in long numbered paragraphs, in a PDF that nobody reads at the desk.
This site is an attempt to close that gap. The wording of the FY 2027 guidelines is kept faithfully; what is added is structure — tables instead of paragraphs, sequencing diagrams, the query that should have been raised, the audit finding that follows when it was not, and questions that test whether the rule was actually understood.
Other work#
- MEDESUN® Medical Coding Academy — coding, auditing, CDI and credential preparation training. medesunglobal.com
- PMBAUSA LLC — United States facing credentialing and professional development. pmbausa.com
- Hinfoma Global — HIM and medical coding services and consulting: coding audit, compliance, CDI, EHR and revenue optimisation. hinfoma.com
- CodersGrade® — internship and practice platform for new coders.
Corrections and feedback#
Guidelines are revised every year and errors in restating them are possible. If a page here disagrees with the official FY 2027 text, the official text governs — and the page should be corrected. Corrections are welcome through MEDESUN Medical Coding Academy.
Primary sources#
- ICD-10-CM Official Guidelines for Coding and Reporting, FY 2027CMS — the source document for every page on this site (effective 1 Oct 2026)
- NCHS ICD-10-CM files — Tabular List, Index, POA exempt listOfficial code files, addenda and the list of codes exempt from POA reporting
- ICD-10 Coordination and Maintenance CommitteeWhere code proposals are debated; agendas, summaries and meeting materials
- CMS ICD-10 homeCode sets, transition guidance and Medicare coding policy
- AHA Coding ClinicOfficial coding advice from the AHA Central Office — subscription required
- HHS OIG Work PlanActive audit topics — useful for prioritising internal coding audits
- MEDESUN Medical Coding AcademyTraining, credential preparation and audit services by the author