# What Is Medical Coding? ICD-10 vs. CPT/HCPCS Canonical: https://www.flobotics.io/blog/medical-coding-explanation Author: Jędrzej Szymula Published: 2026-04-07 Updated: 2026-09-14 --- [Home](https://www.flobotics.io/)/[Articles](https://www.flobotics.io/blog)/What Is Medical Coding? ICD-10 vs. CPT/HCPCS [Healthcare](https://www.flobotics.io/blog?category=healthcare)[RCM](https://www.flobotics.io/blog?category=rcm) # What Is Medical Coding? ICD-10 vs. CPT/HCPCS [Jędrzej SzymulaContent Manager ](https://www.flobotics.io/our-editorial-team#jedrzej) Published April 07, 2026Updated September 14, 2026 On this page - [Medical Coding](#medical-coding) - [ICD-10 vs. CPT/HCPCS — What's the Difference?](#icd-10-vs-cpt-hcpcs-what-s-the-difference) - [Why Coding Accuracy Drives Clean Claims](#why-coding-accuracy-drives-clean-claims) - [Who Codes, and How It Connects to RCM](#who-codes-and-how-it-connects-to-rcm) Book a callWant to talk about it? 30 minutes with someone who builds automations, not a sales script. [Talk to us →](https://www.flobotics.io/contact) Share [](#)[](#) ## Medical Coding The translation of clinical diagnoses (ICD-10) and procedures (CPT/HCPCS) into standardized alphanumeric codes for claims processing. ## ICD-10 vs. CPT/HCPCS — What's the Difference? Medical coding relies on two distinct code sets that answer different questions on a claim. ICD-10-CM codes describe why a patient was seen — the diagnosis or reason for the encounter. CPT and HCPCS codes describe what was done — the procedure, service, or supply provided. - ICD-10-CM (diagnosis codes): Maintained by CMS together with the CDC's National Center for Health Statistics, these alphanumeric codes classify diagnoses and reasons for visits across every care setting. As CMS notes on its ICD-10 codes page, ["ICD-10 applies to all parties covered by the Health Insurance Portability and Accountability Act (HIPAA), not just providers who bill Medicare or Medicaid"](https://www.cms.gov/medicare/coding-billing/icd-10-codes). - CPT (procedure codes): Owned and updated by the American Medical Association, the [AMA's CPT code set basics and resources](https://www.ama-assn.org/practice-management/cpt/cpt-code-set-basics-and-resources) guide describes it as a listing of descriptive terms and five-digit codes for reporting medical services and procedures performed by physicians and other qualified health care professionals. More than 11,000 codes make up the set today. - HCPCS Level II codes: Also maintained by CMS, these cover supplies, durable medical equipment, and services — like ambulance transport or certain drugs — that fall outside the CPT code set, and are used heavily in Medicare and Medicaid billing. ## Why Coding Accuracy Drives Clean Claims A claim only pays cleanly when the diagnosis code, procedure code, and any required modifiers line up with what the payer's adjudication system expects. Mismatched codes, missing modifiers, or stale code sets are a common cause of "technical" denials — claims rejected on formatting grounds before a payer ever evaluates the clinical picture. Flobotics's own [claims management automation case study for Gentem Health](https://www.flobotics.io/case-studies/98-reduction-in-manual-claim-prep-claims-management-automation) shows this dynamic directly: standardizing how CPT/ICD codes, modifiers, and provider identifiers were captured and validated before submission lifted the clean claim rate from roughly 80% to 95%, cutting the coding-driven denials that have nothing to do with medical necessity. A similar pattern appears in Flobotics's [document-to-claim automation case study with SuperBill](https://www.flobotics.io/case-studies/70-faster-claim-turnaround-time-ctt-claim-management-automation), where an AI agent structured CPT/ICD codes and modifiers extracted from unstructured superbills, cutting claim turnaround time by about 70% and reducing document-related error rates by roughly 35%. ## Who Codes, and How It Connects to RCM Medical coding is typically performed by certified coders — often credentialed through organizations like AAPC or AHIMA — working from clinical documentation, or increasingly with computer-assisted coding tools that suggest codes for human review. Once codes are assigned, they flow directly into claims processing, eligibility checks, and, when something doesn't match, denials management — making coding accuracy one of the earliest and highest-leverage points to get right in the revenue cycle. Let’s talk! It’s a 30-minute call. Within the first 15, we’ll know if automation works for you. [Book a call →](https://tidycal.com/team/flobotics/flobotics-intro-call-w) ## FAQ: What's the difference between CPT, ICD-10, and HCPCS codes? ICD-10 codes the diagnosis, CPT codes the procedure performed, and HCPCS Level II codes supplies, equipment, and services that CPT doesn't cover. Is medical billing the same as medical coding? No. A coder translates clinical documentation into diagnosis and procedure codes. A biller uses those codes to build and submit the claim, then manages everything that happens to it afterward. Written byJędrzej Szymula Content Manager . [More from Jędrzej](https://www.flobotics.io/our-editorial-team#jedrzej) Talk to us ## Show us the process your team is tired of doing manually. Let Karl, our CTO, take a look. It’s 30 minutes with the person who designs the automations, not a sales script. [Book a call with Karl →](https://tidycal.com/team/flobotics/flobotics-intro-call-w)[Send us a message](https://www.flobotics.io/contact) 30-minute callKarl MielnickiCo-founder, CTO Walk me through the process your team does by hand. I’ll tell you whether it’s worth automating and how I’d approach it. Karl Keep reading ## More insight The latest industry news, interviews, technologies, and resources. [ HealthcareRCM ### Charge Capture: What It Is and How It Works in RCM What is charge capture? How converting clinical services into billable charges kicks off the revenue cycle, and why missed charges are lost revenue. Karl MielnickiJune 03, 2026 ](https://www.flobotics.io/blog/charge-capture-explanation)[ HealthcareRCM ### Clinical Documentation Integrity (CDI): Why It Matters Clinical Documentation Integrity (CDI), explained: how documentation gaps drive undercoding and silent revenue leakage. Karl MielnickiMarch 03, 2026 ](https://www.flobotics.io/blog/clinical-documentation-integrity-cdi-explanation)[ HealthcareRCM ### What Is Claim Scrubbing? What Gets Checked Before Submission Claim scrubbing, explained: how automated pre-submission checks catch errors that cost $25-$44 per claim to fix after denial. Krzysztof SzwedMarch 24, 2026 ](https://www.flobotics.io/blog/claim-scrubbing-explanation) [All articles →](https://www.flobotics.io/blog)