ICD-10

The ICD-10-CM code set is maintained by the National Center for Health Statistics (NCHS) of the Centers for Disease Control and Prevention (CDC) for use in the United States.  It is based on ICD-10, which was developed by the World Health Organization (WHO) and is used internationally.  The ICD-10-PCS code set is maintained by the Centers for Medicare & Medicaid Services (CMS).  The final rule does not change the standard for outpatient procedure coding--Current Procedural Terminology (CPT) codes, maintained by the American Medical Association.

ICD-10 Transition Deadline
Comparison of ICD-9 to ICD-10
Tools to Assist the Transition
Additional Resources

ICD-10 Transition Deadline

The transition to ICD-10 is occurring because ICD-9 is able to produce only limited data about patients’ medical conditions and hospital inpatient procedures.  The structure of ICD-9 limits the number of new codes that can be created, and many ICD-9 categories are full.  ICD-9 is 30 years old, uses outdated terminology, and is inconsistent with current medical practice.  Transitioning to ICD-10 will provide more specific coding and more clinical information, which will result in improved ability to measure health care services; increased sensitivity when refining grouping and reimbursement methodologies; more meaningful comparison of morbidity, mortality, and other outcomes data; enhanced ability to conduct public health surveillance; and less need to include supporting documentation with claims. 

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Comparison of ICD-9 to ICD-10

Coding under ICD-10 is more specific and substantially different from ICD-9 coding.  There is a seven-fold increase in the number of ICD-10 diagnosis and procedure codes compared to ICD-9.  In the 2009 versions, the number of available codes is as follows:

A simple crosswalk between ICD-9 and ICD-10 is not sufficient to translate the one-to-many relationships between ICD-9 and ICD-10.  In some cases, a single ICD-9 code could be represented by multiple ICD-10 codes and for other conditions, a single ICD-10 code may require multiple ICD-9 codes.  In addition, some ICD-10 codes have no predecessor ICD-9 codes.  Examples follow.

One ICD-9-CM diagnosis code corresponds to too many possible ICD-10-CM codes:

A cluster of ICD-9-CM diagnosis codes is required to describe one ICD-10-CM code:

One ICD-9-CM procedure code corresponds to multiple possible ICD-10-PCS codes:

A cluster of ICD-9-CM procedure codes is required to describe one ICD-10-PCS code:

A cluster of ICD-10-PCS codes is required to describe one ICD-9-CM procedure code:

A few ICD-10-CM codes have no predecessor ICD-9-CM codes:

• T500x6A Underdosing of mineralocorticoids and their antagonists, initial encounter
• T501x6A Underdosing of loop [high-ceiling] diuretics, initial encounter
• T502x6A Underdosing of carbonic-anhydrase inhibitors, benzothiadiazides and other diuretics, initial encounter
• T503x6A Underdosing of electrolytic, caloric and water-balance agents, initial encounter
• T504x6A Underdosing of drugs affecting uric acid metabolism, initial encounter

Tools to Assist the Transition

General Equivalence Mappings (GEMs)

CMS and the CDC created the GEMs to convert data coded using ICD-9 to ICD-10 and vice versa.  The GEMs have been used to:

• Translate ICD-9 codes in the official coding guidelines in preparation for production of the official ICD-10 coding guidelines. 
• Convert version 26.0 of Medicare Severity Diagnosis-Related Groups from an ICD-9-CM-based application to an ICD-10-CM/PCS-based application;
• Convert the Medicare Code Editor to a native ICD-10-CM/PCS-based application
• Produce an ICD-10-CM/PCS to ICD-9-CM crosswalk for reimbursement called the ICD-10 Reimbursement Mappings.
  

It’s not clear whether 3M converted their All Patient Refined Grouper, Ambulatory Payment Categories, Potentially Preventable Conditions, and Potentially Preventable Readmissions software to an ICD-10-CM/PCS-based application.

Reimbursement Mappings

The ICD-10 reimbursement mappings were developed by CMS in response to non-Medicare payor requests for a standard one-to-one reimbursement crosswalk.  All ICD-10-CM/PCS codes are in the Reimbursement Mappings; however, all ICD-9-CM codes are not in the Reimbursement Mappings. Where an ICD-10-CM/PCS code translates to more than one ICD-9-CM code, a single choice was made to create a functioning crosswalk.  As described by the examples above, a simple one-to-one crosswalk is inadequate to accurately translate ICD-10 coded data to ICD-9 coded data.  CMS is not using the ICD-10 Reimbursement Mappings for any purpose.  They are converting their systems and applications to accept ICD-10-CM/PCS codes directly.

It is unclear whether the major Maryland payors, other than Medicare, plan to convert their systems to directly accept ICD-10 codes.

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Additional Resources

CMS Web site
https://www.cms.gov/ICD10/

American Hospital Association (AHA) Web site http://www.ahacentraloffice.org/ahacentraloffice/shtml/ICD10overview.shtml

Health Information and Management Systems Society (HIMSS) Web site http://www.himss.org/ASP/topics_FocusDynamic.asp?faid=220

American Health Information Management Association (AHIMA) Web site http://www.ahima.org/icd10/

Basic Information about the ICD-10 Code Sets (ICD-10-CM Diagnoses and ICD-10-PCS Procedures) and Federal Regulatory Requirements
National Center for Health Statistics
CMS

Basic Information on Coding and Coder Training
AHIMA (institutional coding)
AAPC (professional coding)

Implementation Guidance
WEDI - ICD-10 white papers, workgroups
NCHICA ICD-10 Workgroup
HIMSS ICD-10 Playbook
American Hospital Association
American Medical Association
MGMA

Major Supporting Vendors
WEDI ICD-10 Vendor Directory
3M
Ingenix
Trizetto

ICD-10 News
ICD-10 Watch

CMS MLN Matters
MLN - ICD-10 Coding Dates 



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