Coding rules are divided into several categories. In the United States these consist of ICD-‐9-‐CM / ICD-‐10 diagnosis and procedural coding. Generally these are relegated to inpatient claims and when
appropriately applied and sequenced result in a DRG type methodology when grouped. Alternatively, the U.S. differs from any other country in the use of AMA copyrighted CPT (Common Procedural Coding) and HCPCS Level II codes to represent procedures and supplies in the outpatient setting. Suppliers such as physicians and non-‐physician practitioners utilize CPT / HCPCS coding for both inpatient and outpatient coding procedures.
ICD-‐9 CODING RULES
The International Classification of Diseases (version 9 and 10) are managed by the Centers for Disease Control and Prevention (CDC) within the U.S. The International Classification
Of Diseases, Clinical Modification, currently in its ninth revision (ICD-‐9-‐CM), is used
to describe and report the illnesses, conditions, and injuries of patients who require medical services. There are specific guidelines to be followed which are published on their website at:
http://www.cdc.gov/nchs/icd/icd9cm.htm. Selection of the version required can be done by reviewing items on the left side of the webpage.
For each version of ICD there are specific guidelines on their use. The auditor must follow these
guidelines in order to ensure that appropriate and accurate coding results. The complete guidelines can be found at: http://www.cdc.gov/nchs/icd/icd9cm_addenda_guidelines.htm#guidelines
When using ICD-‐9-‐CM, ICD-‐10, the auditor must use the guidelines as specified by the payer. Most payers within the U.S. are on ICD-‐9-‐CM with a migration toward ICD-‐10. While other countries such as Australia, Germany and U.K. have been on ICD-‐10 for many years. Additionally, commercial, managed care and Medicaid utilize either ICD-‐9-‐CM of potentially ICD-‐10 for diagnosis and procedure coding.
Medicare does not utilize ICD-‐9-‐CM procedural coding for outpatient services but instead uses CPT/HCPCS Level II coding for procedures. However, Medicare and all other payers do use ICD-‐9-‐CM procedural coding for inpatient services. The auditor must understand the payer requirements for reporting procedures.
ICD-‐10 CODING OVERVIEW
ICD-‐10 is very similar in coding conventions to ICD-‐9 but much more expansive and consists of a nomenclature not previously seen in the U.S. ICD-‐10 has been used in many other countries for years and now being adapted from the World Health Organisation (WHO) to U.S. standards in ICD-‐10-‐CM. CMS training documents provide some overview of the extent of the changes. For example there are 14,025 ICD-‐9-‐CM codes which translate into approximately 68,000 ICD-‐CM codes and are much more specific than ICD-‐9-‐CM. In terms of procedure codes there are 3,824 ICD-‐9-‐PCS codes that will translate to over 72,500 ICD-‐10-‐PCS codes. As auditors knowledge of these codes will be essential as you move forward in your area of expertise. No matter if you are an external, independent or internal auditor ICD-‐ 10 will be a required knowledge item.
According to the CMS fact sheet ICD-‐10:
“ICD-‐10-‐CM/PCS (International Classification of Diseases, 10th Edition, Clinical Modification/Procedure Coding System) consists of two parts:
• ICD-‐10-‐CM for diagnosis coding
• ICD-‐10-‐PCS for inpatient procedure coding
ICD-‐10-‐CM is for use in all U.S. health care settings. Diagnosis coding under ICD-‐10-‐CM uses 3 to 7 digits instead of the 3 to 5 digits used with ICD-‐9-‐CM, but the format of the code sets is similar.
ICD-‐10-‐PCS is for use in U.S. inpatient hospital settings only. ICD-‐10-‐PCS uses 7 alphanumeric digits instead of the 3 or 4 numeric digits used under ICD-‐9-‐CM procedure coding. Coding under ICD-‐10-‐PCS is much more specific and substantially different from ICD-‐9-‐CM procedure coding.”51
Coding conventions for ICD-‐9 and ICD-‐10 remain the same that the code assigned must be assigned to the highest specificity possible. The following is an excerpt from the ICD-‐10 coding guidelines
“ICD-‐10-‐CM diagnosis codes are composed of codes with 3, 4, 5, 6 or 7 characters. Codes with three characters are included in ICD-‐10-‐CM as the heading of a category of codes that may be further subdivided by the use of fourth and/or fifth characters and/or sixth characters, which provide greater detail.
A three-‐character code is to be used only if it is not further subdivided. A code is invalid if it has not been coded to the full number of characters required for that code, including the 7th character, if
applicable.”52
An example of an ICD-‐10 code is as follows: CD-‐10 Code Structure:
• Characters 1-‐3 – Category
• Characters 4-‐6 – Etiology, anatomic site, severity, or other clinical detail • Characters 7 – Extension
This is detailed in the example below from the ICD-‐10-‐CM 2012 GEM table at www.cms.gov/ICD10
While the U.S. is adapting and modifying the ICD-‐10 version created by the World Health Organisation, the training offered by WHO is still very valuable. A full module training system can be found at: http://apps.who.int/classifications/apps/icd/icd10training/
RESOURCE GUIDE AND CROSS REFERENCE
Resource Guide
• HIPAA and ICD-‐10 Implementation
• https://www.resourcenter.net/images/AAMAS/ResourceLibrary/Know
ledgeRecap-‐ICD-‐10-‐Summer2010.pdf
Cross Reference:
BOK 02: Assign / Validate ICD-‐9-‐CM Codes 52 https://www.cms.gov/ICD10/Downloads/2012_ICD10_Guidelines.pdf
OUTPATIENT PROCEDURAL CODING: CPT & HCPCS LEVEL II
Current Procedural Terminology (CPT) is a “set of codes, descriptions, guidelines intended to describe procedures and services performed by physicians and other healthcare providers. Each procedure or service is identified with a five-‐digit code.”53
CPT coding guidelines state the following. “Select the name of the procedure or service that accurately identifies the service performed. Do not select a CPT code that merely approximates the service provided. If no such specific code exists, then report the service using the appropriate unlisted procedure or service code. ... Any service or procedure should be adequately documented in the medical record... Instructions typically included as parenthetical notes, which selected codes indicate that a code should not be reported with another code or codes. These instructions are intended to prevent errors of significant probability and are not all inclusive.”54
Located within the introduction and the section notes within CPT are the coding guidelines for CPT. Per Medicare, when assigning codes for procedures performed on Medicare beneficiaries the coder/ auditor should follow “the intent of CPT.”
HCPCS Level II codes are the sole domain of the U.S. Government. However, coding guidance is provided by AHIMA. https://www.cms.gov/MedHCPCSGenInfo/20_HCPCS_Coding_Questions.asp
OTHER FORMS OF CODING GUIDANCE
Beyond ICD, CPT, HCPCS coding regulatory bodies and payers provide their own additional coding guidance. Examples of this include Correct Coding Initiatives (CCI), Transmittals and coding guidance.
53 AMA CPT 2011, American Medical Association, p.x. Introduction 54 AMA CPT 2011, American Medical Association, p.x Introduction
NCCI:
“The CMS developed the National Correct Coding Initiative (NCCI) to promote national correct coding methodologies and to control improper coding leading to inappropriate payment in Part B claims. The CMS developed its coding policies based on coding conventions defined in the American Medical Association's CPT manual, national and local policies and edits, coding guidelines developed by national societies, analysis of standard medical and surgical practices, and a review of current coding practices. The CMS annually updates the National Correct Coding Initiative Coding Policy Manual for Medicare Services (Coding Policy Manual). Carriers and FIs should utilize the Coding Policy Manual as a general reference tool that explains the rationale for NCCI edits.
Carriers implemented NCCI edits within their claim processing systems for dates of service on or after January 1, 1996.
A subset of NCCI edits is incorporated into the outpatient code editor (OCE) for OPPS and therapy providers (Skilled nursing facilities (SNFs), comprehensive outpatient rehabilitation facilities (CORFs), outpatient physical therapy and speech-‐language pathology providers (OPTs), and home health agencies (HHAs) billing under TOBs 22X, 23X, 75X, 74X, 34X).
The purpose of the NCCI edits is to prevent improper payment when incorrect code combinations are reported. The NCCI contains two tables of edits. The Column One/Column Two Correct Coding Edits table and the Mutually Exclusive Edits table include code pairs that should not be reported together for a number of reasons explained in the Coding Policy Manual.”55
It is important to see an important change in the way NCCI has functioned since 1996. As of April 1, 2012 the following instructions apply to CMS NCCI for Medicare.
Since 1996 the Medicare NCCI procedure to procedure edits have been assigned to either the Column One/Column Two Correct Coding edit file or the Mutually Exclusive edit file based on the criterion for each edit. The Mutually Exclusive edit file included edits where two procedures could not be performed at the same patient encounter because the two procedures were mutually exclusive based on anatomic, temporal, or gender considerations. All other edits were assigned to the Column One/Column Two Correct Coding edit file. There are important
upcoming changes to these files described below.
In order to simplify the use of NCCI edit files, CMS will consolidate the two edit files into the Column One/Column Two Correct Coding edit file. Separate consolidations will occur for the two practitioner NCCI edit files and the two NCCI edit files used for OCE. This change will occur for practitioner NCCI edits in NCCI version 18.1 scheduled for April 1, 2012. After these changes occur, it will only be necessary to search the Column One/Column Two Correct Coding edit file
for active or previously deleted edits. Effective April 1, 2012, CMS will no longer publish a Mutually Exclusive edit file on its website for either practitioner or outpatient hospital services since all active and deleted edits will appear in the single Column One/Column Two Correct Coding edit file on each website. The edits previously contained in the Mutually Exclusive edit file are NOT being deleted but are being moved to the Column One/Column Two Correct Coding edit file.
Practitioner NCCI -‐ In NCCI version 18.1 for practitioners scheduled for April 1, 2012, all edits in the Mutually Exclusive edit file will be moved to the Column One/Column Two Correct Coding edit file with the same implementation and, if relevant, deletion date as the edits have in the mutually exclusive edit file. These edits are not being deleted from NCCI but are being moved to the Column One/Column Two Correct Coding edit file. The net result will be that the NCCI version 18.1 Column One/Column Two Correct Coding edit file will contain all active NCCI edits and deleted NCCI edits that previously were contained in the Mutually Exclusive and Column One/Column Two Correct Coding edit files. The CMS website will have a single Column One/Column Two Correct Coding edit file for practitioner NCCI.
Outpatient NCCI used in OCE -‐ Effective April 1, 2012 the change will be implemented on the CMS website where a single Column One/Column Two Correct Coding edit file will appear which will contain all active NCCI edits and deleted NCCI edits that previously were contained in the OPPS Mutually Exclusive and Column One/Column Two Correct Coding edit files. These edits are not being deleted from the OCE NCCI files but are being moved to the Column
One/Column Two Correct Coding edit file. 56
Medicaid also utilizes NCCI in the correct coding initiative for that programme. Further information can be found at: http://www.cms.gov/MedicaidNCCICoding/Downloads/NCCIEditDesignManual.pdf
Transmittals – Medicare:
Occasionally, Medicare, the OIG, and/or Medicaid provide additional guidance through the format of a transmittal on a particular coding issue. An example of this is Transmittal A-‐01-‐80 covering the coding guidance for modifier 25 and 27.
Medicare Administrative Contractor Coding Guidance:
In addition to source guidance such as CPT, ICD-‐9, HCPCS and transmittals, the MACs can provide additional coding guidance. This occurs when there is an area of confusion or noted continued errors. Sometimes this is published as an alert other times it is provided in an “Ask the Contractor”
teleconference. The auditor should review these documents if performing Medicare audits within a specific region.
Individual payers also provide coding guidance. Generally, they tend to follow the guidelines as published by ICD-‐9-‐CM, ICD-‐10 and/or CPT/HCPCS however occasionally they provide additional guidance. If a payer auditor is conducting a client audit then this guidance must be followed per the contract with the client. If the contract is silent then Medicare regulations apply.
One example is the Anthem Blue Cross Coding Compliance Program. Further information can be found at:
http://www.anthem.com/provider/noapplication/f1/s0/t0/pw_b132856.pdf?refer=ahpprovider&state= wi
Summary:
In summation, there are different coding guidelines and different regulatory bodies specifying the guidelines. These are based on the type of payer (Federal, State, Commercial Payer) and patient status (inpatient or outpatient). The auditor must review and utilize the correct coding guidance. In some cases, especially the inpatient status proprietary software such as Milliman or Interqual, 3M grouper include the AHA coding clinics documentation. 3M encoders include CPT / HCPCS coding information. No matter what audit is being performed the coding guidance for the type of patient and payer must be strictly adhered to.