1. Insurance Handbook for the Medical Office
13th edition
Chapter 05
Diagnostic Coding

2. Introduction to Diagnostic Coding
Lesson 5.1
Introduction to Diagnostic Coding
Explain the reasons and importance of coding diagnoses.
Describe the importance of matching the correct diagnostic code to the appropriate procedural code.
Differentiate between primary (first listed), principal, and secondary diagnoses.
Describe how medical necessity is supported by the diagnosis code.
Differentiate between ICD-10-CM and ICD-10-PCS.

3. Introduction to Diagnostic Coding (cont’d)
Lesson 5.1
Introduction to Diagnostic Coding (cont’d)
Discuss the history of diagnostic coding.
Compare the process for locating a code in ICD-9-CM versus ICD-10-CM.
Identify the Alphabetic and Tabular Index of the ICD-10-CM coding manual.
Define and demonstrate an understanding of diagnostic code conventions, symbols, and terminology.

4. Diagnosis Coding for Outpatient Professional Services
Guidelines for diagnostic coding must be followed when assigning codes
Only diagnoses that currently relate to patient state should be coded
Payment for services may be tied into diagnostic coding, due to medical necessity requirements
A coder must know the current diagnostic coding guidelines, medical terminology, anatomy and physiology, clinical disease processes, and pharmacology.

5. Assigning a Diagnosis Code
Diagnostic coding must be accurate because payment for inpatient services rendered to a patient may be based on the diagnosis
In the outpatient setting, the diagnosis code must correspond to the treatment or services rendered to the patient or payment may be denied
Do not code conditions that relate to a previous medical problem if the conditions have no bearing on the patient’s present condition.

6. Sequencing of Diagnostic Codes
Primary diagnosis (first-listed)
Related to the chief complaint
Main reason for the encounter
Secondary diagnosis
May contribute to the primary diagnosis
Not the underlying cause (etiology)
Principal diagnosis
Only applicable to inpatient cases/claims
Similar to primary diagnosis for outpatient
See Box 5-1 for clarification about primary vs. secondary vs. principal.
Primary and secondary diagnoses are used for outpatient visits. Principal diagnosis is used for inpatient encounters.
What is “etiology?” (The cause of disease; the study of the cause of a disease)

7. Medical Necessity
Insurance companies may not cover procedures that are not diagnosis-related
Reference book is helpful in these situations
For cases dealing with CMS:
Consult regional fiscal intermediary’s website for local coverage determinations (LCDs)
Also consult federal government’s website for national coverage determinations (NCDs)
Procedures that are diagnosis related include most imaging services, cardiovascular services, neurologic services, many laboratory services, and vitamin B12 injections.

8. International Classifications of Diseases
International Classification of Diseases, Tenth Revision, Clinical Modifications (ICD-10-CM)
Used for diagnosis coding for office and outpatient services
International Classification of Diseases, Tenth Revision, Procedure Coding System (ICD-10-PCS)
Used for coding of procedures for inpatient services
Diagnosis coding for outpatient services provided prior to October 1, 2014 is performed using the International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM), Volumes 1 and 2.

9. History Began in England during 17th century
First official version – 1948
United States started using ICD – 1950
Eight revision of ICD (ICDA-8) – 1966
Ninth revision of ICD (ICD-9-CM) – 1979
Tenth revision of ICD (ICD-10-CM) – 1992
Implementation date of October 1, 2014
ICD is developed by the World Health Organization (WHO).

10. Transition from ICD-9-CM to ICD-10-CM
Insurance specialist must be familiar with both ICD-9-CM and ICD-10-CM
Date of service will determine which coding system to use
Noncovered entities are not required to implement ICD-10.
Process of locating a diagnosis code is the same in both coding systems
Coding manuals are organized similarly
Alphabetic index used for locating main term
Tabular index to verify selected code
Both coding systems have a neoplasm table and a table of drugs and chemicals included in the alphabetic index.

11. Transition from ICD-9-CM to ICD-10-CM
ICD-10-CM exceeds previous systems
Number of concepts and codes provided
Expanded to include health-related conditions
Provides greater specificity
Reporting to sixth-digit level with seventh-digit characters
ICD-10-CM allows more code choices and requires greater documentation in the medical record.
The appropriate conventions and Official Coding Guidelines for the specific coding system (ICD-9-CM versus ICD-10-CM) being used should be referenced any time codes are selected to ensure accurate reporting.

12. Crosswalks General equivalence mappings (GEMs)
Used to accurately and effectively translate codes
Used to convert data from ICD-9 to ICD-10 (forward mapping) and vice versa (backward mapping)
Crosswalk publications and software are now available
Are not exact, but can assist in finding appropriate code ranges
GEMs convert data in a manner similar to dictionaries for other languages (such as English to Spanish translation and Spanish to English translation).

13. ICD-10 Diagnosis and Procedure Codes
Benefits to adoption of ICD-10
Much greater specificity
Includes laterality or ordinality of encounter
Expansion of clinical information
Reduced cross-referencing
Flexibility and easy of expandability
Updated medical terminology and classification of diseases
Ability to compare mortality and morbidity rates
Fewer nonspecific codes than in ICD-9-CM
ICD-10-CM meets HIPAA criteria by providing specific information for outpatient and inpatient procedures, describing medical services using terminology in today’s environment, expanding injury and disease codes and categories, and giving a more precise, clear, and clinical picture of the patient.

14. Alphabetic Index to Diseases and Injuries
Contains:
Tables of Drugs and Chemicals
Neoplasm Table
Index to External Causes
Main code descriptor items are in alphabetical order
Indented subterms, applicable additional qualifiers, descriptors, or modifiers are beneath main terms
See Box 5-2 for an illustration of how Alphabetic Index elements are structured.

15. Alphabetic Index to Diseases and Injuries
Fig. 5-3.

16. Special Points to Remember in Alphabetic Index
Appropriate sites or modifiers listed in alphabetic order under main terms
Examine all nonessential modifiers
Eponyms appear as both main term entries and modifiers under main terms
Look for sub-listed terms in parentheses associated with eponym
Locate closely related terms, code categories, and cross-referenced synonyms
See Figs. 5-4 through 5-6 for examples.

17. Tabular List of Diseases and Injuries
Composed of alphanumeric codes that represent diagnoses
ICD-10-CM codes contain up to seven characters with a decimal point after third character
Digit #1 – alpha character
Digits #2 and #3 – numeric characters
Digits #4 to #7 – alpha or numeric characters
“x” used as placeholder
Save a space for future code expansion
Meet requirement of coding to the highest level of specificity
First three characters are placed to the left of the decimal point and indicate the category.
The remaining digits to the right of the decimal point indicate the etiology, anatomic site, and severity.
The sixth character can signify laterality, the intent of a drug poisoning (intentional self-harm, assault), “with” or “without” a given manifestation, the trimester of a pregnancy, the depth of a skin ulcer, or the nature of an injury.

18. Tabular List of Diseases and Injuries
Fig. 5-2.

19. Special Points to Remember in the Tabular List
Use two more codes when necessary
Search for one code when two diagnoses or a diagnosis with an associated secondary process or complication is present
Use category codes only if there are no subcategory codes
Read all instructional notes provided
See Table 5-1 for an outline of the Tabular List and Alphabetic Index of ICD-10-CM.

20. Diagnostic Code Book Conventions
Abbreviations, punctuation, and symbols
Placeholder character
Seventh characters
Other and unspecified codes
Includes notes
Excludes notes
Default code
Gender and age codes
Selection of a coding manual
See the section in the textbook for more information and examples of these conventions.
See Box 5-3 for the Official ICD-19-CM Code Book Conventions.

21. Practice Diagnostic Coding
Lesson 5.2
Practice Diagnostic Coding
Apply general coding guidelines to translate written descriptions of conditions into diagnostic codes.
Apply chapter-specific coding guidelines to reporting of specific illnesses and conditions.
Relate additional coding guidelines specific to reporting of outpatient services.

22. Practice Diagnostic Coding (cont’d)
Lesson 5.2
Practice Diagnostic Coding (cont’d)
Describe methods of becoming more familiar with codes commonly encountered in your office.
Demonstrate the ability to abstract medical conditions from the medical record and accurately assign diagnostic codes by completing the problems in the Workbook.

23. General Coding Guidelines
Locating a code in the ICD-10-CM
Locate term in Alphabetic Index
Verify term in the Tabular List
Dash (-) at end of Alphabetic Index entry indicates additional character required
Determined by Tabular List
Step-by-step procedures for selected ICD-10-CM diagnostic codes are presented at the end of this chapter.
Even if a dash is not present, it is necessary to always refer to the Tabular List to refer to all additional instructional notes.

24. General Coding Guidelines
Level of detail in coding
ICD-10-CM codes composed of 3, 4, 5, 6, or 7 characters
Always code to the highest level of specificity
A code is invalid if it has not been coded to the full number of characters required for that condition.

25. General Coding Guidelines
Signs and symptoms
No precise diagnosis can be made
Signs and symptoms are transient, and a specific diagnosis was not made
Provisional diagnosis for a patient who does not return for further care
A patient is referred for treatment before a definite diagnosis is made
See Examples 5-2 through 5-6.
Guidelines for coding signs and symptoms is different in hospital health information management departments.

26. General Coding Guidelines
Conditions that are an integral part of a disease process
Signs and symptoms should not be assigned as additional codes
Conditions that are not an integral part of a disease process
Signs and symptoms should be reported when documented
Multiple coding for a single condition
“Use additional code”
“Code first”
“Use additional code” notes from the Tabular List will guide the coder as when it is appropriate to report a secondary code. When determined which code to sequence first, the additional code would be reported as a secondary code.
“Code first” notes are also indicated in the Tabular List and are typically used to identify an underlying condition. The underlying condition is always reported as the primary code.

27. General Coding Guidelines
Acute, subacute, and chronic conditions
Code acute (subacute) sequence first, followed by chronic condition code
Combination code
Single code used to classify two diagnoses, or
Diagnosis with associated secondary process (manifestation)
Diagnosis with associated complication
Identify a combination code by referring to sub-term entries in the Alphabetic Index and by reading the inclusion and exclusion notes in the Tabular List.
If the combination code does not specifically describe the manifestation or complication, then use a secondary code.

28. General Coding Guidelines
Sequela
Condition produced after the acute phase of an illness
Also called a “late effect”
Impending or threatened condition
Should be referenced as such in the Alphabetic Index and reported accordingly
There is no time limit on when a late effect code can be used.
Coding of sequel generally required two codes. The nature of the sequel is sequence first; the sequel code is sequenced second.
If there is no sub-term under “impending” or “threatened” for the condition described, report the existing underlying condition(s).

29. General Coding Guidelines
Reporting the same diagnosis more than once
Each diagnosis code may be reported only once for an encounter
Laterality
Final character of code should reflect laterality
The right side is always character 1 and the left side character 2. In those situations when a bilateral code is given, the bilateral character is always 3.
If the side is not identified, an unspecified code is provided, which is either a character 0 or 9, depending on whether it is a fifth or sixth digit character.

30. General Coding Guidelines
Documentation for BMI and pressure ulcer stages
Patient’s provider must document associated diagnosis (obesity, pressure ulcer)
Syndromes
Symptom complex
Reported by following Alphabetic Index
Documentation of complications of care
Assigned based on provider’s documentation of relationship between condition and the care or procedure
Define syndrome or symptom complex. (A set of complex signs, symptoms, or other manifestations resulting from a common cause or appearing in combination, presenting a distinct clinical picture of a disease or inherited abnormality.)

31. Chapter-Specific Coding Guidelines
Human Immunodeficiency Virus
Neoplasms
Coding of diabetes mellitus
Circulatory system conditions
Hypertension
Myocardial infarctions
Pregnancy, delivery, or abortion
See the section of the textbook related to chapter-specific coding guidelines.
In additional to general diagnosis coding guidelines, there are guidelines specific to the 21 chapters of the Tabular Index.
Some of the most frequently referenced chapter-specific coding guidelines are provided in this text; however the insurance billing specialist must be familiar with the entire contents of the Official Coding Guidelines and refer to them when reporting all conditions.
The chapter-specific guidelines are located in Section I, Subsection C of the Official Coding Guidelines.

32. Chapter-Specific Coding Guidelines
Injury, poisoning, and other consequences of external causes
Injuries and late effects
Burns and corrosions
Adverse effects, poisoning, underdosing, and toxic effects
External causes of morbidity
Factors influencing health status and contact with health services
Encounters for reproductive services
See pgs
In additional to general diagnosis coding guidelines, there are guidelines specific to the 21 chapters of the Tabular Index.
Some of the most frequently referenced chapter-specific coding guidelines are provided in this text; however the insurance billing specialist must be familiar with the entire contents of the Official Coding Guidelines and refer to them when reporting all conditions.
The chapter-specific guidelines are located in Section I, Subsection C of the Official Coding Guidelines.

33. Diagnostic Coding and Reporting Guidelines for Outpatient Services
Outpatient surgery
Uncertain diagnosis
Chronic disease
Code all documented conditions that coexist
Patients receiving diagnostic services only
Preoperative evaluations
General medical examinations with abnormal findings
See the section in the textbook related to diagnostic coding and reporting guidelines for outpatient services.
Section IV of the Official Coding Guidelines contains a set of rules specific to reporting of outpatient services that the health insurance specialist should be familiar with.
The guidelines are approved for use for reporting of hospital-based outpatient services and provider-based office visits.
The guidelines are used in conjunction with the general and disease specific guidelines.

34. Handy Hints in Diagnostic Coding
Identify important references with a colored highlighter
Add table to main section of Alphabetic Index, Tabular List, and Drug and Chemical Table
Keep a list of diagnostic and CPT procedure codes commonly encountered by your office
Consult payer guidelines
AMA publishes a list of the most common diagnostic codes at the end of each of their mini-specialty code books
Some medical practices develop an encounter form that is an all-encompassing billing document
Reference books that show codes that link between diagnostic and procedure codes are available.
Refer to the end of this chapter to learn how to locate and select diagnostic codes step-by-step.

35. Computer-Assisted Coding
Computer software automatically generates medical codes of review, validation, and use based on clinical documentation provided by health care practitioners
Two technology options:
Structured input
Data entry screens with point-and-click fields, pull-down menus, structure templates, or macros.
NLP
Uses artificial medical intelligence
Many factors have pushed medical practices to adopt CAC.
NLP systems must be regularly updated to address new medical terminology and conform to changes in coding guidelines.

36. Questions?