Basics of Diagnosis Coding

March 17th, 2015 - Betsy Nicoletti
Categories:   Diagnosis Coding  

Diagnosis coding is the process of translating narrative medical description into a code.

CMS Coding and Reporting Guidelines for diagnosis coding:

  • Use the ICD-9-CM codes that describe the patient's diagnosis, symptom, complaint, condition, or problem.
  • Use the ICD-9-CM code that is chiefly responsible for the item or service provided.
  • Assign codes to the highest level of specificity. Use the fourth and fifth digits when indicated as necessary in your ICD-9-CM volumes.
  • Do not code suspected diagnoses in the outpatient setting. Code only the diagnosis symptom, complaint, condition, or problem reported. Medical records, not claim forms, should reflect that the services were provided for "rule out" purposes.
  • Code a chronic condition as often as applicable to the patient's treatment.
  • Code all documented conditions which coexist at the time of the visit that require or affect patient care or treatment. (Do not code conditions which no longer exist)

ICD-9 Conventions:

Non specific codes

Decimal digits .8 and .9 indicate “other specified” or “non otherwise specified.”  Use only when more specific information is not available, or doesn’t exist, not just “when it is not convenient to get more detailed information.”

NEC (Not elsewhere classified) Used in Volumes 1 and 2

These codes should only be used when a coder lacks precise information necessary to code a term more specifically.

NOS (Not otherwise specified) Used in Volume 1

Etiology codes have "use additional code" notes to indicate when manifestation codes are required and manifestation codes have "code first" notes to indicate when an etiology code is required.

The words "in diseases classified elsewhere" are part of the code title for most ?manifestation codes.

See: Indicates the coder should look up the term specified to find the correct code.

See Also:  Indicates the coder should look up the term specified to find the correct code.

The ICD-9-CM book consists of three volumes.  We use the first two:

Volume 1: Tabular list of Diseases and Injuries

    * Use this volume to select codes

    * Arranged in numerical sequence

    * Contains V codes and E codes

Volume 2 is an Alphabetic Index to Volume 1 and includes:

    *  Alphabetic Index of Diseases and Injuries

    * Table of Drugs and Chemicals

    * Index of External Causes of Injuries and Poisonings

Always begin the initial search for a code with Volume 2, but do not code directly from Volume 2. Coding from Volume 2 can lead to inaccurate codes because:

    *  Not all fifth digits are indicated

    * Include, Exclude, and Notes are not included

V codes are for screening personal history of or family history of.  You are most likely to use them for patients who no longer have active disease or for whom you are doing a screening service. 

E codes are for accidents or incidents, like these.  Motor vehicle accidents are in the range of E-810 to 819; accidental poisonings, E-850 to E-858, and many others. 

    * Code to the highest degree of specificity.  When fourth and fifth digits are available, they must be used.

    * Code the diagnosis, symptom, complaint, condition that is chiefly responsible for the visit

    * If the diagnosis is not known, use symptoms

    * Do not code rule out, probable or possible, use symptoms

    * Code underlying and chronic conditions only if they were considered and documented in today’s visit

    * For multiple injuries: code the most severe first.

    * Limit use of unspecified codes when more specific codes are available and there is definitive information available.

    * For inpatient services, code the reason that lead to admission, then secondary diagnoses.

    * Use acute and chronic conditions when ICD-9 uses those distinctions.

Remember, physician claims are paid based on CPT® code, but denied based on diagnosis code!


Questions, comments?

If you have questions or comments about this article please contact us.  Comments that provide additional related information may be added here by our Editors.

Latest articles:  (any category)

COVID Vaccine Coding Changes as of November 1, 2023
October 26th, 2023 - Wyn Staheli
COVID vaccine changes due to the end of the PHE as of November 1, 2023 are addressed in this article.
Medicare Guidance Changes for E/M Services
October 11th, 2023 - Wyn Staheli
2023 brought quite a few changes to Evaluation and management (E/M) services. The significant revisions as noted in the CPT codebook were welcome changes to bring other E/M services more in line with the changes that took place with Office or Other Outpatient Services a few years ago. As part of CMS’ Medicare Learning Network, the “Evaluation and Management Services Guide” publication was finally updated as of August 2023 to include the changes that took place in 2023. If you take a look at the new publication (see references below),....
Can We Score Interpretation of an EKG Towards E/M Medical Decision Making?
October 10th, 2023 - Aimee Wilcox
When EKGs are performed in the facility setting or even in the physician's office, what are the requirements for reporting the service and who gets credit for scoring data points for Evaluation and Management (E/M) medical decision making (MDM)? Let's take a look at a few coding scenarios related to EKG services to get a better understanding of why this can be problematic.
Accurately Reporting Signs and Symptoms with ICD-10-CM Codes
October 5th, 2023 - Aimee Wilcox
Coders often find themselves unsure of when to report a sign or symptom code documented in the medical record. Some coders find their organization has an EHR that requires a working diagnosis, which is usually a sign or symptom, be entered to order a test or diagnostic study or image. Understanding the guidelines surrounding when signs and symptoms should be reported is the first step in correct coding so let's take a look at some scenarios.
The 2024 ICD-10-CM Updates Include New Codes for Reporting Metabolic Disorders and Insulin Resistance
September 19th, 2023 - Aimee Wilcox
Diabetes is a chronic disease that just seems to consistently be increasing instead of improving resulting in a constant endeavor by medical researchers to identify causal effects and possible treatments. One underlying or precipitating condition that scientists have identified as a precipitating factor in the development of diabetes is insulin resistance, which is a known metabolic disorder. As data becomes available through claims reporting, additional code options become possible with ICD-10-CM.
Documenting and Reporting Postoperative Visits
September 12th, 2023 - Aimee Wilcox
Sometimes we receive questions regarding documentation requirements for specific codes or coding requirements and we respond with information and resources to support our answers. The following question was recently submitted: Are providers required to report postoperative services on claims using 99024, especially if there is no payment for that service? What documentation is required if you are reporting an unrelated Evaluation and Management (E/M) service by the same physician during the postoperative period? 
Understanding Gastroesophageal Reflux Disease and ICD-10-CM Coding
August 22nd, 2023 - Aimee Wilcox
Gastroesophageal reflux disease or GERD for short, is a disease that impacts millions of Americans on a weekly basis. Symptoms are uncomfortable, as are some of the tests used to diagnose it, but understanding the disease, tests, and treatments helps us better understand how to code the disease using ICD-10-CM codes.

Home About Terms Privacy

innoviHealth® - 62 E 300 North, Spanish Fork, UT 84660 - Phone 801-770-4203 (9-5 Mountain)

Copyright © 2000-2023 innoviHealth Systems®, Inc. - CPT® copyright American Medical Association