1. Use of Both Alphabetic Index and Tabular List

    Use both the Alphabetic Index and the Tabular List when locating and assigning a code. Reliance on only the Alphabetic Index or the Tabular List leads to errors in code assignments and less specificity in code selection.

Example

Patient presents with threatened miscarriage. She is discharged home the next day with viable pregnancy. Threatened miscarriage: Under the main term “threatened” and the subterm “miscarriage” in the Alphabetic Index, code 640.0 is listed. If the coder were to assign this code, it would be an invalid code. Verification in the Tabular List reveals that a fifth digit is required. The correct code assignment for “threatened miscarriage” is 640.03. (See Figures 5-1 and 5-2.)

2. Locate each term in the Alphabetic Index

    Locate each term in the Alphabetic Index and verify the code selected in the Tabular List. Read and be guided by instructional notations that appear in both the Alphabetic Index and the Tabular List. (See Figures 5-3 and 5-4.)

3. Level of Detail in Coding

    Diagnosis and procedure codes are to be used at their highest number of digits available.

    ICD-9-CM diagnosis codes are composed of codes with either 3, 4, or 5 digits. Codes with three digits are included in ICD-9-CM as the heading of a category of codes that may be further subdivided by the use of fourth and/or fifth digits, which provide greater detail.

    A three-digit code is to be used only if it is not further subdivided. Where fourth-digit subcategories and/or fifth-digit subclassifications are provided, they must be assigned. A code is invalid if it has not been coded to the full number of digits required for that code. For example, Acute myocardial infarction, code 410, has fourth digits that describe the location of the infarction (e.g., 410.2, Of inferolateral wall), and fifth digits that identify the episode of care. It would be incorrect to report a code in category 410 without a fourth and fifth digit.

    ICD-9-CM Volume 3 procedure codes are composed of codes with either 3 or 4 digits. Codes with two digits are included in ICD-9-CM as the heading of a category of codes that may be further subdivided by the use of third and/or fourth digits, which provide greater detail.

4. Code or codes from 001.0 through V91.99

    The appropriate code or codes from 001.0 through V91.99 must be used to identify diagnoses, symptoms, conditions, problems, complaints, or other reason(s) for the encounter/visit.

5. Selection of codes 001.0 through 999.9

    The selection of codes 001.0 through 999.9 will frequently be used to describe the reason for the admission/encounter. These codes are from the section of ICD-9-CM for the classification of diseases and injuries (e.g., infectious and parasitic diseases; neoplasms; symptoms, signs, and ill-defined conditions, etc.).

6. Signs and symptoms

    Codes that describe symptoms and signs, as opposed to diagnoses, are acceptable for reporting purposes when a related definitive diagnosis has not been established (confirmed) by the provider. Chapter 16 of ICD-9-CM, Symptoms, Signs, and Ill-defined conditions (codes 780.0-799.9) contain many, but not all codes for symptoms.

7. Conditions that are an integral part of a disease process

    Signs and symptoms that are associated routinely with a disease process should not be assigned as additional codes, unless otherwise instructed by the classification.

8. Conditions that are not an integral part of a disease process

    Additional signs and symptoms that may not be associated routinely with a disease process should be coded when present.

9. Multiple coding for a single condition

    In addition to the etiology/manifestation convention that requires two codes to fully describe a single condition that affects multiple body systems, there are other single conditions that also require more than one code. “Use additional code” notes (Figure 5-5) are found in the tabular at codes that are not part of an etiology/manifestation pair where a secondary code is useful to fully describe a condition. The sequencing rule is the same as the etiology/manifestation pair—, “use additional code” indicates that a secondary code should be added.

    For example, for infections that are not included in chapter 1, a secondary code from category 041, Bacterial infection in conditions classified elsewhere and of unspecified site, may be required to identify the bacterial organism causing the infection. A “use additional code” note will normally be found at the infectious disease code, indicating a need for the organism code to be added as a secondary code.

    “Code first” notes (Figure 5-6) are also under certain codes that are not specifically manifestation codes but may be due to an underlying cause. When a “code first” note is present and an underlying condition is present the underlying condition should be sequenced first.

    “Code, if applicable, any causal condition first”, notes indicate that this code may be assigned as a principal diagnosis when the causal condition is unknown or not applicable. If a causal condition is known, then the code for that condition should be sequenced as the principal or first-listed diagnosis.

    Multiple codes may be needed for late effects, complication codes and obstetric codes to more fully describe a condition. See the specific guidelines for these conditions for further instruction.

10. Acute and Chronic Conditions

    If the same condition is described as both acute (subacute) and chronic, and separate subentries exist in the Alphabetic Index at the same indentation level (Figure 5-7), code both and sequence the acute (subacute) code first.

11. Combination Code

    A combination code is a single code used to classify:

    Two diagnoses, or

    A diagnosis with an associated secondary process (manifestation)

    A diagnosis with an associated complication

    Combination codes are identified by referring to subterm entries in the Alphabetic Index and by reading the inclusion and exclusion notes in the Tabular List.

    Assign only the combination code when that code fully identifies the diagnostic conditions involved or when the Alphabetic Index so directs. Multiple coding should not be used when the classification provides a combination code that clearly identifies all of the elements documented in the diagnosis. When the combination code lacks necessary specificity in describing the manifestation or complication, an additional code should be used as a secondary code.

12. Late Effects

    A late effect is the residual effect (condition produced) after the acute phase of an illness or injury has terminated. There is no time limit on when a late effect code can be used. The residual may be apparent early, such as in cerebrovascular accident cases, or it may occur months or years later, such as that due to a previous injury. Coding of late effects generally requires two codes sequenced in the following order: The condition or nature of the late effect is sequenced first. The late effect code is sequenced second.

Example

Scoliosis (neuromuscular) due to past history of poliomyelitis, 138, 737.43 (M41.40, B91).

This is an example of the exception to sequencing the residual first. In the Alphabetic Index, under the main term “scoliosis” and the subterm “due to poliomyelitis,” the 138 (cause) is listed first with the scoliosis code 737.43 in brackets. This means that 138 must be sequenced first (Figure 5-8).

13. Impending or Threatened Condition

    Code any condition described at the time of discharge as “impending” or “threatened” as follows:

    If it did occur, code as confirmed diagnosis.

    If it did not occur, reference the Alphabetic Index to determine if the condition has a subentry term for “impending” or “threatened” and also reference main term entries for “Impending” and for “Threatened.”

    If the subterms are listed, assign the given code.

    If the subterms are not listed, code the existing underlying condition(s) and not the condition described as impending or threatened.

14. Reporting Same Diagnosis Code More than Once

    Each unique ICD-9-CM diagnosis code may be reported only once for an encounter. This applies to bilateral conditions or two different conditions classified to the same ICD-9-CM diagnosis codes.

15. Admission/Encounters for Rehabilitation

    When the purpose for the admission/encounter is rehabilitation, sequence the appropriate V code from category V57, Care involving use of rehabilitation procedures, as the principal/first-listed diagnosis. The code for the condition for which the service is being performed should be reported an additional diagnosis.

    Only one code from category V57 is required. Code V57.89, Other specified rehabilitation procedures, should be assigned if more than one type of rehabilitation is performed during a single encounter. A procedure code should be reported to identify each type of rehabilitation therapy actually performed.

16. Documentation for BMI and Pressure Ulcer Stages

    For the Body Mass Index (BMI) and pressure ulcer stage codes, code assignment may be based on medical record documentation from clinicians who are not the patient’s provider (i.e., physician or other qualified healthcare practitioner legally accountable for establishing the patient’s diagnosis), since this information is typically documented by other clinicians involved in the care of the patient (e.g., a dietitian often documents the BMI and nurses often documents the pressure ulcer stages). However, the associated diagnosis (such as overweight, obesity, or pressure ulcer) must be documented by the patient’s provider. If there is conflicting medical record documentation, either from the same clinician or different clinicians, the patient’s attending provider should be queried for clarification.

    The BMI and pressure ulcer stage codes should only be reported as secondary diagnoses. As with all other secondary diagnosis codes, the BMI and pressure ulcer stage codes should only be assigned when they meet the definition of a reportable additional diagnosis (see Section III, Reporting Additional Diagnoses).

17. Syndromes

    Follow the Alphabetic Index guidance when coding syndromes. In the absence of index guidance, assign codes for the documented manifestations of the syndrome.

18. Documentation of Complications of care

    Code assignment is based on the provider’s documentation of the relationship between the condition and the care or procedure. The guideline extends to any complications of care, regardless of the chapter the code is located in. It is important to note that not all conditions that occur during or following medical care or surgery are classified as complications. There must be a cause-and-effect relationship between the care provided and the condition, and an indication in the documentation that it is a complication. Query the provider for clarification, if the complication is not clearly documented.