The Central Office on HCPCS has received many requests regarding diagnostic coding and reporting guidelines for outpatient services. Although, this newsletter addresses specific HCPCS coding issues, we felt that publication of these guidelines would be beneficial in assisting with the coding and reporting of diagnostic conditions identified in the hospital outpatient setting. A complete set of the ICD-9-CM Official Guidelines for Coding and Reporting can be found in Coding Clinic for ICD-9-CM, Second Quarter 2002, pages 21-71. Refer to Fourth Quarter 1999, pages 24-26, for information on “Patient’s Reason for Visit.”
These coding guidelines for outpatient diagnoses have been approved for use by hospitals and physicians for the coding and reporting of hospital-based outpatient services and physician office visits.
The terms encounter and visit are often used interchangeably in describing outpatient service contacts and, therefore, appear together in these guidelines without distinguishing one from the other.
Although coding conventions and general coding guidelines apply to all settings, outpatient coding guidelines for physician and facility-based reporting of diagnoses vary in some instances from inpatient diagnostic coding guidelines, recognizing that:
The Uniform Hospital Discharge Data Set (UHDDS) definition of principal diagnosis applies only to inpatients in acute, short-term, general hospitals. Coding guidelines for inconclusive diagnoses (probable, suspected, rule out, etc.) were developed for inpatient reporting and do not apply to outpatients.
Information about the use of certain abbreviations, punctuation, symbols, and other conventions listed in ICD-9-CM’s Tabular List under the code numbers and titles can be found at the end of this section, titled “Conventions for the ICD-9-CM.”
Basic coding guidelines for outpatient services
A. Selection of first-listed condition
In the outpatient setting, the term first-listed diagnosis is used in lieu of principal diagnosis.
In determining the first-listed diagnosis the coding conventions of ICD-9-CM, as well as the general and disease-specific guidelines take precedence over the outpatient guidelines.
Diagnoses often are not established at the time of the initial encounter/visit. It may take two or more visits before the diagnosis is confirmed.
The most critical rule involves beginning the search for the correct code assignment through the Alphabetic Index. Never begin searching initially in the Tabular List as this will lead to coding errors.
C. For accurate reporting of ICD-9-CM diagnosis codes, the documentation should describe the patient’s condition, using terminology which includes specific diagnoses as well as symptoms, problems, or reasons for the encounter. There are ICD-9-CM codes to describe all of these.
D. The selection of codes 001.0 through 999.9 will frequently be used to describe the reason for the 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.).
E. Codes that describe symptoms and signs, as opposed to diagnoses, are acceptable, for reporting purposes when a diagnosis has not been established (confirmed) by the physician. 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.
F. ICD-9-CM provides codes to deal with encounters for circumstances other than a disease or injury. The Supplementary Classification of factors Influencing Health Status and Contact with Health Services (V01.0- V83.02) is provided to deal with occasions when circumstances other than a disease or injury are recorded as diagnosis or problems.
G. Level of Detail in Coding
1. ICD-9-CM is 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 specificity.
2. 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. See also discussion under Section I, General Coding Guidelines, Level of Detail, located in Coding Clinic for ICD-9-CM, Second Quarter 2002, pages 31-32.
H. List first the ICD-9-CM code for the diagnosis, condition, problem, or other reason for encounter/visit shown in the medical record to be chiefly responsible for the services provided. List additional codes that describe any coexisting conditions.
I. Do not code diagnoses documented as “probable,” “suspected,” “questionable,” “rule out,” or working diagnosis. Rather, code the condition(s) to the highest degree of certainty for that encounter/visit, such as symptoms, signs, abnormal test results, or other reason for the visit.
Please note: This differs from inpatient coding practices utilized by acute care or short-term hospital medical record departments.
J. Chronic diseases treated on an ongoing basis may be coded and reported as many times as the patient receives treatment and care for the condition(s).
K. Code all documented conditions that coexist at the time of the encounter/visit, and require or affect patient care treatment or management. Do not code conditions that were previously treated and no longer exist. However, history codes (V10- V19) may be used as secondary codes if the historical condition or family history has an impact on current care or influences treatment.
L. For patients receiving diagnostic services only during an encounter/visit, sequence first the diagnosis, condition, problem, or other reason for encounter/visit shown in the medical record to be chiefly responsible for the outpatient services provided during the encounter/visit. Codes for other diagnoses (e.g., chronic conditions) may be sequenced as additional diagnoses.
M. For patients receiving therapeutic services only during an encounter/visit, sequence first the diagnosis, condition, problem, or other reason for encounter/visit shown in the medical record to be chiefly responsible for the outpatient services provided during the encounter/visit. Codes for other diagnoses (e.g., chronic conditions) may be sequenced as additional diagnoses.
The only exception to this rule is that when the primary reason for the admission/encounter is chemotherapy, radiation therapy, or rehabilitation, the appropriate V code for the service is listed first, and the diagnosis or problem for which the service is being performed listed second.
N. For patient’s receiving preoperative evaluations only, sequence a code from category V72.8, Other specified examinations, to describe the pre-op consultations. Assign a code for the condition to describe the reason for the surgery as an additional diagnosis. Code also any findings related to the pre-op evaluation.
O. For ambulatory surgery, code the diagnosis for which the surgery was performed. If the postoperative diagnosis is known to be different from the preoperative diagnosis at the time the diagnosis is confirmed, select the postoperative diagnosis for coding, since it is the most definitive.
P. For routine outpatient prenatal visits when no complications are present codes V22.0, Supervision of normal first pregnancy, and V22.1, Supervision of other normal pregnancy, should be used as principal diagnoses. These codes should not be used in conjunction with chapter 11 codes.
Go to CMS’s Web site, www.cms.hhs.gov/manuals/pm_trans/ab01144.pdf for transmittal AB-01-144, for additional information and examples of appropriate reporting of outpatient diagnosis.