These coding guidelines for outpatient diagnoses have been approved for use by hospitals/ providers in coding and reporting hospital-based outpatient services and provider-based 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. Though the conventions and general guidelines apply to all settings, coding guidelines for outpatient and provider reporting of diagnoses will vary in a number of instances from those for inpatient diagnoses, recognizing that:
The Uniform Hospital Discharge Data Set (UHDDS) definition of principal diagnosis does not apply to hospital-based outpatient services and provider-based office visits.
Selection of the 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-10-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.
When a patient presents for outpatient surgery (same-day surgery), code the reason for the surgery as the first-listed diagnosis (the reason for the encounter), even if the surgery is not performed due to a contraindication.
When a patient is admitted for observation for a medical condition, assign a code for the medical condition as the first-listed diagnosis. When a patient presents for outpatient surgery and develops complications requiring admission to observation, code the reason for the surgery as the first reported diagnosis (the reason for the encounter), followed by codes for the complications as secondary diagnoses.
Codes from A00.0 through T88.9, Z00-Z99
The appropriate code(s) from A00.0 through T88.9, Z00-Z99 must be used to identify diagnoses, symptoms, conditions, problems, complaints, or other reason(s) for the encounter/visit.
Accurate reporting of ICD-10-CM diagnosis codes
For accurate reporting of ICD-10-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-10-CM codes to describe all of these.
Codes that describe symptoms and signs
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 provider. Chapter 18 of ICD-10-CM, Symptoms, Signs, and Abnormal Clinical and Laboratory Findings Not Elsewhere Classified (codes R00-R99) contain many, but not all codes for symptoms.
Encounters for circumstances other than a disease or injury
ICD-10-CM provides codes to deal with encounters for circumstances other than a disease or injury. The Factors Influencing Health Status and Contact with Health Services codes (Z00-Z99) are provided to deal with occasions when circumstances other than a disease or injury are recorded as diagnosis or problems.
Level of Detail in Coding
- ICD-10-CM codes with 3, 4, 5, 6 or 7 characters: ICD-10-CM is 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, fifth, sixth or seventh characters to provide greater specificity.
- Use of the full number of characters required for a code: 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.
ICD-10-CM code for the diagnosis, condition, problem, or other reason for encounter/visit
List first the ICD-10-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. In some cases, the first-listed diagnosis may be a symptom when a diagnosis has not been established (confirmed) by the provider.
Do not code diagnoses documented as “probable”, “suspected,” “questionable,” “rule out,” “compatible with,” “consistent with,” or “working diagnosis” or other similar terms indicating uncertainty. 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.
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)
Code all documented conditions that coexist
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 (categories Z80- Z87) may be used as secondary codes if the historical condition or family history has an impact on current care or influences treatment.
Patients receiving diagnostic services only
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.
For encounters for routine laboratory/radiology testing in the absence of any signs, symptoms, or associated diagnosis, assign Z01.89, Encounter for other specified special examinations. If routine testing is performed during the same encounter as a test to evaluate a sign, symptom, or diagnosis, it is appropriate to assign both the Z code and the code describing the reason for the non-routine test.
For outpatient encounters for diagnostic tests that have been interpreted by a physician, and the final report is available at the time of coding, code any confirmed or definitive diagnosis (es) documented in the interpretation. Do not code related signs and symptoms as additional diagnoses.
Patients receiving therapeutic services only
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 or radiation therapy, the appropriate Z code for the service is listed first, and the diagnosis or problem for which the service is being performed listed second.
Patients receiving preoperative evaluations only
For patients receiving preoperative evaluations only, sequence first code from subcategory Z01.81, Encounter for pre-procedural 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.
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.
Encounters for general medical examinations with abnormal findings
The subcategories for encounters for general medical examinations, Z00.0- and encounter for routine child health examination, Z00.12-, provide codes for with and without abnormal findings. Should a general medical examination result in an abnormal finding, the code for general medical examination with abnormal findings should be assigned as the first-listed diagnosis. An examination with abnormal findings refers to a condition/diagnosis that is newly identified or a change in the severity of a chronic condition (such as uncontrolled hypertension, or an acute exacerbation of chronic obstructive pulmonary disease) during a routine physical examination. A secondary code for abnormal findings should also be coded.
In fee-for-service medicine, physician services are paid based on the fee associated with the CPT or HCPCS code submitted on the claim form. The diagnosis code supports the medical necessity for the service and tells the payer why the service was performed. It can be the source of denial if it doesn’t show the medical necessity for the service performed.
Diagnostic and procedural codes are connected to nearly every system and business process in health plans and provider organizations, including reimbursement and claim processes. For smoother claim processing and reduced denials, equal attention to diagnosis coding is important. MedicalBillersandCoders (MBC) systematically connects diagnosis and procedural codes ensuring timely payments from insurance carriers. To know more about our medical coding and billing services you contact us at email@example.com