ICD 10 Coding Alert

Whether you’re new to coding or you’re a seasoned professional, mastering the basics of ICD-10-CM requires consistent review.

If you want to perfect your ICD-10-CM coding skills, start by going back to the basics in three ways: know how to code signs and symptoms, understand how to correctly sequence conditions, and recognize when to submit a provider query for clarification.

Remember the Rules for Coding Signs and Symptoms

ICD-10-CM Official Guidelines for Coding and Reporting include this foundational principle: Code confirmed diagnoses rather than signs and symptoms when the provider lists both the diagnosis and symptoms in the patient’s medical record.

For example, say a provider documents acute bacterial pneumonia with cough and fever. In this case, use J13 (Pneumonia due to Streptococcus pneumoniae), and do not separately code R05.1 (Acute cough) or R50.81 (Fever presenting with conditions classified elsewhere).  

That said, there are four main scenarios where coding signs and symptoms is correct and necessary. The first is when the patient does not yet have a definitive diagnosis. This is common in outpatient settings because diagnostic testing may still be in progress.

For example, if a patient’s medical record states “chest pain, workup pending, no diagnosis yet,” use the appropriate code from the I20.- (Angina pectoris) set.

Second, if a symptom that is not typically associated with a confirmed condition is clinically significant and listed in the documentation, coders may code the symptom separately. For instance, if a patient’s medical record states “urinary tract infection with confusion” and the provider indicates that the confusion is clinically relevant and not inherent to the infection, select N39.0 (Urinary tract infection, site not specified) and separately code R41.0 (Disorientation, unspecified).

In some cases, a symptom may justify diagnostic tests or treatments beyond what is typical for the diagnosis. If the provider clearly documents the symptom as distinct and clinically meaningful, coders may report the symptom separately. For example, a provider evaluates a patient for acute maxillary sinusitis. During the visit, the provider documents new-onset diplopia that is not typical for uncomplicated sinusitis. Concerned about possible orbital involvement, the provider orders urgent CT imaging and documents the diplopia as a separate, clinically significant finding. In this case, separately code J01.00 (Acute maxillary sinusitis, unspecified) and H53.2 (Diplopia).

Finally, do not code uncertain diagnoses in outpatient settings. Phrases that flag uncertain diagnoses include “suspected,” “probable,” “rule out,” and “likely.” Instead, code the documented signs and symptoms. If a patient’s record states “possible appendicitis; right lower quadrant pain,” select R10.31 (Right lower quadrant pain), not K35.80 (unspecified acute appendicitis).

Keep in mind that inpatient facility coding does allow coding of probable or suspected conditions if the provider documents the symptom at discharge.

Maintain Correct Sequencing

ICD-10-CM Official Guidelines include sequencing rules that override general “first-listed diagnosis” rules.

Conditions that are classified as manifestations of an underlying disease require sequencing. ICD-10-CM often includes instructional notes such as: “Code first underlying condition” or “Use additional code.” For example, if a patient with type 2 diabetes has diabetic neuropathy, code E11.40 (Type 2 diabetes mellitus with diabetic neuropathy, unspecified) first, then G62.9 (Polyneuropathy, unspecified).

Certain ICD-10-CM codes represent manifestations of an underlying condition and cannot be reported as the primary diagnosis. The Tabular List identifies these situations through instructional notes such as “Code first” or “Use additional code.” For example, in hypertensive chronic kidney disease (CKD), ICD-10-CM requires you to sequence the hypertension with CKD code first, followed by the code for the stage of kidney disease. Assign I12.9 (Hypertensive chronic kidney disease with stage 1-4 or unspecified CKD) first, followed by the appropriate code from the N18.- (Chronic kidney disease) set based on the patient’s disease stage. Review both the Tabular List notes and the ICD-10-CM Alphabetic Index before finalizing code order.

In outpatient encounters, the first-listed diagnosis should reflect the chief reason for the visit, even when the patient has more serious chronic conditions. In these cases, the condition requiring evaluation or treatment during the visit determines sequencing. For example, if a patient with stable chronic obstructive pulmonary disease (COPD) presents for treatment of an ankle sprain, the ankle injury is sequenced first. List S93.401A (Sprain of unspecified ligament of right ankle, initial encounter) as the first diagnosis, and report J44.9 (Chronic obstructive pulmonary disease, unspecified) as a secondary condition.

When documentation supports both acute and chronic forms of the same condition, and separate ICD-10-CM codes exist, guidelines generally direct coders to sequence the acute condition first, followed by the chronic condition. For example, when a provider documents acute and chronic systolic heart failure, the correct sequencing assigns I50.21 (Acute systolic (congestive) heart failure) first, followed by I50.22 (Chronic systolic (congestive) heart failure).

When ICD-10-CM provides a combination code that fully describes multiple related conditions, such as type 2 diabetes mellitus and CKD, the correct approach is to assign E11.22 (Type 2 diabetes mellitus with diabetic chronic kidney disease) as the first-listed code and then report an additional code to identify the stage of CKD, such as N18.2 (Chronic kidney disease, stage 2).

Know When a Query Is Appropriate

Distinguishing between signs and symptoms versus confirmed diagnoses is one of the most common gray areas in ICD-10-CM coding, particularly when documentation is incomplete or ambiguous. In these situations, a provider query plays a critical role in supporting accurate code assignment. A query is appropriate when the medical record does not clearly support whether a symptom is integral to a diagnosis, represents a separate condition, or reflects a complication or expected finding, and when clarification is clinically reasonable.

For example, a provider’s assessment may list sepsis alongside fever, while progress notes suggest the fever may be unrelated to the sepsis. In these cases, do not assume a relationship between sepsis and fever; instead, submit a query to clarify whether the fever is attributable to sepsis or should be reported separately.

When objective diagnostic evidence supports a diagnosis, but the provider documents only symptoms, it may be appropriate to submit a query. For instance, say that imaging confirms pneumonia, but the provider documents only cough and hypoxia. In this case, querying the provider can determine whether it’s appropriate to use J18.9 (Pneumonia, unspecified organism) rather than reporting signs and symptoms alone.

Do not assume a causal link between conditions unless ICD-10-CM guidelines explicitly allow it. For example, documentation may list anemia and CKD without stating whether the anemia is related to CKD. Because anemia may be caused by multiple factors, submit a query to clarify whether the anemia is due to CKD, as this affects both code selection and sequencing.

Queries are also valuable when documentation does not clarify whether a finding is an expected response, a complication, or an unrelated condition. For example, a postoperative patient may develop tachycardia. Without additional documentation, it is unclear whether the tachycardia represents a normal postoperative response, a complication of surgery, or an unrelated condition requiring separate reporting. In this case, send a query to the provider to clarify.

Michelle Falci, BA, M Falci Communications LLC