What are First-listed diagnosis in ICD-10 CM?

Selection of first-listed condition in ICD-10 CM

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.

Example:

Established 50-year-old patient was seen in the clinic for acute bronchitis. Patient also received a prescription for a refill of medication for hypertension. The first-listed diagnosis is acute bronchitis.
Initial office visit for a 36-year-old female complaining of irregular menses. Review of systems identified unexplained weight loss. The first-listed diagnosis is irregular menses.
Established patient is a 75-year-old male complaining of substernal chest pain, which is relieved with rest. Patient has hypertension and blood pressure is above baseline on this visit. The first-listed diagnosis is substernal chest pain.

Most physicians will document the “chief complaint” of the patient for each encounter in the medical record. The chief complaint (CC) is the reason the patient presents for the medical visit. The CC is one of the keys to determining the first-listed diagnosis. The chief complaint is the reason for the visit from the patient’s perspective. For example, a patient consumed a soup that contained shellfish. The patient is allergic to shellfish, and develops hives. The chief complaint and the first-listed diagnosis is allergic hives, due to allergy to shellfish.

Other times, the patient’s complaint is a symptom of a more complex diagnosis. For example, a patient presents with a chief complaint of a backache, and after examination, the physician determines the patient has an acute kidney infection due to Escherichia coli. The chief complaint is a backache, but the first-listed diagnosis is an acute kidney infection due to E. coli. The backache was a symptom of the acute kidney infection.

The patient may also schedule a visit without a chief complaint. As examples, the patient requests a physical to qualify for insurance or may be an expectant parent seeking to establish a pediatrician. The reason for these visits can be reported as first-listed codes using appropriate Z code.