J45Asthma

J45 is the ICD-10-CM diagnosis code for asthma. It belongs to block J40-J4B (chronic lower respiratory diseases) and chapter 10 (diseases of the respiratory system). It is a header code, so it can't be reported by itself; one of its 5 subcodes must be used instead.

To report this condition, pick the subcode that matches the documentation: J45.2 (asthma), J45.3 (asthma), J45.4 (asthma), J45.5 (asthma) and J45.9 (asthma).

Don't report J45 together with the conditions in its Excludes1 note: detergent asthma (J69.8), miner's asthma (J60), wheezing NOS (R06.2) and wood asthma (J67.8).

The conditions in its Excludes2 note aren't part of J45, but may be coded alongside it if the patient has both: asthma with chronic obstructive pulmonary disease (J44.89), chronic asthmatic (obstructive) bronchitis (J44.89), chronic obstructive asthma (J44.89) and other specified chronic obstructive pulmonary disease (J44.89).

Use an additional code to identify: eosinophilic asthma (J82.83), exposure to environmental tobacco smoke (Z77.22), exposure to tobacco smoke in the perinatal period (P96.81), history of tobacco dependence (Z87.891), occupational exposure to environmental tobacco smoke (Z57.31) and 2 more.

It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.