Otolaryngology Coding Alert

Question: When reporting an asthma diagnosis, do I need a fifth digit?

Washington Subscriber

Answer: Yes. ICD-9 requires you to use a fifth-digit subclassification with asthma codes (493.xx, Asthma). If you submit four digits for an asthma diagnosis, payers will probably reject the ICD-9 code as incomplete.

Correct method: Assign the fourth digit based on the asthma category:

- 493.0x --" Extrinsic asthma

- 493.1x --" Intrinsic asthma

- 493.2x --" Chronic obstructive asthma

- 493.8x --" Other forms of asthma

- 493.9x --" Asthma, unspecified.

Then, identify the asthma's current state with the appropriate fifth digit:

--0 --" unspecified

--1 --" with status asthmaticus

--2 --" with (acute) exacerbation.

For patients who do not have status asthmaticus or acute exacerbation, use a fifth digit of "0." Code 493.x0 is appropriate when the patient's asthma is controlled. A final digit of "1" indicates that the patient has status asthmaticus, which is a medical emergency and is usually treated in the emergency department. You should assign a "2" when something has caused the condition to flare up.

Why it matters: Without this level of specificity, the payer may deny your claim for lack of medical necessity.

Example: An extrinsic asthma patient has an acute exacerbation that requires a nebulizer treatment (94640, Pressurized or nonpressurized inhalation treatment for acute airway obstruction or for sputum induction for diagnostic purposes [e.g.,with an aerosol generator, nebulizer, metered dose inhaler, or intermittent positive pressure breathing (IPPB) device]). In this case, you should link 94640 to 493.02. Reporting a "2" as the fifth digit helps the payer understand why the patient needs the treatment. Without the final digit (or a fifth-digit of "0"), the payer may assume that the patient's asthma is under control, making the coded treatment unnecessary.