Otolaryngology Coding Alert

Don't make allergy diagnosis coding more difficult than it has to be.

Diagnoses involving allergic conditions are notoriously challenging, even to the most seasoned otolaryngology coders. In addition to the sheer number of varying allergy codes, understanding the nuances behind each code in addition to the way some allergy codes play off of other conditions can take quite some time to master.

"When it comes to allergy diagnosis coding, you have to take a look at the broad spectrum of conditions affecting the patient," relays Kimberly Quinlan, CPC, senior medical records coder for the University of Rochester Medical Center's Department of Otolaryngology in Rochester, New York.

Read on for more information on the most practical and effective methods for accurate allergy ICD-10 coding.

Be Wary of T Codes

There's no easy way to approach the task of grasping the fundamentals of allergy coding as a whole. The most practical route is to look at different components of the diagnosis via the ICD-10 index. In many initial encounter visits, the cause of the allergy will be unknown to both the patient and provider.

However, this does not mean that you should opt for the unspecified code T78.40- (Allergy, unspecified...). T codes fall under the category of "Injury, poisoning and certain other consequences of external causes" within the ICD-10-CM. Unless the patient is having an acute allergic reaction, you should not consider a T code diagnosis.

"If a patient presents with allergies of an unspecified nature without an acute allergic reaction taking place, you should only code the signs and symptoms until an allergy test has been performed," explains Barbara J. Cobuzzi, MBA, CPC, CENTC, COC, CPC-P, CPC-I, CPCO, AAPC Fellow, vice president at Stark Coding & Consulting LLC, in Shrewsbury, New Jersey.

In the case that a patient does present with an initial, unspecified allergic reaction, you will opt for code T78.40XA (Allergy, unspecified, initial encounter), indicating that this is the first encounter for the patient's presenting symptoms. Your other seventh digit options are D (Subsequent encounter) and S (Sequela). If the patient is returning for a follow-up after receiving, for example, a nasal spray treatment, the use of the seventh digit D would be appropriate.

Remember: The More Documentation, the Better

Taking a brief look at "allergy" under the ICD-10 index, you'll see the plethora of options you have to choose from. While the unspecified T codes (for allergic reactions) do cross-reference with allergy testing CPT^® codes in the coding crosswalk, the same cannot necessarily be said for evaluation and management (E/M) visits. In order to ensure payment for these encounters, you will want to make sure your provider offers any and all information available surrounding the patient's allergy diagnosis.

The reason for this extends beyond simple reimbursement purposes. The correct allergy ICD-10 code is ultimately dependent on the patient's comorbidities and/or associated diagnoses. Consider the following examples:

Example 1: A patient presents with allergic rhinitis due to pollen and food.

This is a relatively open and shut case. Find allergic rhinitis within the ICD-10 index and apply codes J30.1 (Allergic rhinitis due to pollen) and J30.5 (Allergic rhinitis due to food). The only additional consideration here is the application of a secondary code surrounding the use of or exposure to tobacco smoke, if applicable.

Example 2: A patient presents with allergic rhinitis due to pollen with mild persistent asthma.

A coder with less experience might instinctively make an effort to include a separate code for each diagnosis the provider documents. The provider might even justify the decision using the rationalization that a coder should never make assumptions when it comes to associated diagnoses. However, in this case, the ICD-10 tabular will specifically instruct you to combine these diagnoses.

Under the J30 (Vasomotor and allergic rhinitis...) section of the ICD-10 tabular, you will see that that any J30 code has an Excludes1 for allergic rhinitis with asthma (bronchial) (J45.909). In the instance that allergic rhinitis and unspecified asthma are coded alongside one another, you are instructed to apply code J45.909 (Unspecified asthma, uncomplicated). However, the J30 code description does not include an Excludes 1 option for all forms of asthma, only an unspecified form. "As a result, this Excludes 1 note does not apply to a code for a specified form of asthma, such as mild persistent, with allergic rhinitis," relays Sheri Poe Bernard, CPC, of Poe Bernard Consulting in Salt Lake City, Utah. "For this, you will have to find the code J45.- (Asthma...) in the ICD-10 tabular. Under this code description, you will find 'allergic rhinitis with asthma' under the Includes portion of the code description," Bernard details.

You now have enough justification to code this example exclusively as J45.30 (Mild persistent asthma, uncomplicated). While the use of two separate diagnosis codes offers a substantially higher degree of specificity than the code you're ultimately left with, ICD-10 has final say on these coding determinations.

Note: For a better understanding of how and when to utilize the key term "with" in the ICD-10, re-read page 13 of the ICD-10-CM Official Guidelines for Coding and Reporting.