Drug Allergy Documentation and Medical Coding

by | Published on Jun 5, 2018 | Medical Coding

Drug Allergy Documentation
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Different from a drug side effect or drug toxicity, a drug allergy is more likely with certain medications. According to the American Academy of Allergy, Asthma & Immunology, about 5-10% of the American population is allergic to various medicines. Adverse reaction to various drugs or medicines is common in the U.S. population. Depending on the specific medication, these reactions often come with symptoms such as drowsiness, dizziness, upset stomach, blurred vision, wheezing or breathing difficulties, tightness in the chest, fainting, weakness, fall in blood pressure, fever, hives, rashes, itching, tachycardia, weak pulse, paleness and vomiting. It is critical for allergy specialists to instruct their medical coding outsourcing service providers or clinical staff to be specific about the drug reaction the patient experienced, and to document which drug caused the reaction.

Some of the common medicines that are more likely to cause allergic reaction in patients are – penicillin, aspirin, non-steroidal anti-inflammatory medications, anticonvulsants, chemotherapy, and monoclonal antibody therapy. Treatment involves the use of antihistamines, corticosteroids, treatment of anaphylaxis, withdrawal of the drug, and others. According to a report published by Market Research Future, the Americas dominate the global market for drug allergy. This report predicts the global drug allergy market to grow at a CAGR of 5.1% during the forecast period 2018-2023 and is estimated to reach USD 4764.0 million by this period.

Allergy reaction is different from drug intolerance. While an allergic reaction occurs when the immune system overreacts to a harmless substance, intolerance to drugs does not involve the immune system, but may produce similar symptoms.


It is recommended that

  • While documenting an adverse effect for a drug that was correctly prescribed and properly administered, code for the side effect, adverse effect of the drug as well as the underlying treated condition that necessitated the drug
  • Code all documented conditions that coexisted at the time of the encounter/visit, and required or affected patient care treatment or management
  • Never code conditions that were previously treated and no longer exist
  • Use history codes as secondary codes if the historical condition or family history has an impact on current care or influences treatment

To document an adverse effect from a properly prescribed and administered hydrocodone drug that resulted in chronic pain due to lumbosacral spinal stenosis and intervertebral disc disorders in the thoracic region with radiculopathy and other side effects, applicable codes include:

    • K59.03 Drug induced constipation
    • T40.2X5A Adverse effect of other opioids, initial encounter
    • M48.07 Spinal stenosis, lumbosacral region
    • M51.14 Intervertebral disc disorders with radiculopathy, thoracic region
    • G89.29 Other chronic pain

In the same way, to document an allergic reaction to properly administered penicillin medication for cellulitis of the buttock that resulted in anaphylactic shock, include

  • T88.6XXA Anaphylactic reaction due to adverse effect of correct drug or medicament properly administered, initial encounter
  • T36.0X5A Adverse effect of penicillin, initial encounter
  • L03.317 Cellulitis of buttock

Other guidelines provided by the American Academy of Allergy Asthma & Immunology to code penicillin allergy include

  • For patients with an anaphylactic reaction to penicillin correctly administered, first use ICD-10-CM code T88.6XXA,D, followed by the code T36.0x1A
  • For those who developed urticaria from penicillin, use the code L50.0, followed by the code T36.0x1A
  • The status code for penicillin, Z88.0 can be used as a primary code for allergy testing, as most payers have this code on their list as a payable diagnosis code

HIPAA-compliant medical coding companies can assist allergy specialists to submit clean claims and thus ensure accurate and timely reimbursement.

Julie Clements

Julie Clements, OSI’s Vice President of Operations, brings a diverse background in healthcare staffing and a robust six-year tenure as the Director of Sales and Marketing at a prestigious 4-star resort.

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