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Coding Tip of the Month – January 2020

Coding Tip:  Adverse Effect vs Poisoning

It is sometimes difficult to understand which column to use when looking at the Table of Drugs and Chemicals. It may seem to be an adverse effect when a patient presents with dizziness and confusion after ingesting Valium but understanding the difference between an adverse effect and poisoning will assist in correct code abstraction.  The severity of the manifestation should not be used to determine if a reaction is an adverse effect or a poisoning.

An adverse effect is when a drug has been correctly prescribed and correctly administered. In other words, everything was done properly. The correct person took the correct drug as correctly prescribed by a provider. An adverse effect can be as mild as a rash or itching or as severe as hemorrhaging, renal failure or respiratory failure. Adverse effects are sometimes called side effects by drug manufactures. When coding for an adverse effect, the manifestation should be coded first then a code from the Therapeutic Use column.

A poisoning is coded when there has been an improper use of a drug or medication. This can be that the patient was prescribed the medication incorrectly or has taken it incorrectly. Examples of poisoning are:

  • Error was made in the prescription (wrong medication, wrong person, wrong route)
  • Intentional overdose
  • A non-prescribed substance was taken with a correctly prescribed and properly administered drug
  • An interaction with alcohol or other drugs

Poisoning codes are sequenced first with a code from the Poisoning column. Additional codes are used for the manifestation(s) of the poisoning followed by a code from one of the intent columns (suicide attempt, assault, or undetermined).

If a patient takes less medication than what a provider prescribes or in accordance with the manufacturer’s instruction, then it is considered an underdosing. These are not assigned as principal or first-listed codes. If the patient has an exacerbation or relapse of the medical condition for which the drug was prescribed, then the medical condition should be coded. There are codes for non-compliance or complication of care that can be used as additional codes.

In the example of the patient with dizziness and confusion after taking Valium, if the prescribed drug was taken by the right person in the right way then the code sequence would be dizziness, confusion, Therapeutic Use code.

If the patient had taken extra Valium due to a stressful dinner where alcohol was consumed, then codes from the Poisoning column for Valium and alcohol would be sequenced first followed by the dizziness and confusion. The final codes would be taken from the Undetermined column since it was not documented that this was a suicide attempt or an assault.

Reference: ICD-9-CM and ICD-10-CM Official Guidelines for Coding and Reporting