Which code should be assigned first if a condition is due to poisoning?

When a condition is due to poisoning, the most appropriate coding practice is to assign the code for the poisoning first. This approach follows the guidelines set forth by the ICD-10-CM coding system, which emphasizes that the code for the specific substance causing the poisoning takes precedence.

Specifically, the reason for prioritizing the poisoning code is that it directly captures the nature of the event responsible for the patient's current condition. It reflects the acute nature of the poison and provides clarity in documenting the primary reason for the patient's health issues. This code often includes specific details about the substance and the severity of the poisoning, which is important for accurate medical records and billing purposes.

The other potential options would not accurately reflect the coding guidelines in this scenario. The adverse effect code is relevant in cases where the condition results from a negative reaction to a properly administered medication, but it does not apply when the condition stems from an intentional or unintentional exposure to a toxin. Similarly, coding the underlying condition first would not convey the immediate urgency and the critical nature of the poisoning. Therefore, assigning the poisoning code first ensures clear and accurate documentation of the patient’s diagnosis related to the poisoning incident.