ED Coding and Reimbursement Alert

Question: We recently had a patient in our ED with an insulin reaction. I am not sure how to choose a diagnosis code for this. Would you explain how to use the applicable codes?

Arizona Subscriber

Answer: Correct code assignment will depend on whether the patient took the medication correctly.

To determine the diagnosis code for drug reactions, coders must identify what caused the reaction, based on the notes provided by the ED physician in the patient record. Poisoning codes should be reported when a drug or substance is taken incorrectly. This includes medications prescribed by a physician and taken in an inappropriate manner, or medication or other substances taken without physician instruction (e.g., a child ingesting a cleaning product, or an adult swallowing an overdose of aspirin).

If the patient on insulin took the drug incorrectly, the coder should look up insulin in the table of drugs and chemicals and report the poisoning code for insulin (962.3, Poisoning by hormones and synthetic substitutes; insulins and antidiabetic agents) first. You should then code any signs and symptoms related to the adverse reaction, (e.g., 780.4, Dizziness and giddiness, 787.02, Nausea alone, 780.2, Syncope and collapse). Next, report an E code for the "external cause" of the poisoning. These are also listed next to the name of the drug in the table of drugs and chemicals. For example, if the patient accidentally took too much insulin, you should assign E858.0 (Accidental poisoning by other drugs; hormones and synthetic substitutes).

If the physician does not know which substance caused the adverse effect, you should use 995.2 (Unspecified adverse effect of drug, medicinal and biological substance).

If a patient takes the insulin (or other drug) correctly and still has an adverse reaction, the coder should first report the codes of the signs and symptoms that indicate that reaction (e.g., 780.4). Next, the coder should report the E code for "therapeutic use" found in the table of drugs and chemicals next to the name of the drug. In this case, the code would be E932.3 (Hormones and synthetic substitutes; insulins and antidiabetic agents). This code is only used when the drug has been taken according to instructions. But it is never reported as a primary diagnosis code. The signs and symptoms indicating that patient's reaction should be coded first.

Note: Some coding experts recommend that hypoglycemia or diabetes [e.g., 250.01, Diabetes mellitus without mention of complication; type I, not stated as uncontrolled], the condition that initially required the insulin, be reported in the first position.