Internal Medicine Coding Alert

Published on Thu Jul 01, 1999 PDF

Your internist sees a patient who has suffered an adverse reaction to a drug prescribed by the physician. How should you correctly report the ICD-9 codes to indicate the medical necessity of the office visit? If you look at the Table of Drugs and Chemicals in ICD-9-CM, you may be confused. Should you choose the poisoning codes? The
E codes for adverse or late effects? In what order
should multiple ICD-9 codes indicating adverse drug effects be listed?

The answers to these questions will vary with the specific clinical situation, and it is essentialboth for a reimbursement and a medical recordkeeping perspectivethat the ICD-9 codes are reported correctly. Internal Medicine Coding Alert consulted two coding experts to determine correct strategy for reporting poisonings and adverse drug effects. Using their advice and information published in the ICD-9-CM, here are our three steps to correct diagnosis coding for drug reactions:

1. How was the drug taken? Simply put, the coder should start with whether the drug was taken correctly by the patient or whether the patient took the drug in an inappropriate manner, says Kathryn Cianciolo, MA, RRA, CCS, CCS-P, chair of the Society for Clinical Coding in Waukesha, WI, and an independent medical practice management consultant. According to the American Hospital Associations (AHA) guidelines and ICD-9-CM, an adverse reaction to a drug prescribed by a doctor should not be coded as a poisoning unless the drug was taken in a manner not in accordance with a physicians instructions, she says.

According to the guidelines, an adverse reaction
occurs when a medication is properly administered and correctly prescribed and the patient has an ill effect.
Examples include accumulative effects (drug toxicity),
allergic reactions, hypersensitivity, interaction between prescribed drugs, side effects, and idiosyncratic, synergistic, and paradoxical effects. Chronic effects of a drug taken over a long period of time and are still being taken are also coded as adverse reactions.

A poisoning should be coded if the reaction is caused by drugs, medications or other substances that are not used in accordance with a physicians instruction. Examples of poisoning include overdose/suicide; the wrong dosage is given or taken; the wrong dosage is given or taken; a medication (prescription or non-prescription) and alcohol combination; a prescription drug taken with an over-the-counter drug; or illegal drug usage or intoxication (other than a cumulative effect).

In addition, situations in which the cause of the adverse reaction is not immediately known should be reported as poisoning, says Jeri Leong, RN, CPC, an independent medical practice management consultant and a certified coding instructor in Honolulu, HI. An example would be if a child is found unconscious and later is determined to be unconscious due to an accidental ingestion of acetaminophen. (See coding examples in next column.)

2. For adverse reactions, code signs and
symptoms first. If the patient has an adverse reaction to a drug taken correctly, the coder should first report the diagnosis code that indicates the manifestation or nature of the adverse reaction, states Cianciolo.

For example, if a patient comes to the physicians office after taking a prescribed dosage of insulin, but is experiencing light-headedness and blurred vision, the coder should first report the symptoms: 780.4 (dizziness and giddiness, whirling sensations in the head with falling sensation, light-headedness), and 368.8 (other specified visual disturbance, blurred vision NOS).

Next, the coder should find the drug that the patient took in the Table of Drugs and Chemicals and select the appropriate E code for therapeutic use. In this case, the code would be E932.3.

3. Report poisoning codes for drugs taken
incorrectly. If a patient has taken the wrong drug or takes the correct drug in the incorrect dosage, the coder should first report the poisoning code for the drug taken. For example, in the case of an incorrect dosage of insulin, the coder would look up insulin in the table and report 962.3.

Next, the codes for signs and symptoms that indicate the manifestation of the poisoning should be reported (i.e., dizziness, headache, etc.). Third, the coder should then choose the appropriate E code to indicate the external cause of the poisoning (i.e., assault, accidental ingestion, etc.), although these codes are optional.

The code for accidental ingestion of a drug or chemical is listed in the column just to the right of the poisoning codese.g., for insulin the code would be E858.8.

I encourage all coders to use these E codes for external causes, though payers do not always require them, adds Leong. These codes help to clarify the incident and provide accurate statistics.

Note: Do not use the E code column therapeutic use for poisonings.

4. Code late effects. Late effects of adverse reactions or poisonings (effect that remains after the acute phase of the reaction has passed) should also be reported, says Cianciolo.

The correct sequence for this situation is:

A. Code the residual effect first (e.g., the remaining effect).

B. Assign a late effect code (i.e., 909.5, late effect of adverse effect of drug, medical, or biological substance or 909.0, late effect of poisoning due to drug, medicinal or biological substance).

C. Then, code the reaction the same as an immediate drug reaction.

Diagnosis Coding Examples of Drug Reactions

Scenario One:

A child is brought to the physicians office unconscious after ingesting a bottle of aspirin. The following ICD-9 codes should be used:

965.1 Poisoning by salicylates
780.09 Other alteration of consciousness
E850.3 Accidental poisoning by salicylates

Scenario Two:

A patient was given Bhloropromazine for severe nausea and vomiting. The patient takes the drug according to instructions, but, after a short time, the patient develops vertigo and headache and returns to the physician for a change in medication. The following ICD-9 codes should be used:

780.4 Vertigo
784.0 Headache
E939.1 Adverse effects in therapeutic use, phenothiazine-based tranquilizers.

Source: ICD-9-CM.