Nuances and definitions determine how you select the most appropriate code for the situation.
To code adverse effects, assign the appropriate code for the nature of the adverse effect before you code for the adverse effect of the drug itself.
To code an adverse effect, poisoning, underdosing or toxic effect of a substance, begin your search in the Table of Drugs and Chemicals, by drug. But don’t code directly from that table. Instead, always refer back to the tabular list to confirm the correct code — you must know the definition of each term to code accurately.
Find the codes for adverse effects, poisoning, underdosing and toxic effects in Chapter 19 (Injury, Poisoning and Certain Other Consequences of External Causes). This is the largest chapter in the ICD-10-CM manual, therefore, know how to navigate this chapter to accurately code each scenario.
How to code for adverse effects
Coding guidelines define an adverse effect is “a reaction to a drug that has been correctly prescribed and properly administered.” Find the codes for an adverse effect in categories T36 to T50. They have a fifth or sixth character of 5.
Chapter-specific coding guidelines instruct you to “assign the appropriate code for the nature of the adverse effect followed by the appropriate code for the adverse effect of the drug (T36-T50).” [1.C.19.e.5.a]
For example, if a patient had an adverse effect of bradycardia after taking Digoxin, code the bradycardia first, as it is the nature of the adverse effect. Follow this with the T46.0x5D (Adverse effect of cardiac-stimulant glycosides and drugs of similar action, subsequent encounter) code to identify the drug causing the adverse effect.
CODE NOTE: Keep in mind you also code the condition for which the Digoxin was prescribed.
MORE CODE NOTES:
- The codes in categories T36 to T65 are combination codes that include the substance taken as well as the intent; therefore, do not add an external cause code, per coding guidelines.
- Use as many codes as necessary to describe completely all drugs, medicinal or biological substances, coding guidelines state.
- When you assign a seventh character for an adverse effect, poisoning, underdosing or toxic effect, remember “A” indicates active treatment, “D” indicates ongoing care in the healing and recovery phase, and “S” indicates care for a residual condition left behind after the illness or injury has healed, per coding guidelines.