Underdosing of diagnostic agents, initial encounter

This code signifies that a patient received an insufficient amount of a diagnostic agent, such as a contrast dye or a radiopharmaceutical, which resulted in a suboptimal diagnostic study or an inability to complete the diagnostic procedure as intended. This underdosing can lead to inconclusive results, requiring repeat studies or alternative diagnostic approaches.

Apply this code when documentation clearly indicates that a diagnostic agent was administered in a dose lower than what was therapeutically or diagnostically required. This could occur due to medication errors, patient-specific factors affecting absorption or metabolism, or equipment malfunction leading to incomplete delivery of the agent. This code is specifically for the initial encounter where the underdosing occurred.

• Always sequence this code after the code(s) for the condition being investigated by the diagnostic agent.
• Ensure documentation specifies "underdosing" and not simply a failed diagnostic study without a clear cause.
• Verify that the encounter is the "initial encounter" for the underdosing event; subsequent encounters would use the appropriate subsequent encounter or sequela codes.