G90.81
BillableSerotonin syndrome
This code does not map to an HCC category in any model (V28, V24, ESRD, RxHCC).
What This Code Means
Serotonin syndrome is a potentially serious condition that occurs when there is too much serotonin activity in the body, usually caused by taking certain medications together or in high doses. Symptoms can include agitation, confusion, rapid heart rate, high blood pressure, muscle rigidity, and fever.
Coding Tips
- •Always document the triggering medication(s) or combination of drugs that caused the serotonin syndrome, as this helps establish medical necessity and supports clinical decision-making
- •Code any associated symptoms or complications separately (such as fever, muscle rigidity, or altered mental status) if they are documented and clinically significant, as serotonin syndrome often presents with multiple manifestations
Use Additional Code
- code for adverse effect, if applicable, to identify drug, such as:
- linezolid (T36.8X5)
- monoamine oxidase inhibitors (T43.1X5)
- selective serotonin and norepinephrine reuptake inhibitors [SSNRI] (T43.215)
- selective serotonin reuptake inhibitors [SSRI] (T43.225)
- code, if applicable, to identify:
- disseminated intravascular coagulation (D65)
- hypertensive crisis (I16.-)
- metabolic acidosis (E87.2-)
- shock, not elsewhere classified (R57.-)
- toxic encephalopathy (G92.-)
- ventricular tachycardia (I47.2-)
Code First
- poisoning due to drug or toxin, such as:
- linezolid (T36.8X- with sixth character 1-4)
- monoamine oxidase inhibitors (T43.1X with sixth character 1-4)
- selective serotonin and norepinephrine reuptake inhibitors [SSNRI] (T43.21 with sixth character 1-4)
- selective serotonin reuptake inhibitors [SSRI] (T43.22 with sixth character 1-4)