|5-HIAA (24-hour urine)
|In patients with small-intestine carcinoid NETs decreasing levels may indicate a response to treatment. Diet and medications significantly affect 5-HIAA levels.
‡ Avoid eating avocados, bananas, cantaloupe, eggplant, pineapples, plums, tomatoes, hickory nuts, plantains, kiwi, dates, grapefruit, honeydew or walnuts for 48 hours prior to the start of urine collection. Coffee, alcohol and smoking should also be avoided during this period. Drugs such as acetaminophen, ephedrine, diazepam, nicotine, glyceryl guaiacolate (in some cough syrups) and phenobarbital can also increase 5-HIAA levels.