Description:
<jats:title>Abstract</jats:title><jats:p><jats:bold>Selective abdominal vein catheterization with blood sampling for serotonin determination was evaluated regarding its use in the diagnosis, location, and characterization of carcinoids. Serotonin was determined in a platelet‐poor plasma fraction (PPP) by an enzymatic procedure</jats:bold>.</jats:p><jats:p><jats:bold>In 5 normal subjects the concentration of serotonin in PPP in the celiac artery, the hepatic vein, and different intestinal and pancreatic veins ranged from 1.2 to 5.4 ng/ ml. In 10 patients with carcinoid tumors, the concentration of serotonin in tumor‐draining veins was clearly elevated and ranged from 10 ng/ml to 88 ng/ml PPP. 5‐HIAA urine levels were false‐negative in 4 cases, liver scintiscan was false‐negative in 3 cases, and the angiograms were not conclusive in 2 cases</jats:bold>.</jats:p><jats:p><jats:bold>The technique with plasma serotonin determination in combination with selective catheterization is a useful complement to other investigative techniques in the diagnosis, location, and follow‐up of patients with carcinoid tumors</jats:bold>.</jats:p>