Carcinoid syndrome: biochemical diagnosis
Sorina Schipor1, Ana-Maria Stefanescu1, Diana-Loreta Paun1,2, Constantin Dumitrache1,2 & Corin-Virgil Badiu1,2
Objective: To introduce the best biochemical strategy for carcinoid syndrome diagnosis.
Patients and methods: We selected two groups of patients: one group of 75 patients suspected of carcinoid syndrome: 57 women aged between 19 and 78 years and 18 men aged 1781 years and a 80 healthy subjects group without endocrine disfunction: 56 women aged between 27 and 78 years and 24 men aged 1781 years. We established median values for all parameters in carcinoid group versus normal group as it follows: serotonin (5-HT): 248 vs 124 ng/ml; 5-hydroxy-indole-acetic acid (5-HIIA): 7 vs 2.7 mg/24 h and chromogranin A (CgA): 296 vs 59 ng/ml.
We introduced the analysis of receiver operating characteristic curves (ROC) for all parameters assayed and it was possible to calculate optimal threshold values corresponding to maximal accuracy (ACC) as it follows: for 5-HT: 200 ng/ml (0.8452); for 5-HIIA: 4 mg/24 h (0.7548) and for CgA: 99 ng/ml (1.0000). The software relies on a non-parametric test for the difference of the area under the ROC curve (AUC). We calculated AUC differences between different parameters and also the confidence intervals (95% CI) as it follows: CgA/5-HT: 0.0858 (0.04143, 0.13023); CgA/5-HIIA: 0.2318 (0.15486, 0.30881); 5-HT/5-HIIA: 0.1460 (0.07669, 0.21531).
Conclusion: Our statistics revealed CgA as the best diagnostic marker for carcinoid syndrome: true positive results (tp): 100% followed by 5-HT: tp: 68% and by 5-HIIA: tp: 61.33%.