A Study Of The Correlation Between The Examinations Of Metanephrines And The Diagnosis Of Pheochromocytoma

Aim:To investigate the expression of metanephrine(MN) in the tissue and the plasma free metanephrines(MNs) levels of pheochromocytoma patients for the diagnosis.Method:Immunohistochemistry was used to detect metanephrine in the tissue samples. Enzyme-linked immunosorbent assay(ELISA) was used to analyse the level of plasma free metanephrine and plasma free normetanephrine(NMN) in these patients' samples.The result was compared with the test data from 24-hour urinary epinephrine(E) and norepinephrine(NE) tests of these patients.Results:The results of immunochemistry tests on the pheochromocytoma group revealed a positive rate of 75.86%(22/29),however,the adrenocortical disease group did not display any positive result(0/8).ELISA results:The plasma free MNs tests revealed the sensitivity and specificity results of 100%and greater than 93.18%.The area under the receiver operating characteristic(ROC) curve(AUC) of plasma free MNs were greater than 0.995,but the AUC of urinary epinephrine(E) and norepinephrine (NE) were only 0.842 and 0.829.There was no significant statistical difference between the MNs levels of silent pheochromocytoma and non-silent pheochromocytoma groups,two of the pheochromocytoma subgroups(P=0.503, 0.148).The positive detection rate of the silent group was 100%,but the positive detection rates of the 24-hour urinary E and NE tests were 50%and 25%.Conclusion:(1) The sensitivity and specificity results of plasma free MNs were 100% and greater than 93.18%.(2) Plasma free MNs gave a much better overall evaluation of the diagnosis of pheochromocytoma than the urinary E and NE test did.(3) Plasma free MNs were not affected by different clinical function gradation and the silent pheochromocytoma group revealed a positive detection rate of 100%.