A False-Positive Response in Dexamethasone Testing

Excerpt

To the editor: The standardization of serum cortisol responses to low- and high-dose dexamethasone testing for Cushing's syndrome reported by Ashcraft and colleagues (1) is an economic and technical advance. We wish to report a false-positive study secondary to estrogen administration and also to show the nonspecificity of acid phosphatase values determined in the prostate by the substrate-specific enzymatic method.

An 81-year-old man with probable metastatic adenocarcinoma of the prostate was hospitalized for bone pain that was not relieved by diethylstilbestrol. The patient had a bone biopsy that showed adenocarcinoma of unknown primary site, and a computed tomographic scan showed