Response to the Letter to the Editor From Jialal and Sood: "New Cutoffs for the Biochemical Diagnosis of Adrenal Insufficiency After ACTH Stimulation Using Specific Cortisol Assays".

We sincerely thank Drs. Jialal and Sood for allowing us to clarify our report [1]. Drs. Jialal and Sood are correct—the Beckman Access cortisol assay uses a polyclonal cortisol antibody, not a monoclonal antibody as we stated. We apologize for this error in our report. We also appreciate the additional information they provide on extending the reportable range of the Beckman Access cortisol immunoassay [2] as well as highlighting that the cross-reactivity of the cortisol antibody with 11-deoxycortisol can influence the interpretation of metyrapone testing.

As pointed out by Drs. Jialal and Sood, the cosyntropin-stimulated cortisol cutoffs we provided in our report for the Beckman Access cortisol immunoassay are still valid [1].