Purpose of review: Although clinicians often rely on experience and anecdote to diagnose Cushing syndrome and its subtypes, clinical decision-making is increasingly influenced by hierarchical evidence-based criteria. Spectrum effect refers to the variability of diagnostic test performance across different populations. The objective of this review is to discuss spectrum effect in the evaluation of Cushing syndrome and to alert the clinician and clinical investigator to a phenomenon that commonly affects diagnostic tests. Recent findings: Most of the diagnostic tests used for Cushing syndrome have been developed and tested in highly specialized referral centers following rigid diagnostic test protocols that may not be accurately reproduced when the tests are applied in medical practice within the community. Because of an increasing concern to raise awareness of this issue, thorough evaluation of the performance of diagnostic tests is advocated. To avoid spectrum effect, investigators should include a heterogeneous group of patients and perform subgroup analyses by stratifying on the characteristic defining the subgroup. Summary: Failure to identify and address the spectrum effect ultimately may erroneously confirm or exclude the diagnosis of Cushing syndrome and its subtypes.
- Cushing syndrome
ASJC Scopus subject areas
- Internal Medicine
- Endocrinology, Diabetes and Metabolism