A Faster Way to Diagnose Cushing Syndrome

Diagnosing Cushing syndrome (CS) can take 24 hours of complicated and repeated analyses of blood and urine, brain imaging, and tissue samples from sinuses. But that may soon be in the past. The NIH researchers have found that measuring cortisol levels in hair samples can do the same job, faster.

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Patients with CS have a high level of cortisol, perhaps from a tumor of the pituitary or adrenal glands or as an adverse effect from medications. In a study, 36 participants—30 with CS, 6 without—provided hair samples divided into 3 equal segments. The researchers found that the segments closest to the scalp had the most cortisol (96.6 ± 267.7 pg/mg for CS patients, vs 14.1 ± 9.2 pg/mg in control patients). Those segments’ cortisol content correlated closest with the majority of the initial biochemical tests, including in blood taken at night (when cortisol levels normally drop).

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The study was small, CS is rare, and it’s hard to recruit large numbers of patients. Still, the researchers believe it is the largest of its kind to compare hair cortisol levels with diagnostic tests in patients with CS. “Our results are encouraging,” said Mihail Zilbermint, MD, the study’s senior author, and an endocrinologist at NIH’s Eunice Kennedy Shriver National Institute of Child Health and Human Development. “We are hopeful that hair analysis may ultimately prove useful as a less-invasive screening test for Cushing syndrome or in helping to confirm the diagnosis.” The researchers suggest that the test also is a convenient alternative with the “unique ability” for retrospective evaluation of hypercortisolemia over months.