The ACTH test fails to diagnose adrenal insufficiency and augments cytokine production in sepsis.

The adrenocorticotropic hormone (ACTH) test diagnoses relative adrenal insufficiency (RAI) or critical illness-related corticosteroid insufficiency (CIRCI). Initially, guidelines recommended corticosteroid/glucocorticoid (GC) therapy for septic patients with RAI, but later trials did not show a survival benefit, leading to updated guidelines that abandon targeting RAI or CIRCI. Recent studies with an RAI mouse model showed a clear survival benefit from GC therapy in mice with RAI, suggesting that inconclusive GC clinical trials might be due to issues with the ACTH test rather than targeting RAI. To investigate, we performed the ACTH test in septic mice. Interestingly, the ACTH test identified most mice as having adrenal insufficiency in early and middle stages of sepsis, even those with a normal adrenal stress response. Surprisingly, the ACTH test increased inflammatory cytokines to lethal levels, moderately increasing mortality in septic mice. This study revealed significant flaws in the ACTH test for diagnosing RAI/CIRCI. It not only fails to correctly identify these conditions, leading to misguided use of GCs, but also induces a lethal inflammatory response in sepsis. These findings suggest that inconclusive GC therapy trials may be due to the problematic nature of the ACTH test rather than ineffectiveness of targeting RAI/CIRCI.