stimulationstest

Stimulationstest, or stimulation test, is a diagnostic procedure used to evaluate how well a biological system responds to a controlled stimulus. By provoking a physiologic pathway with a specific trigger—such as a hormone, a drug, a metabolic load, or a physical stimulus—the test assesses functional reserve and regulatory mechanisms rather than resting function alone. Stimuli can be pharmacologic, metabolic, or physiologic, and responses are measured with timed samples or tests.

In endocrinology, stimulation tests are common tools to assess the pituitary–adrenal axis, thyroid axis, and growth hormone secretion. The ACTH (cosyntropin) stimulation test evaluates adrenal reserve by measuring cortisol before and after administration of synthetic ACTH. A sufficient cortisol rise indicates normal adrenal function, while a blunted response suggests insufficiency. Growth hormone stimulation tests (for example, using insulin-induced hypoglycemia, arginine, clonidine, or glucagon) probe GH secretory capacity, with results compared to age- and sex-adjusted reference ranges. Other stimulation tests, such as TRH or GnRH tests, have more limited or region-specific use.

Procedure and interpretation typically involve baseline measurements, administration of the stimulus, and serial samples collected over a specified time frame. Patient preparation, such as fasting status and medication review, can influence results. Reference values are assay- and lab-dependent, so clinicians interpret results within the local context.

Applications extend to diagnosing endocrine deficiencies or dysregulations, assessing suspected pituitary or adrenal disorders, and evaluating growth disorders in children. Limitations include biological variability, medication effects, and acute illness influencing outcomes. Safety considerations center on monitoring for adverse reactions to the stimulus and the invasive or venous sampling required. See also dynamic endocrine testing and provocative testing.