A. Laurence Kennedy

Overnight High Dose Dexamethasone Suppression Test—8 mg

This test is performed to help differentiate Cushing’s disease from ectopic ACTH syndrome (EAS) in patients with ACTH (adrenocorticotrophic hormone)-dependent Cushing’s syndrome.It is also performed to help differentiate Cushing’s disease from adrenal Cushing’s in patients with low normal plasma ACTH levels.

Overnight Low Dose Dexamethasone Suppression Test—1 mg

This test is performed to evaluate for Cushing’s syndrome and adrenal incidentaloma for subclinical Cushing’s syndrome.

Metyrapone Stimulation Test

This test is performed to evaluate HPA axis integrity. It is a sensitive alternative test to insulin tolerance test (ITT) in order to evaluate the adrenocorticotrophic hormone (ACTH) reserve.

Ovine Corticotropin-Releasing Hormone (oCRH) Stimulation Test

This test is performed to differentiate Cushing’s disease from ectopic and adrenal Cushing’s syndrome.

Combined CRH Dexamethasone Suppression Test

This test is performed to be able to distinguish Cushing’s syndrome from pseudo-Cushing’s states.

Two Day Low Dose Dexamethasone Suppression Test

This test is performed to assess suppressibility of cortisol in patients with an equivocal screening test such as overnight d1-mg examethasone (dex) suppression test, 24 h urinary free cortisol, and/or late night salivary cortisol.

Mixed Meal Hypoglycemia Test

The mixed meal hypoglycemia test is carried out in patients with suspected postprandial hypoglycemia.

ACTH Stimulation Test for Late Onset (Nonclassic) 21-Hydroxylase Deficiency

Indication To evaluate for androgen excess in diagnosing nonclassic CYP21A2 deficiency. If Basal 17-hydroxyprogesterone (17 OHP) < 2 ng/ml, diagnosis is unlikely and ACTH stimulation may not be necessary.

Growth Hormone Suppression Test (Post-Glucose Administration)

Indication To establish the diagnosis of acromegaly when there is modest elevation of IGF-1 (< 2-fold upper limit of normal) with absent or equivocal clinical features [1].

Levothyroxine Absorption Test

Indication To assess poor oral absorption of levothyroxine (LT4), and assist the clinician in differentiating true malabsorption from pseudomalabsorption (patient nonadherence).