What is used for a cosyntropin (adrenocorticotropic hormone) stim test?

From the Guidelines

A cosyntropin stimulation test uses a high-dose of 250 micrograms of synthetic adrenocorticotropic hormone (ACTH), specifically cosyntropin (Synacthen or Cortrosyn), to evaluate adrenal function, as this dose is considered the most practical and accurate for diagnosis 1. The standard protocol involves administering this dose intravenously or intramuscularly, then measuring serum cortisol levels at baseline (before injection) and at 30 and/or 60 minutes after injection. A normal response shows cortisol rising to at least 18-20 μg/dL (500-550 nmol/L), indicating proper adrenal function. For pediatric patients, the dose is typically adjusted to 0.125-0.25 mg. The test requires proper preparation including withholding certain medications like exogenous steroids when possible, as they can interfere with results. Blood samples must be collected at precise time intervals for accurate interpretation. This test is valuable because it directly assesses the adrenal glands' ability to respond to ACTH stimulation, helping diagnose conditions like adrenal insufficiency, Addison's disease, or secondary adrenal suppression from exogenous steroid use. Some key considerations include:

• The high-dose ACTH test is easy to perform and safe 1.
• The likelihood ratio (LR) of a positive test was 9.1 for the high-dose ACTH test, indicating its diagnostic accuracy 1.
• The task force suggested using the high-dose rather than the low-dose ACTH test for the diagnosis of CIRCI due to easier practical modalities and comparable accuracy 1.
• If there is a clinical suspicion of impending acute adrenal crisis, the patient should be given intravenous hydrocortisone immediately and a physiologic saline infusion, and treatment should never be delayed because of the need to carry out diagnostic procedures 1.

From the FDA Drug Label

Cosyntropin for injection is an adrenocorticotropin hormone indicated, in combination with other diagnostic tests, for use as a diagnostic agent in the screening of adrenocortical insufficiency in adults and pediatric patients.

For adults, the recommended dose is 0.25 mg to be administered by intravenous or intramuscular injection.

For pediatric patients, the recommended dose to be administered by intravenous or intramuscular injection is

o 0.125 mg for patients birth to less than 2 years of age o 0. 25 mg for patients 2 to 17 years of age

Cosyntropin is used for a cosyntropin (adrenocorticotropic hormone) stim test. The recommended dose is:

• 0.25 mg for adults, administered by intravenous or intramuscular injection.
• 0.125 mg for pediatric patients birth to less than 2 years of age, administered by intravenous or intramuscular injection.
• 0.25 mg for pediatric patients 2 to 17 years of age, administered by intravenous or intramuscular injection 2.

From the Research

Cosyntropin Stim Test

• The cosyntropin stim test is used to diagnose adrenal insufficiency, and it involves administering a synthetic form of adrenocorticotropic hormone (ACTH) to stimulate the adrenal glands to produce cortisol 3, 4, 5.
• The test can be performed using different doses of cosyntropin, including 1 microg and 250 microg, and the choice of dose may depend on the specific clinical scenario 3, 5.
• The 1-microg cosyntropin stimulation test is considered more sensitive than the 250-microg test for diagnosing secondary adrenal insufficiency in non-stressed patients 3.
• In critically ill patients, the 1-microg test is also likely to be more sensitive than the 250-microg test when an appropriate cutoff value is used 3, 5.
• The test involves measuring cortisol levels at baseline and after administration of cosyntropin, and the results are used to determine if the adrenal glands are functioning properly 4, 6, 7.

Diagnostic Criteria

• A peak cortisol level of less than 18-20 microg/dL is often used as a cutoff for diagnosing adrenal insufficiency 3, 6.
• However, the diagnostic criteria may vary depending on the specific clinical scenario and the assay used to measure cortisol levels 6.
• Some studies suggest that the use of a monoclonal antibody assay may increase the rate of diagnosis of adrenal insufficiency compared to a polyclonal antibody assay 6.

Clinical Applications

• The cosyntropin stim test is commonly used to diagnose adrenal insufficiency in patients with suspected primary or secondary adrenal insufficiency 3, 4.
• It is also used to evaluate adrenal function in critically ill patients and to guide treatment with glucocorticoids 4, 5.
• The test may be used to monitor patients who are receiving high-dose glucocorticoid therapy and to assess the risk of adrenal insufficiency 7.