ACTH Stimulation (Cosyntropin)

Sample type: -

• serum

Uses: -

• Evaluation of possible primary and secondary adrenal insufficiency.

Precautions: -

• The patient may have a fat-free meal prior to testing.

• Although it may make more physiologic sense to perform the test during the nadir of endogenous ACTH production (around midnight) it is usually performed at 8:00-9:00 AM for ease of collection and comparison to normative data that was collected during that timeframe.

• Blood is drawn for baseline studies and the ACTH (1-24) administered intramuscularly or intravenously.

• If intramuscularly, 250 μg for patient weight of ≥37 pounds.

• If intravenously, dilute the cosyntropin in 2 mL to 5 mL of normal saline and inject over two minutes.

• Samples for analysis are collected 60 minutes after administration of the cosyntropin.

Interfere factor: -

• Pregnancy, contraceptives, and estrogen therapy can give rise to elevated cortisol concentrations.

• In samples from patients who have been treated with prednisolone, methylprednisolone, or prednisone, falsely elevated concentrations of cortisol may be determined due to cross-reactivity.

• Patients suffering from 21-hydroxylase-deficiency exhibit elevated 21-deoxycortisol levels, and this can also give rise to elevated cortisol levels. Severe stress can also give rise to elevated cortisol concentrations.

Pre analytical error: -

• Specimen not serum

Corrective action: -

• The sample must be rejected, and another sample be obtained.

Post analytical error: -

• Reports were sent to the incorrect patient

Corrective action: -

• Communication with patient, apologizing for the error, and providing him with the correct report