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Test ID: ACTH
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Adrenocorticotropic Hormone (ACTH)
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Useful For
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This test measures the amount of ACTH in the blood to help diagnose adrenal gland problems and pituitary diseases such as Cushing syndrome, Cushing disease, adrenal insufficiency (Addison disease), adrenal tumors, and pituitary tumors.
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Method name and description
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Electrochemiluminescence immunoassay (ECLIA) intended for use on the cobas e 801 immunoassay analyzer. Patient specimen, biotinylated monoclonal ACTH‑specific antibody, and a monoclonal ACTH‑specific antibody labeled with a ruthenium complex react to form a sandwich complex. After addition of streptavidin-coated microparticles, the complex becomes bound to the solid phase via interaction of biotin and streptavidin.The reaction mixture is aspirated into the measuring cell where the microparticles are magnetically captured onto the surface of the electrode. Unbound substances are then removed with ProCell II M. Application of a voltage to the electrode then induces chemiluminescent emission which is measured by a photomultiplier Results are determined via a calibration curve which is instrumentspecifically generated by 2‑point calibration and a master curve.
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Clinical information
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Plasma ACTH measurements are useful in the differential diagnosis of Cushing's disease (ACTH hypersecretion), autonomous ACTH producing pituitary tissue (e.g. Nelson's syndrome), hypopituitarism with ACTH deficiency and ectopic ACTH syndrome. In addition to cortisol measurements, ACTH determinations can be used together with suppression or stimulation tests to diagnose the origin of glucocorticoid overproduction. Similarly, ACTH measurements can be employed to facilitate differential diagnosis of adrenocortical insufficiency (Addison’s disease). ACTH concentrations show a diurnal variation with high levels in the morning and low levels in the evening. Therefore, as with cortisol, it is important to know the collection time of the plasma sample for interpretation of the results. (Roche Cobas ACTH package insert).
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Aliases
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Adrenocorticotropin, Corticotropin
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Specimen type / Specimen volume / Specimen container
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Specimen type : Plasma
Minimum volume of sample: 1 mL
Plasma: K2‑EDTA and K3‑EDTA in siliconized glass or plastic tubes (on ice)
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Collection instructions / Special Precautions / Timing of collection
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- Only use pre-cooled sampling vials.
- After drawing the blood, put the vials immediately.on ice.
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Storage and transport instructions
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Storage: 3 hours at 2-8°C
2‑2 hours at 20‑25 °C,
10 weeks at ‑20 °C (±5)
Transport: 2-8°C (sample on ice)
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Specimen Rejection Criteria
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Grossly hemolyzed, icteric and lipemic samples, wrong collection container, insufficient sample and heat‑inactivated samples.
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Biological reference intervals and clinical decision values
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For 7-10 AM Collection : 7.2‑63.3 pg/mL
(The plasma samples were drawn between 7‑ 10 a.m. ACTH concentrations vary considerably depending on physiological conditions. Therefore, ACTH results should always be evaluated together with simultaneously measured cortisol concentrations.)
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Factors affecting test performance and result interpretation
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ACTH concentrations vary considerably depending on physiological conditions. Therefore, ACTH results should always be evaluated together with simultaneously measured cortisol concentrations.
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Turnaround time / Days and times test performed / Specimen retention time
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Daily (24/7)
Turn-around time:
Routine: One working day
Specimen Retention: 4 days
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