Serum Cortisol Test
2,750 Kshs | Home Collection Available
Synonyms
cortisol AM&PM
Purpose
The Cortisol Test measures the amount of cortisol, a steroid hormone produced by the adrenal glands in the blood. Cortisol plays a key role in regulating metabolism, blood pressure, immune response, and the body’s stress response.
This test is important for diagnosing disorders related to abnormal cortisol levels, such as Cushing’s syndrome (too much cortisol) and Addison’s disease (too little cortisol). It helps assess adrenal gland function and the body’s ability to handle stress.
The test can be performed alongside ACTH (Adrenocorticotropic Hormone) Test, Urinary Free Cortisol Test, Dexamethasone Suppression Test, Electrolyte Panel, and Aldosterone and Renin Levels.
These additional tests help provide a complete picture of adrenal and hormonal health.
Patient Preparation
The patient should avoid taking biotin supplements for at least 72 hours before sample collection.
Samples
1ml with a minimum volume of 0.7ml of serum collected in a red top tube or gel barrier tube. Transfer separated serum to a plastic transport tube if a red top tube is used. Store the sample at room temperature.
Reference Range
AM:6.2-19.4µg/dL; PM:2.3-11.9µg/dL
Results Turnaround
1-2 days after receipt of samples.
Diseases / Diagnostic indicators
The Cortisol Test is associated with the diagnosis of disorders involving the adrenal glands, hypothalamus, and pituitary gland. These organs work together in the hypothalamic-pituitary-adrenal (HPA) axis to regulate cortisol production.
High cortisol levels may indicate:
- Cushing’s syndrome – often due to adrenal tumors or long-term steroid use
- Stress – physical or emotional stress can temporarily raise cortisol
- Pituitary tumors – producing excess ACTH (Cushing’s disease)
- Adrenal hyperplasia – overactive adrenal glands
Low cortisol levels may suggest:
- Addison’s disease – underactive adrenal glands
- Hypopituitarism – reduced ACTH production by the pituitary
- Adrenal insufficiency – due to long-term steroid use or autoimmune damage
Clinicians interpret the results in context, often using ACTH levels and other hormone tests to accurately diagnose the underlying condition. For more on the Serum Cortisol Test, read this study.