Overview

Androstenedione (A4) is a steroid hormone produced primarily by the adrenal glands, ovaries (in women), and testes (in men). It serves as a precursor to both testosterone and estrogen and plays a crucial role in sexual development and reproductive function.

Purpose of the Test

The Androstenedione test is used to:

• Evaluate adrenal gland function.
• Diagnose conditions related to androgen excess, such as polycystic ovary syndrome (PCOS), congenital adrenal hyperplasia (CAH), or adrenal tumors.
• Monitor treatment for adrenal disorders.
• Investigate symptoms of excessive or deficient androgen production, such as hirsutism (excess hair growth), acne, menstrual irregularities, or ambiguous genitalia in infants.

Risk Assessment & Clinical Significance

High Androstenedione Levels May Indicate:

• Polycystic ovary syndrome (PCOS) – A common cause of androgen excess in women.
• Congenital adrenal hyperplasia (CAH) – A genetic disorder causing enzyme deficiencies, leading to excessive androgen production.
• Adrenal tumors or adrenal hyperplasia – Overproduction of adrenal androgens.
• Ovarian tumors – In women, some ovarian tumors produce excess androgens.
• Cushing's syndrome – Excess cortisol production, which can lead to increased androgens.

Low Androstenedione Levels May Indicate:

• Adrenal insufficiency (Addison’s disease) – A condition where the adrenal glands fail to produce enough hormones.
• Hypopituitarism – A disorder causing reduced hormone production from the pituitary gland.
• Certain enzyme deficiencies – Such as 17α-hydroxylase deficiency, affecting steroid hormone synthesis.

Normal Range of Androstenedione (A4)

(Normal values may vary depending on the laboratory and testing method.)

• Men: 0.6 – 3.1 ng/mL (2.1 – 10.7 nmol/L)
• Women (Premenopausal): 0.7 – 3.1 ng/mL (2.4 – 10.7 nmol/L)
• Women (Postmenopausal): 0.3 – 2.0 ng/mL (1.0 – 7.0 nmol/L)
• Children (varies by age and puberty stage).

Interpretation of Results

The interpretation of Androstenedione levels depends on age, sex, and clinical context:

1. Elevated Levels – Suggest androgen excess and may require further tests (e.g., testosterone, DHEA-S, cortisol, ACTH stimulation test).
2. Low Levels – Indicate adrenal or gonadal insufficiency and may warrant additional hormone testing.
3. Borderline Results – Often require repeated testing and correlation with other hormone levels.

Sample Type & Test Procedure

• Sample Type: Blood sample (Serum or Plasma)
• Collection Method: Venipuncture (Blood drawn from a vein, usually in the arm)
• Fasting Requirements: Typically, fasting is not required unless instructed by the doctor.
• Best Time for Testing: Usually in the morning when hormone levels are highest.