What this test measures
Androstenedione (A4) is a steroid hormone made roughly 50:50 by the adrenal glands and the gonads. It sits in the steroid pathway between DHEA and testosterone — it is a precursor that the body converts to testosterone (and from there to estrogen in fat tissue).
A4 is measured in serum by immunoassay or, more accurately, by LC-MS/MS. Levels follow a diurnal rhythm (higher in the morning) and a menstrual rhythm in women (higher mid-cycle).
Why it matters
A4 is most commonly checked in the workup of hyperandrogenism in women — hirsutism (excess facial/body hair), severe or late-onset acne, scalp hair loss, deepening voice, or menstrual irregularity. The big-three causes of hyperandrogenism in Indian women are PCOS, non-classic CAH and (rarely) androgen-secreting tumours; A4 is part of the standard biochemical panel along with total/free testosterone, DHEA-S, 17-OHP and SHBG.
A4 that is disproportionately high relative to testosterone and DHEA-S can point to non-classic CAH or an androgen-producing ovarian tumour. Very high values (> 5× upper limit) in a woman with rapidly progressive virilisation warrant urgent imaging.
How to prepare
Morning sample (between 8 and 10 am) is preferred — A4 has a diurnal rhythm. In cycling women, draw in the early follicular phase (cycle day 2–5) for the cleanest baseline. Fasting is not required. Stop biotin / cosmetic supplements for 48–72 hours before. Continue other medications.
Markers & reference ranges
Reference ranges below are typical adult values. Your lab's reported range may differ slightly based on the assay platform and patient demographics — always read your report against the range printed on it.
| Marker | Normal range | If low | If high |
|---|---|---|---|
| Androstenedione (ng/dL)[1][2] | Adult female: 35 – 250 ng/dL · Adult male: 40 – 150 ng/dL · Tanner 1 (pre-pubertal): < 50 | Low A4 with low cortisol and low DHEA-S suggests adrenal insufficiency. Low A4 with low testosterone in men suggests hypogonadism. | Raised A4 in a woman = hyperandrogenism. Modest rises (up to 2× normal) are typical of PCOS. Higher rises with raised 17-OHP suggest non-classic CAH. Very high A4 (> 5×) with rapidly progressive virilisation = androgen-secreting adrenal or ovarian tumour until proven otherwise. |
A4 in the hyperandrogenism workup
| Pattern | A4 | Testosterone | DHEA-S | 17-OHP | Likely cause |
|---|---|---|---|---|---|
| PCOS | Mildly raised | Mildly raised | Normal/mildly raised | Normal | Polycystic ovary syndrome (most common) |
| Non-classic CAH | Raised | Raised | Normal/raised | Raised | 21-hydroxylase deficiency |
| Adrenal androgen tumour | Very high | Raised | Very high | Normal/raised | Adrenal adenoma / carcinoma |
| Ovarian androgen tumour | Very high | Very high | Normal | Normal | Ovarian Sertoli-Leydig or other tumour |
| Idiopathic hirsutism | Normal | Normal/upper end | Normal | Normal | Increased peripheral androgen sensitivity |
Frequently asked questions
Why is androstenedione being checked along with my testosterone?
A4 and testosterone come from different sources — A4 is half adrenal, half gonadal; testosterone is mostly ovarian/testicular. Measuring both helps separate adrenal from ovarian causes of androgen excess.
I have PCOS — will A4 always be high?
Not always. About half of women with PCOS have mildly raised A4 (up to twice the upper limit). A normal A4 does not rule out PCOS — the diagnosis is based on clinical, hormonal and ultrasound criteria together.
What if my A4 is much higher than expected?
Very high A4 (more than five times the upper limit), especially with rapidly progressive hair growth, deepening voice or clitoromegaly, raises concern for an androgen-secreting adrenal or ovarian tumour. Your doctor will likely order imaging — adrenal CT and pelvic ultrasound.
Does the time of day matter?
Yes — A4 follows a diurnal rhythm (higher in the morning). Always sample between 8 and 10 am for consistency.
What about my menstrual cycle?
A4 rises mid-cycle. For the clearest baseline, draw on cycle day 2–5 (early follicular phase). If you do not have regular periods, your doctor will pick a convenient day.
I am a man — why is my doctor checking A4?
A4 is occasionally part of the workup for gynaecomastia (breast tissue growth in men), infertility, or suspected testicular tumour. It is also part of the panel for late-onset CAH in men.
How is A4 different from DHEA-S?
DHEA-S is almost entirely adrenal — a very high DHEA-S points strongly to the adrenal gland. A4 is half adrenal, half gonadal — it shows the overall androgen production but does not localise the source.
Related Hormones / Endocrine tests
Tests commonly ordered alongside ANDROSTENEDIONE (A4), or that help interpret an unexpected result.
Sources & references
- Endocrine Society — Hirsutism in Premenopausal Women · accessed 2026-05-30T00:00:00.000Z
- NCBI StatPearls — Androstenedione · accessed 2026-05-30T00:00:00.000Z
- Mayo Clinic Laboratories — Androstenedione, Serum · accessed 2026-05-30T00:00:00.000Z
- NIH MedlinePlus — Androstenedione · accessed 2026-05-30T00:00:00.000Z
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