PMOS / PCOS tests: which blood tests, and how to get tested
This page explains the blood tests, hormones and imaging used when investigating PMOS / PCOS (formerly PCOS), how to get tested, and how to read your results. It is not a standard prescription: the tests ordered depend on your situation, your symptoms, and the goals of your appointment. Your doctor decides.
A workup, not a checklist
There is no single standardised PCOS / PMOS panel applicable to all patients. Tests are selected according to the objective: confirming a diagnosis, assessing the metabolic dimension, planning a pregnancy, or monitoring skin symptoms. A workup may evolve from one appointment to the next, depending on what each result reveals.
This guide is intended to help you understand the vocabulary before your appointment, not to self-diagnose. To understand what each result means, see our interpretation guide.
Section 1 — Hormone tests
Hormones are central to PCOS / PMOS assessment. Several tests may be requested, not necessarily all at the same time.
Total and free testosterone
Testosterone is the androgen most commonly elevated in PCOS. Total testosterone is the most common test. Free testosterone (the biologically active fraction) is more informative but more complex to measure. An isolated elevated result is not sufficient to make the diagnosis — it must be interpreted in the clinical context.
SHBG (Sex Hormone Binding Globulin)
SHBG is a protein that transports sex hormones. A low SHBG level increases the free fraction of testosterone. In PCOS, SHBG is often low, partly because hyperinsulinaemia reduces its hepatic synthesis. It is an indirect marker of androgen excess.
DHEAS and androstenedione
DHEAS (dehydroepiandrosterone sulphate) is an androgen produced mainly by the adrenal glands. An elevated DHEAS can point toward an adrenal rather than ovarian origin of androgens. Androstenedione is produced by both the ovaries and adrenal glands; its measurement is sometimes requested to refine the androgenic profile.
LH and FSH
The gonadotrophins LH and FSH are ideally measured in the early follicular phase (D2–D5 of the cycle). In PCOS, the LH/FSH ratio is often elevated (LH disproportionately high relative to FSH), but this is not a sufficient diagnostic criterion on its own according to the 2023 international guideline.
AMH (anti-Müllerian hormone)
AMH is produced by developing ovarian follicles. It is often elevated in PCOS, reflecting the large number of small follicles. Some guidelines consider AMH as an alternative to ultrasound for the morphological criterion. It is not routinely requested — it is used depending on context (fertility follow-up, ovarian reserve, monitoring during treatment).
17-OH-progesterone, prolactin, TSH
These three tests serve mainly to exclude differential diagnoses(see Section 4). Prolactin can be elevated in PCOS, but a markedly high prolactin points to other causes. TSH rules out thyroid disease that can mimic or worsen PCOS. 17-OH-progesterone rules out non-classic congenital adrenal hyperplasia (CAH).
Section 2 — Metabolic tests
The metabolic dimension is inseparable from a complete PCOS / PMOS workup — it is the M in PMOS. The Monash 2023 guideline and the WHO both recommend regular metabolic screening.
Fasting glucose and HbA1c
Fasting glucose is the first indicator for evaluating glucose tolerance. HbA1c reflects average blood glucose over the past 3 months — it is more stable and less sensitive to single-point variations. Both are often ordered together. A fasting glucose between 5.6–6.9 mmol/L (100–125 mg/dL) indicates impaired fasting glucose without established diabetes.
Fasting insulin and HOMA-IR
Fasting insulin is not routinely prescribed in all countries. Combined with glucose, it allows calculation of the HOMA-IR score — an indicator of insulin resistance whose thresholds vary by laboratory and assay method. You can calculate your score with our cautious tool.
Lipid panel
A lipid panel includes total cholesterol, LDL cholesterol, HDL cholesterol, and triglycerides. In PCOS, the lipid profile is often abnormal: elevated LDL and triglycerides, low HDL. This profile contributes to long-term cardiovascular risk. Annual lipid monitoring is often recommended from diagnosis.
Blood pressure is measured at the appointment — not a blood test, but an important metabolic parameter to monitor in PCOS.
Section 3 — Imaging: pelvic ultrasound
Pelvic ultrasound is the reference imaging in PCOS assessment. It can be performed transvaginally (more accurate) or transabdominally depending on context and preference.
The morphological diagnostic criterion updated in 2023 is the presence of at least 20 follicles per ovary or an ovarian volume greater than 10 cm³ (without a follicular cyst or corpus luteum). This threshold was revised upward from the original Rotterdam criteria (12 follicles in 2003) to account for improvements in ultrasound technology.
Important note: not having many follicles on ultrasound does not exclude PCOS — and having them does not confirm it either. Ultrasound is one of three criteria (alongside clinical/biochemical hyperandrogenism and irregular cycles).
Section 4 — Differential diagnoses to exclude
Several conditions can present with symptoms similar to PCOS. Ruling them out is part of the diagnostic process:
- Thyroid disease — hypothyroidism can cause irregular cycles, weight gain, and fatigue. TSH is almost always requested.
- Hyperprolactinaemia — elevated prolactin can cause long or absent cycles. May result from a pituitary microadenoma or certain medications.
- Non-classic congenital adrenal hyperplasia (CAH) — a mild form of 21-hydroxylase deficiency. Screened for by measuring 17-OH-progesterone, ideally in the morning, fasting, during the early follicular phase.
- Cushing syndrome — hypercortisolism that can mimic PCOS (weight gain, hirsutism, irregular cycles). Considered when the clinical picture is particularly suggestive. Rarely the first hypothesis.
Section 5 — When to repeat testing?
Frequency depends on each patient's profile and clinical evolution. In practice:
- Metabolic tests (glucose, HbA1c, lipids): often annual or biannual, depending on risk profile. The Monash 2023 guideline recommends regular screening from diagnosis.
- Hormone tests: adapted to objectives — repeat if the situation changes (new treatment, fertility plans, different symptoms).
- Blood pressure and weight: at every appointment.
These frequencies are indicative. Your doctor will adapt them to your profile.
Frequently asked questions
Do I need to fast for all tests?
No, not all. Fasting glucose, fasting insulin, lipid panel and certain hormone tests (particularly testosterone) require an 8–12 hour fast. Others such as TSH or AMH can generally be done without fasting. Your doctor or laboratory will specify the conditions for each test prescribed.
When in my cycle should hormone tests be done?
For LH, FSH and oestradiol, testing is ideally done between day 2 and day 5 of the cycle (D2–D5) to measure baseline values in the early follicular phase. Testosterone can be tested at any time, as can prolactin, DHEAS, TSH and AMH. If you have amenorrhoea (no periods), your doctor will choose the timing based on context.
Will these tests be covered by my health insurance?
Coverage depends on your country, insurer, and the clinical indication. In the UK, tests prescribed by your GP or specialist within the NHS are generally covered. In the US, coverage depends on your insurance plan and whether PCOS is the documented indication. In many countries, standard hormone panels and metabolic tests are covered when prescribed by a physician for a recognised condition. Ask your doctor or lab about coverage before your tests.
Who can order these tests?
A GP (general practitioner) or primary care physician can order the vast majority: glucose, standard hormones, lipid panel, TSH, prolactin, and pelvic ultrasound. A gynaecologist, endocrinologist, or reproductive specialist may order additional tests depending on context. You do not necessarily need a specialist for a first-line workup.
How long are results valid?
There is no absolute rule. Hormonal values can vary with the cycle, stress, treatment, or weight changes. In practice, results more than 12 months old are often repeated if the clinical picture has changed. For metabolic tests (glucose, HbA1c, lipids), annual monitoring is often recommended. Your doctor will adjust frequency to your profile.
Do I need all these tests at once?
No. The workup is tailored to the goal of the appointment: initial diagnosis, metabolic assessment, fertility planning, or skin symptoms. It is common for testing to happen in stages, based on what each result reveals. No need to request everything at once — your doctor will prioritise based on clinical urgency.
Main sources
- NHS — Polycystic ovary syndrome (PCOS)
- NIH / NICHD — PCOS information
- International Evidence-based Guideline 2023 (Monash) — assessment, diagnostic criteria
- Mayo Clinic — PCOS: symptoms, causes and diagnosis
Page written from official public sources. It does not constitute a prescription or personalised medical advice. For any questions about your results, consult your doctor.