What blood tests help diagnose PCOS?

PCOS is diagnosed clinically (using the Rotterdam criteria: irregular ovulation, signs of excess androgens, and polycystic ovaries on ultrasound — two of three). Blood tests support it: androgens (total and free testosterone), LH and FSH, and crucially markers of insulin resistance — fasting insulin and glucose (HOMA-IR) and HbA1c. Thyroid and prolactin are checked to rule out mimics.

Why is insulin resistance important in PCOS?

Insulin resistance is a central driver in a majority of PCOS cases. High insulin stimulates the ovaries to produce more androgens, worsening PCOS symptoms, and raises the long-term risk of type 2 diabetes. This is why the WHO recommends evaluating for underlying insulin resistance, and why improving insulin sensitivity often improves PCOS symptoms.

Can you have PCOS with normal periods?

It's possible. PCOS is a spectrum, and some women have relatively regular cycles but still meet criteria through elevated androgens and polycystic ovaries, or show insulin resistance without classic symptoms. Because presentation varies and many cases go undiagnosed, testing the metabolic markers can reveal the insulin-resistance component even when cycles seem normal.

PCOS and Insulin Resistance: The Lab Connection

Polycystic ovary syndrome is one of the most common hormonal conditions in women — and one of the most misunderstood, because it’s often framed purely as a reproductive issue. Underneath, for most women who have it, sits a metabolic driver: insulin resistance. Understanding that connection changes how it’s tested and managed.

The stat most people don’t know

PCOS affects an estimated 10–13% of reproductive-aged women, and up to 70% of them remain undiagnosed worldwide (World Health Organization). That makes it both extremely common and massively under-recognized — a huge number of women have it without a name for what they’re experiencing.

The insulin connection

Here’s the key link: insulin resistance is a central feature in the majority of PCOS cases. When cells resist insulin, the body makes more of it — and high insulin stimulates the ovaries to produce more androgens (like testosterone), which drives the classic PCOS features: irregular cycles, acne, and unwanted hair growth. It’s a feedback loop, which is why the WHO recommends women newly diagnosed with PCOS be evaluated for insulin resistance, and why it raises long-term risk of type 2 diabetes.

The markers that reveal it

PCOS itself is diagnosed clinically (the Rotterdam criteria — irregular ovulation, excess androgens, polycystic ovaries; two of three). But blood work fills in the picture, especially the metabolic side:

Fasting insulin + glucose (HOMA-IR) — reveals the insulin-resistance driver, often before glucose is abnormal. (Fasting insulin, explained.)
HbA1c — screens for the elevated diabetes risk. (What HbA1c means.)
Total and free testosterone — the androgen excess.
LH, FSH, and (to rule out mimics) thyroid and prolactin.

Why the metabolic angle matters

Because insulin is upstream of the androgen problem, improving insulin sensitivity — through the same levers that help prediabetes: weight management, activity, reducing refined carbs, and sometimes medication — often improves PCOS symptoms and lowers the long-term metabolic risk. Tracking the insulin markers over time shows whether that’s working.

What this looks like in Bevita

Bevita's Overall picture screen showing HOMA-IR and metabolic markers with a plain-English insulin resistance flag

For PCOS, the insulin-resistance picture is the part a standard report leaves you to piece together. On this Bevita “Overall picture” screen, HOMA-IR (2.02) and beta-cell function are calculated and flagged for early insulin resistance — exactly the driver to track in PCOS. Bevita computes HOMA-IR from your fasting insulin and glucose, tracks it alongside your androgen and HbA1c results, and shows whether interventions are moving it — turning scattered results into the metabolic through-line.

What to do

If you suspect PCOS, ask for the metabolic panel too — fasting insulin/glucose and HbA1c, not just hormones.
Track the insulin markers — HOMA-IR shows the driver and whether it’s improving.
Target insulin sensitivity — it often improves symptoms and lowers diabetes risk together.
Work with a clinician — PCOS diagnosis and management should be individualized (Rotterdam criteria, ruling out mimics).

References

World Health Organization. Polycystic ovary syndrome.
Insulin resistance, metabolic syndrome and polycystic ovaries. Frontiers in Endocrinology.
Freeman AM, Acevedo LA, Pennings N. Insulin Resistance. StatPearls, NCBI.

This article is for education and isn’t medical advice. Discuss your results with a qualified clinician.

Track the PCOS metabolic picture with Bevita

The insulin-resistance side of PCOS is what a stack of lab PDFs makes hardest to see. Upload your labs to Bevita and it calculates HOMA-IR, tracks it alongside your androgen and blood-sugar markers, and flags whether the metabolic driver is improving. Download Bevita, upload your bloodwork, and see the connection behind PCOS.