PCOS Blood Tests: Why "Normal" Results Don't Always Mean You're Fine

"Your bloods are normal." If I had a pound for every woman who has told me that's what her GP said, I'd have a very nice holiday fund. And yet she's sitting in front of me with irregular periods, weight that won't shift, sugar cravings at 3pm and hair thinning on her head. So what's going on?

In this article I'll explain which blood tests matter for PCOS, why "normal" doesn't always mean optimal, and what to ask your GP for.

Why "normal" results can still miss PCOS

Lab reference ranges are built from a large general population. They're designed to flag disease, such as type 2 diabetes, not the early hormonal and metabolic changes that drive PCOS symptoms.

Insulin resistance is a good example. It affects most women with PCOS, including many who are a healthy weight. Your body can keep your blood sugar (and your HbA1c) looking perfectly normal for years by producing more and more insulin. That extra insulin tells your ovaries to make more testosterone, makes you hungrier and makes it easier to store fat around your middle. But if nobody tests your insulin, nobody sees it.

The same happens with hormones. Your total testosterone can sit inside the normal range while your SHBG (the protein that carries testosterone around) is low. Low SHBG means more free, active testosterone, which is what causes acne, extra hair and missing periods.

One of my clients put it perfectly: "When I looked at the blood test, everything was saying normal and I was thinking, what is wrong then?" Once we looked at her results together, it finally made sense.

The blood tests I look at for PCOS

Hormones

• Total testosterone and SHBG, so the free androgen index can be worked out.
• LH and FSH. If you have periods, these are best taken on day 2–5 of your cycle.
• AMH. Since the 2023 international PCOS guideline, AMH can be used in adults instead of an ultrasound to show polycystic ovaries.
• Prolactin, thyroid (TSH) and 17-OH progesterone. These help rule out other conditions that look like PCOS.

Metabolic health

• Fasting glucose and HbA1c. Every woman with PCOS should have her blood sugar checked.
• Fasting insulin. This isn't routinely offered on the NHS, but it can be done privately and tells us a lot about insulin resistance.
• Cholesterol and triglycerides (lipid profile). High triglycerides often go hand in hand with insulin resistance.

Nutrients

• Vitamin D. Low levels are very common in the UK, especially in winter.
• Ferritin (iron stores). Important if your periods are heavy, or if you feel exhausted.
• Vitamin B12. Especially if you take metformin, which can lower B12 over time.

How to ask your GP

Your GP will usually check the basics, such as testosterone, SHBG, LH, FSH, glucose and HbA1c. You can ask politely about the others, explaining your symptoms. Write them down before your appointment, because it's easy to forget in the room. If some tests aren't available on the NHS, a private blood test is an option.

And remember: blood tests are only one part of the picture. Your symptoms, your cycle and your history matter just as much.

What I do with your results

In the first week of my PCOS Elevate programme, I go through every one of your blood results with you, and you get a written report. You'll understand why your results look the way they do and what's driving your symptoms. Then we build your nutrition, movement, stress and supplement plan around them, so you're not guessing anymore.

If you've been told your bloods are "normal" but you don't feel normal, book a free discovery call and we'll talk it through.

This article is for general education and isn't a substitute for personal medical advice. Always speak to your GP about tests and treatment.