If you’ve been diagnosed with PCOS, one of the first things your doctor will recommend is a blood test. Often, this includes a full panel of blood tests (WHO, 2025), checking your hormones, blood sugar levels, and other key metabolic markers. But with so many hormones and markers being checked, it can feel overwhelming.
In this blog, we’ll break down which tests to get done, which hormones and markers to check, what your results actually mean, and how testing can help you feel more in control of your health.
1. Why Blood Tests Are Key to Understanding Your PCOS Type
PCOS is a complex hormonal condition that affects up to 1 in 5 women of reproductive age (PMC, 2019) in India. But it doesn’t look the same for everyone. It can show up as
- Irregular or missed periods
- Sudden, unexplained weight gain
- High blood sugar levels
- Hormonal ance & excess facial hair (Hirsutism)
- Difficulty getting pregnant
(A) What Blood Tests Can Tell You
PCOS is a syndrome, not a disease. That means it involves a collection of signs and symptoms, and no one test can confirm it (Escobar-Morreale, 2018).
Blood tests help identify your “type” of PCOS, whether it’s driven more by insulin, androgens, or hormone imbalances. They also help:
- Confirm a diagnosis,
- Pinpoint your PCOS type (hormonal, metabolic, or both),
- Rule out similar conditions (like thyroid disorders or high prolactin),
- Check cholesterol and inflammation levels
That’s why the right blood tests matter. Blood tests take the guesswork out of PCOS, and are essential to understanding what’s really going on inside your body, and guide you towards treating the root cause & not just symptoms.
2. What Key Hormones Are Tested for Diagnosing PCOS?
Let’s walk through the most commonly tested hormones (Dason et al., 2024) and markers, and why they matter for PCOS.
(B) LH (Luteinizing Hormone) & FSH (Follicle Stimulating Hormone)
These hormones regulate your menstrual cycle, and trigger ovulation (the release of an egg).
In women with PCOS, doctors often look at the LH:FSH ratio.
- In a healthy cycle: LH and FSH are usually in a 1:1 balance
- In PCOS: The LH level is often much higher than FSH, often greater than 2:1 (Williams et al., 2023). This imbalance can prevent an egg from maturing and being released
What it shows:
A high LH:FSH ratio can disrupt ovulation (Malini et al., 2018), disrupting you menstrual cycles. This can lead to irregular or absent periods, along with other symptoms like hormonal acne, bloating, weight changes, low energy, & mood swings
(C) AMH (Anti Müllerian Hormone)
AMH is a hormone released by tiny sacs in the ovaries called follicles, which hold immature eggs. In a normal cycle, one follicle grows large enough to release its egg during ovulation.
In women with PCOS, many follicles start developing at the same time but none fully mature. These undeveloped follicles remain in the ovary as small fluid-filled sacs, which are called “cysts.” Having many of these gives the ovaries their “polycystic” appearance on an ultrasound.
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Why it matters: AMH reflects your ovarian reserve, which is the number of eggs left in your ovaries
- Normal AMH: 1–4 ng/mL
- In PCOS: Often above 5–6 ng/mL (PMC, 2021)
(D) Total Testosterone and Free Testosterone Test
A type of androgen, or “male hormone”, produced in women by the ovaries and adrenal glands in small amounts, supporting bone strength, muscle health, mood, and sex drive.
- What Does This Test Measure? This test measures total and free testosterone levels in your blood to check for elevated androgens, which are common in women with PCOS (Kanbour et al., 2022)
- What it shows: High testosterone levels makes it harder for the body to control blood sugar levels, contributing to weight gain, especially around the belly, & worsening of PCOS symptoms like chin & jawline acne, hair thinning, and excessive facial or body hair (hirsutism) (Ashraf et al., 2019)
(E) DHEAS (Dehydroepiandrosterone sulfate)
- Why it matters: Another androgen, produced by your adrenal glands, that helps the body make estrogen and testosterone, supporting menstrual cycle regularity, energy levels, and hormone balance
- What it shows: If your DHEA-S is elevated, it may mean your adrenals are also contributing to excess androgens (male hormones), which can worsen PCOS symptoms (Mallya et al., 2024)
Testing DHEA-S helps your doctor figure out whether the excess androgens are coming from the ovaries, the adrenal glands, or both.
3. Why Insulin and Blood Sugar Tests Are Key for Understanding PCOS
Up to 70% of women with PCOS have insulin resistance (Zhao et al., 2023), meaning their cells don’t respond well to insulin, the hormone responsible for moving sugar from the blood into cells for energy.
When this happens, sugar builds up in the blood, so the body produces more insulin to lower blood sugar provide energy to cells
Over time, this extra insulin can:
- Disrupt your metabolism, making it harder to burn fat efficiently
- Increase the risk of pre-diabetes and type 2 diabetes
- Trigger hormonal imbalances that worsen PCOS symptoms
(A) Key Tests for Insulin Resistance in PCOS
Doctors usually check fasting insulin and/or HOMA-IR because they give an insight into how well your body responds to insulin
- Fasting Insulin measures insulin in your blood after 8–12 hours without food to get an accurate baseline, since eating can temporarily raise insulin.
- It helps detect insulin resistance, which is closely linked to PCOS symptoms like (Amisa, 2022):
- Belly fat
- Sugar cravings
- Irregular ovulation
- HOMA-IR uses your fasting blood sugar and insulin levels to estimate how well your body uses insulin and controls blood sugar (M Chappell, 2019)
Higher scores mean your body is struggling to regulate blood sugar effectively.
Why it matters: High insulin can trigger more androgen production and worsen symptoms like weight gain, acne, and missed periods.
(B) Fasting Glucose & HbA1c Tests: What They Tell You About Blood Sugar
Alongside insulin tests, these two tests show how well your body metabolises sugar over time
- Fasting Glucose measures your blood sugar after 8–12 hours of not eating.
- HbA1c (Glycated Hemoglobin) gives a 2–3 month average of your blood sugar levels.
Why it matters for PCOS: Even mild blood sugar issues can keep insulin levels high, worsening PCOS symptoms, and making weight management harder. Detecting these changes early means you can improve insulin sensitivity, balance hormones, and protect long-term health.
4. Should You Get Tested for Thyroid or Prolactin if You Have PCOS?
Yes, always.
High prolactin or thyroid imbalances (K. Nath et al., 2019) (especially hypothyroidism) can cause similar symptoms to PCOS, like irregular periods, fatigue, weight gain, & mood swings.
Your thyroid controls how fast your body uses energy, influencing metabolism, menstrual cycles, mood, digestion, and even hair growth.
Prolactin is a hormone that helps prepare the body for breastfeeding after pregnancy and also regulates hormones, supports reproductive health, and influences mood in non-pregnant women.
(A) Thyroid Hormone Tests to Get: TSH, T3, T4
Low thyroid function (hypothyroidism) shares symptoms with PCOS, such as:
- Irregular or heavy periods
- Weight gain
- Fatigue
- Hair thinning
Why it matters for PCOS:
Hypothyroidism slows metabolism, disrupts periods, and causes weight gain, mimicking PCOS symptoms. Testing helps avoid misdiagnosis and ensures proper treatment. (PMC, 2019)
(B) Prolactin - Helping Rule Out Other Hormonal Imbalances
Around 15–20% of women with PCOS have mildly elevated prolactin due to hormonal imbalances, stress, or chronic an-ovulation (NIH, 2023)
In non-pregnant women, high levels (hyperprolactinemia) can stop ovulation and mimic PCOS symptoms like:
- Irregular cycles
- Hormonal Acne
- Infertility
- Mood changes
Why it matters for PCOS:
Testing helps determine whether your symptoms are due to PCOS or if another condition needs attention.
5. How to Understand Your PCOS Blood Test Results
By now, you know what each test is for, but what do the numbers actually mean for you?
Here’s a simplified breakdown of what high or low results results may indicate:
Expert insight:
“Blood test results are just one part of your PCOS diagnosis. Every person is unique, and labs can vary. Always discuss your results with your healthcare provider, who can tailor treatment based on your overall health and goals.”
— Dr. Akansha Batra, OB/GYN
Important: These patterns are not a final diagnosis. Your doctor will interpret them alongside your symptoms, cycle history, and (sometimes) ultrasound findings to create the full picture.
6. Complete PCOS Blood Test Checklist: Key Hormones and Metabolic Markers to Check
Here’s a quick recap of list of key hormone and metabolic markers to discuss with your doctor or take to your next lab visit.
Hormonal Tests:
- LH & FSH
- AMH
- Total & Free Testosterone
- DHEA-S
- Free Androgen Index (FAI)
- TSH, Free T3, Free T4
- Prolactin
Metabolic Tests:
- Fasting Insulin
- HOMA-IR
- Fasting Blood Glucose
- HbA1c
Tip: Always get your tests done early in your cycle (day 2–5 of your period), unless advised otherwise by your doctor.
7. Most Asked Questions About PCOS Blood Tests
Q: Do I still have PCOS even if my blood tests come back normal?
Yes. PCOS is diagnosed through a combination of symptoms, ultrasound, and lab tests, not just a single marker. It's possible to meet clinical criteria even when hormone levels are within normal ranges. (NHS, 2022)
Q: When is the best day of my menstrual cycle to get PCOS blood tests?
Day 2–5 of your period is ideal for checking LH, FSH, and testosterone. If cycles are irregular or absent, tests can be done anytime.
Q: What tests help rule out other conditions that look like PCOS?
Doctors may recommend thyroid tests (TSH, T3, T4), prolactin, and sometimes 17-hydroxyprogesterone to check for thyroid disorders, hyperprolactinemia, or adrenal issues. (E. Joham et al., 2025)
Q: Are ultrasound or pelvic exams necessary for PCOS, apart from blood tests?
Not always, but they can help confirm PCOS diagnosis. Ultrasound can show multiple small follicles (“polycystic ovaries”), but PCOS can be diagnosed without it if other criterias are met.
8. The Bottom Line
Blood tests are an essential part of understanding your PCOS, not just diagnosing it. They help identify what kind of hormonal and metabolic imbalances you’re dealing with, so your treatment can be more precise and effective.
And while those lab reports can look like alphabet soup, they’re really just signals your body is sending, telling you what it needs.
Wondering what your blood test results mean, or how to get started? Our PCOS experts and doctors are here to help you understand your results and take action that works for you.