How to Diagnose PCOS: A Doctor Explains Tests & Signs

In everyday clinical practice across India, I meet women who already suspect they may have PCOS—thanks to the awareness created on social media, health influencers, and trending conversations.

While that awareness is helpful, it’s also important to understand how PCOS is actually diagnosed, especially when the symptoms seem vague or overlapping.

Let me walk you through what I, as a gynecologist, do in the clinic—what we look for, what tests matter, and when it’s worth going deeper.

Often, women come across the term PCOS during a routine health check-up, especially when ultrasound reports mention “PCOS-like appearance.” This can lead to confusion: “Do I really have PCOS, or is it just a scan finding?”

That’s where clinical history and relevant blood tests come in to guide us toward a correct diagnosis.

Step 1: Clinical History—What We Ask & Why It Matters

We always begin with your story. Your symptoms give us the first set of clues. Some of the most common indicators we look for:

• Irregular or delayed periods
  
• Weight gain (especially in the lower abdomen or thighs)
  
• Unwanted facial or body hair (hirsutism)
  
• Acne or oily skin
  
• Mood swings, anxiety, or emotional fluctuations
  
• Infertility or difficulty conceiving
  

This history gives us a functional view of how your hormones are behaving.

Step 2: Blood Tests That Actually Matter

Let me clear one thing upfront—not every test marketed as a “PCOS profile” is clinically useful. Here’s what we really need:

1. Anti-Müllerian Hormone (AMH)

Especially in “lean PCOS” (where weight is normal), AMH levels are often elevated.

• A value above 9 ng/ml is highly suspicious of PCOS.
• High AMH reflects difficulty in follicle maturation due to excess androgens, leading to multiple small follicles.

2. TSH & Prolactin

These help us rule out thyroid dysfunction or prolactin-related cycle issues, both of which can mimic PCOS symptoms.

What We Don’t Rely on Anymore

• FSH/LH Ratio

This was once used widely. A typical LH-to-FSH ratio greater than 2:1 is commonly seen in PCOS and can be a strong indicator of the condition. However, this test has slowly vaned off due to a lot of women not correlating (inconsistent results)

• Fasting Insulin Levels

Although insulin resistance is central to PCOS, measuring fasting insulin is no longer considered a practical or useful diagnostic tool.

When Androgens Need Closer Attention?

Some women with PCOS have signs of androgen excess, like excessive hair growth or acne. In these cases, we may evaluate:

• Total & Free Testosterone
  
• Serum DHEA-S (only if we suspect adrenal origin of symptoms)
  

These are useful when we’re ruling out other causes of hirsutism or androgen excess, not routine for all PCOS patients.

Step 3: Ultrasound Findings

The classic image of “multiple small follicles arranged in a ring-like pattern” or “string of pearls” in the ovary gives us a strong visual clue.

But remember: having PCOS-like ovaries on ultrasound doesn’t confirm PCOS on its own. That’s why we correlate it with history and blood tests.

The Most Important Step: Clinical Judgment

I can’t stress this enough—lab values and reports can only go so far.
A thorough clinical evaluation by a PCOS specialist is the most valuable step in your diagnostic journey.

Most cases can be diagnosed with just your history, a few key tests, and a good ultrasound. Only treatment-resistant or atypical PCOS needs deeper investigation.

Confused about your test results or PCOS diagnosis? Book a consultation with Dr. Jay Mehta, PCOS specialist and fertility expert in Mumbai.  We’ll help you get clarity, without unnecessary tests or panic.