Polycystic Ovary Syndrome (PCOS) is one of the most common hormonal disorders in women of reproductive age, yet it often takes years to get a diagnosis. The right lab tests can provide crucial answers and help you understand what's happening in your body.
What is PCOS?
PCOS is a hormonal condition that affects how your ovaries work. Despite its name, not everyone with PCOS has cysts on their ovaries. The syndrome is characterized by a combination of symptoms related to hormonal imbalance, including irregular periods, excess androgens (male hormones), and often insulin resistance.
PCOS affects approximately 1 in 10 women, but up to 70% remain undiagnosed. Many women spend years searching for answers before getting a proper diagnosis.
Common Symptoms of PCOS
- Irregular, infrequent, or absent periods
- Heavy bleeding when periods do occur
- Excess hair growth on face, chest, or back (hirsutism)
- Acne, especially along the jawline
- Hair thinning or male-pattern baldness
- Weight gain, particularly around the midsection
- Difficulty losing weight
- Darkening of skin in creases (acanthosis nigricans)
- Difficulty getting pregnant
- Mood changes, anxiety, or depression
The Rotterdam Criteria
PCOS is typically diagnosed when you have at least two of three criteria:
- Irregular ovulation - Irregular or absent periods
- Excess androgens - Elevated male hormones on blood tests OR physical signs like acne/excess hair
- Polycystic ovaries - Seen on ultrasound (12+ follicles per ovary)
Other conditions must be ruled out before diagnosis.
Essential Lab Tests for PCOS
Hormone Panel
Total and Free Testosterone
Elevated testosterone is a hallmark of PCOS. Free testosterone is often more sensitive for detecting excess androgens. Even mildly elevated levels can cause symptoms like acne and hirsutism.
DHEA-S (Dehydroepiandrosterone Sulfate)
Another androgen that's often elevated in PCOS. High levels help confirm androgen excess isn't coming from the adrenal glands alone.
Sex Hormone Binding Globulin (SHBG)
This protein binds to testosterone and other sex hormones. In PCOS, SHBG is often low, which means more free testosterone is available to cause symptoms. Low SHBG is also linked to insulin resistance.
LH and FSH
These hormones control your menstrual cycle. In PCOS, LH is often elevated while FSH is normal or low, creating an LH:FSH ratio greater than 2:1 (though this isn't required for diagnosis).
Estradiol
Estrogen levels help rule out other conditions and understand your overall hormonal picture.
Progesterone
Tested mid-luteal phase (about day 21) to confirm whether ovulation occurred. Low progesterone indicates anovulation, common in PCOS.
Metabolic Markers
Fasting Insulin
Up to 70% of women with PCOS have insulin resistance, even if they're not overweight. Elevated fasting insulin is a key indicator and drives many PCOS symptoms.
Fasting Glucose
Combined with insulin, this helps calculate insulin resistance markers like HOMA-IR.
Hemoglobin A1c
Shows your average blood sugar over 2-3 months and screens for prediabetes, which is more common in women with PCOS.
Lipid Panel
Women with PCOS often have elevated triglycerides and low HDL cholesterol, increasing cardiovascular risk.
Thyroid Function
TSH, Free T4, Free T3
Thyroid disorders can mimic PCOS symptoms and must be ruled out. Hypothyroidism can cause irregular periods, weight gain, and difficulty getting pregnant.
Additional Tests to Consider
AMH (Anti-Mullerian Hormone)
Often elevated in PCOS due to the increased number of small follicles in the ovaries. Can support diagnosis and fertility planning.
Prolactin
Rules out elevated prolactin as a cause of irregular periods.
17-Hydroxyprogesterone
Screens for non-classic congenital adrenal hyperplasia, which can look like PCOS.
When to Test
For the most accurate results:
- Day 2-5 of your cycle - Best for LH, FSH, estradiol, testosterone, DHEA-S, SHBG
- Day 21 (or 7 days before expected period) - Best for progesterone to confirm ovulation
- Fasting morning - Best for insulin, glucose, and lipids
- Any time - TSH, AMH, A1c (though morning is ideal)
If your periods are very irregular, your doctor may test at any time and interpret results accordingly.
Understanding Your Results
PCOS exists on a spectrum, and not every woman will have the same lab abnormalities. Common patterns include:
- Elevated testosterone with low SHBG
- LH higher than FSH (LH:FSH ratio > 2:1)
- Elevated fasting insulin
- Elevated AMH
- Low or absent mid-cycle progesterone rise
Taking Control of PCOS
Understanding your lab results is the first step toward managing PCOS. Treatment approaches may include:
- Lifestyle modifications (diet, exercise, stress management)
- Medications to regulate periods and reduce androgens
- Insulin-sensitizing medications if insulin resistance is present
- Fertility treatments if trying to conceive
- Nutritional supplements (inositol, vitamin D, omega-3s)
Get Answers About PCOS
Comprehensive hormone and metabolic testing can help you understand your PCOS and guide treatment. Build your custom panel today.
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