Perimenopause Lab Tests: What to Ask For and How to Interpret the Results

Why Your Doctor's Standard Panel May Not Be Telling You Much

The FSH and Estradiol Problem

FSH (follicle-stimulating hormone) is the most commonly ordered test to evaluate whether a woman is in perimenopause or menopause. The logic makes sense: as the ovaries become less responsive, the pituitary gland pumps out more FSH to try to stimulate them. A high FSH suggests declining ovarian function.

But in perimenopause, FSH levels can swing dramatically from week to week and even day to day. You might have a high FSH on the day you are tested and a completely normal FSH a week later. A single normal FSH result does not rule out perimenopause. A single high result does not confirm it.

Estradiol has the same problem. During perimenopause, estrogen is erratic. It surges and drops unpredictably. Testing on any given day gives you a snapshot of one point on a wildly variable curve. It is not a reliable baseline.

Current guidelines from the Menopause Society are explicit on this point: perimenopause is a clinical diagnosis based on symptoms and menstrual pattern in women over 40. Lab tests are supportive, not definitive. A doctor who says "your FSH is normal so you are not in perimenopause" is applying the test incorrectly.

Labs That Are Actually Worth Running

While FSH and estradiol are unreliable for diagnosing the transition, other labs can tell you a great deal about what is contributing to how you feel.

A full thyroid panel is essential. The standard TSH alone is not enough. Ask for TSH, free T4, and free T3. Thyroid dysfunction is two to eight times more common in women than men, often emerges or worsens in the perimenopausal years, and produces symptoms that overlap almost completely with perimenopause: fatigue, brain fog, mood changes, weight gain, constipation, dry skin. Treating a thyroid problem will not resolve perimenopause, but missing it means you are not getting the full picture.

Ferritin, not just a CBC (complete blood count), is worth testing. CBC measures red blood cell count and can catch overt anemia. Ferritin measures your iron stores and can be low even when your CBC looks fine. Low ferritin causes fatigue, brain fog, poor exercise tolerance, and hair loss, all symptoms commonly attributed to perimenopause. The lab normal range for ferritin extends down to 12 ng/mL at many labs, but many clinicians consider optimal levels to be at least 50 to 70 ng/mL for symptom resolution.

More Labs Worth Discussing

Vitamin D deficiency is extremely common and contributes to fatigue, mood instability, bone loss, and immune function. Ask for 25-hydroxyvitamin D. Lab normals call anything above 20 ng/mL sufficient. Most functional medicine practitioners and many endocrinologists consider 40 to 60 ng/mL to be a more optimal range for overall health.

Fasting insulin, alongside fasting glucose, gives you a more complete picture of metabolic health than glucose alone. Insulin resistance often worsens during perimenopause due to declining estrogen and its effects on insulin sensitivity. You can have normal fasting glucose and still have elevated fasting insulin, which signals early insulin resistance before diabetes develops.

DHEA-S is the sulfate form of DHEA, a precursor hormone produced mainly by the adrenal glands. It converts to estrogen and testosterone in peripheral tissues. DHEA-S declines steadily with age and declining levels are associated with fatigue, low libido, and reduced wellbeing. Low DHEA-S does not mean everyone needs supplementation, but it is useful context.

Testosterone (free and total) is worth testing if you are experiencing low libido, fatigue, or reduced drive, despite otherwise adequate sleep and mood management. Female testosterone levels are 10 to 15 times lower than male levels, and the reference ranges on standard lab panels are often so broad they are nearly meaningless. A knowledgeable provider will help interpret your level in context.

Understanding Lab Normal vs. Optimal

Lab reference ranges are built from population data. They represent the range in which 95 percent of tested individuals fall. By definition, some people feel terrible within the reference range and would feel much better at a different level within that range.

This gap between "normal" and "optimal" is especially relevant for ferritin, vitamin D, and thyroid hormones. A ferritin of 13 ng/mL is technically normal at most labs. But many women at that level experience significant fatigue and hair loss that resolves when ferritin is raised to 60 or 70 ng/mL. The lab will not flag that 13 as a problem.

For thyroid hormones, the TSH reference range is typically 0.5 to 4.5 mIU/L at most labs. But some research, and many experienced clinicians, consider a TSH above 2 to 2.5 mIU/L to be suboptimal in symptomatic women, particularly when free T3 is on the lower end of the normal range.

None of this means you should chase numbers obsessively or demand treatment you do not need. It means understanding that a result described as normal does not automatically mean it is optimal for you specifically.

What to Ask for and How to Frame the Request

Asking for labs can feel awkward, especially if you are worried about being seen as demanding or self-diagnosing. A useful framing is to focus on symptoms rather than conditions. You are not asking your doctor to test for menopause. You are asking to evaluate the possible contributors to specific symptoms.

A practical approach: write down your symptoms, duration, and severity before your appointment. Then say something like: "I have been dealing with significant fatigue, brain fog, and hair changes. I would like to make sure we rule out thyroid issues, low ferritin, and vitamin D deficiency as contributing factors. Can we add those to my labs?"

If you are experiencing low libido or reduced drive, you can ask for testosterone levels to be included. If you have metabolic concerns or family history of diabetes, ask for fasting insulin alongside fasting glucose.

You may encounter resistance. Some providers order the minimum panel they believe is clinically indicated. If you are not getting the workup you feel you need, it is reasonable to advocate for yourself or seek a provider who practices more comprehensive evaluation.

Direct Lab Testing: An Option When Your Doctor Won't Order What You Need

When to Retest and What to Track Over Time

A single set of labs is a point-in-time snapshot. For conditions that change, following values over time gives more useful information than any one result.

If you start a vitamin D supplement, retest in three months to see whether your level has responded adequately to your dose. If you address low ferritin with diet or supplementation, retest after three months. Thyroid function should be rechecked after any change in thyroid medication and then annually.

For hormone markers like testosterone and DHEA-S, if they are tested as part of considering a treatment, retesting after a treatment trial at a consistent time of day gives the most interpretable comparison.

Tracking symptoms alongside labs helps you and your provider connect changes in how you feel to changes in your labs. If your ferritin goes from 15 to 65 ng/mL and your fatigue significantly improves, that is meaningful clinical data. If it does not improve much, you know the fatigue has other contributors to explore.

Building a More Informed Conversation with Your Provider

The goal of knowing about labs is not to become your own doctor. It is to be a better participant in your own care. When you understand what tests measure and why they matter, you can ask more specific questions and make better use of your appointment time.

Write your questions down before you go. Bring your symptom history. Ask specifically about the tests described here and why each one is or is not relevant to your situation. A provider who is confident in their approach will explain their reasoning. One who becomes defensive may not be the right fit.

Good perimenopause care involves treating symptoms, not just normalizing numbers. But having the right numbers in front of you gives you and your provider the complete picture needed to do that well.

Other Labs That Come Up in Perimenopause Care

A few additional tests appear frequently in conversations about perimenopause and are worth understanding.

HbA1c (glycated hemoglobin) measures your average blood sugar over the past two to three months. It is the primary screening tool for diabetes and prediabetes. Because insulin resistance worsens during perimenopause, screening at this stage is clinically sensible, especially with a family history of metabolic disease or unexplained weight gain around the midsection.

Cortisol testing is sometimes ordered, though interpretation is complex. Cortisol is a stress hormone that fluctuates significantly throughout the day and is highly sensitive to the stress of the blood draw itself. A simple morning cortisol can screen for severely abnormal adrenal function, but it does not meaningfully measure chronic stress response or adrenal fatigue, a concept that lacks clinical validation despite its popularity in wellness contexts.

CA-125 is sometimes discussed in the context of ovarian health. It is not a reliable screening tool for ovarian cancer in average-risk women and is not part of standard perimenopause evaluation. If you are having symptoms that concern you about ovarian health, a conversation with your provider about what evaluation is appropriate is more useful than requesting this test independently.

Homocysteine and inflammatory markers like hsCRP may be relevant for women with cardiovascular risk factors. Elevated homocysteine is associated with B vitamin deficiency as well as cardiovascular risk. If you have a personal or family history of heart disease, asking about these alongside standard lipids gives a more complete cardiovascular picture.

Putting It Together: A Practical Lab Request List

If you are going into an appointment specifically to investigate perimenopausal symptoms and their contributors, here is a practical list of what to discuss requesting.

Thyroid panel: TSH, free T4, free T3, and ideally thyroid peroxidase antibodies if thyroid autoimmune disease runs in your family. Ferritin: separate from the CBC, specifically ferritin as a standalone test. Vitamin D: 25-hydroxyvitamin D. Fasting metabolic panel: fasting glucose and fasting insulin together. Lipid panel: total cholesterol, LDL, HDL, triglycerides. DHEA-S and testosterone (free and total) if you have low libido, fatigue, or reduced drive.

You do not need to request all of these at every appointment. But at an initial comprehensive perimenopause evaluation, these together provide a much more actionable picture than FSH and estradiol alone.

Bring this list to your appointment as a discussion starting point, not as a demand. Explain what symptoms you are trying to understand and why each test seems relevant. Your provider may have clinical reasons to prioritize differently, and that conversation is worth having.

Disclaimer

This content is for informational purposes only and does not replace medical advice. Always consult your healthcare provider about your specific situation.