Hormone Blood Tests Explained: What Your Labs Actually Mean

You got your lab results back. There's a column of abbreviations, a column of numbers, and a reference range that's supposed to tell you whether things are normal. But "normal" doesn't feel very informative when you're trying to understand what's actually going on with your body.

Hormone blood tests are among the most commonly ordered labs in medicine — and among the most poorly explained. Here's what each test measures, why it matters, and how to make sense of your results.

Testosterone Panel

Total Testosterone

What it measures: The total amount of testosterone in your blood — including testosterone that's bound to proteins (SHBG and albumin) and testosterone that's free-floating.

Normal ranges:

• Men: approximately 300-1000 ng/dL (varies by lab)
• Women: approximately 15-70 ng/dL

What to know: Total testosterone is the standard screening test, but it doesn't tell the whole story. A significant portion of your total testosterone is bound to SHBG and isn't biologically active. Two people with the same total testosterone can have very different amounts of usable hormone depending on their SHBG levels.

Levels fluctuate throughout the day — they peak in the early morning and drop by afternoon. This is why testosterone should be drawn between 7 and 10 AM for the most accurate result.

Free Testosterone

What it measures: The fraction of testosterone that's not bound to any protein — the portion that's immediately available to your cells.

Normal ranges:

• Men: approximately 5-21 pg/mL (or 1-3% of total)
• Women: approximately 0.3-1.9 pg/mL

What to know: Free testosterone often provides a better picture of what's actually happening at the tissue level. Some men have a normal total testosterone but low free testosterone because their SHBG is high — and they experience symptoms of low T despite "normal" total levels. If your physician only checked total testosterone and your symptoms don't match the number, ask about free testosterone.

SHBG (Sex Hormone-Binding Globulin)

What it measures: A protein produced by the liver that binds testosterone (and estrogen), making it biologically inactive.

Normal ranges:

• Men: approximately 10-57 nmol/L
• Women: approximately 18-144 nmol/L

What to know: High SHBG means more of your testosterone is bound and unavailable. SHBG increases with age, thyroid excess, liver disease, and estrogen exposure (including oral contraceptives). Low SHBG is associated with obesity, insulin resistance, and hypothyroidism. SHBG is the key to understanding the gap between total testosterone and how you actually feel.

Estrogen Panel

Estradiol (E2)

What it measures: The most potent and clinically relevant form of estrogen. In premenopausal women, it's produced primarily by the ovaries. In men, it's produced through aromatization of testosterone.

Normal ranges (vary by context):

• Premenopausal women: 30-400 pg/mL (fluctuates dramatically with the menstrual cycle)
• Postmenopausal women: less than 30 pg/mL
• Men: 10-40 pg/mL

What to know: In women, estradiol levels during menopause confirm the hormonal transition and help guide HRT dosing. In men, estradiol is relevant because elevated levels — often from increased aromatase activity due to excess body fat — can cause gynecomastia, mood changes, and water retention. Men on testosterone therapy should have estradiol monitored to ensure it doesn't rise excessively.

Progesterone

What it measures: Progesterone produced by the corpus luteum after ovulation (in premenopausal women) or by the adrenal glands in small amounts.

Normal ranges:

• Follicular phase: less than 1 ng/mL
• Mid-luteal phase: 5-20 ng/mL
• Postmenopausal: less than 1 ng/mL

What to know: Timing is critical. Progesterone should be measured during the mid-luteal phase (days 19-21 of a standard 28-day cycle). A mid-luteal progesterone below 3 ng/mL suggests anovulation — you had a period but didn't ovulate, which means progesterone wasn't produced in adequate amounts. This is extremely common in perimenopause and is a key contributor to symptoms often attributed to estrogen.

Thyroid Panel

TSH (Thyroid-Stimulating Hormone)

What it measures: A pituitary hormone that controls how hard your thyroid works. Think of it as the thermostat for thyroid function.

Normal range: 0.4-4.5 mIU/L (though the functional range many clinicians target is 0.5-2.5)

What to know: TSH is inversely related to thyroid function. High TSH means your thyroid is underactive (hypothyroidism) — the pituitary is shouting louder to get the thyroid to work harder. Low TSH means your thyroid is overactive (hyperthyroidism). TSH is the best initial screening test for thyroid disorders but shouldn't be the only test if symptoms are present.

Free T4 (Thyroxine) and Free T3 (Triiodothyronine)

What they measure: The two active thyroid hormones. T4 is the more abundant form; T3 is the more potent form. Your body converts T4 to T3 in peripheral tissues.

Normal ranges:

• Free T4: 0.8-1.8 ng/dL
• Free T3: 2.3-4.2 pg/mL

What to know: Some patients have a normal TSH but low-normal T3, and they still experience hypothyroid symptoms. This can indicate a conversion issue — the body isn't efficiently turning T4 into the active T3 form. Checking both gives a more complete picture.

Thyroid Antibodies (TPO, Thyroglobulin)

What they measure: Antibodies that target your thyroid gland, indicating autoimmune thyroid disease (Hashimoto's thyroiditis or Graves' disease).

What to know: Positive thyroid antibodies with a normal TSH means you may have early autoimmune thyroid disease that hasn't yet caused measurable dysfunction. These patients are at higher risk of developing overt hypothyroidism over time and may benefit from monitoring.

Other Hormones Worth Knowing

LH (Luteinizing Hormone) and FSH (Follicle-Stimulating Hormone)

These pituitary hormones regulate the ovaries and testes. In the context of hormone testing:

• Elevated FSH in women suggests diminished ovarian reserve or menopause
• Low LH and FSH in men with low testosterone suggests a pituitary cause (secondary hypogonadism) rather than a testicular one
• LH/FSH ratio can be informative in diagnosing PCOS in women

DHEA-S (Dehydroepiandrosterone Sulfate)

An adrenal hormone that serves as a precursor to both testosterone and estrogen. DHEA-S declines with age and is sometimes checked as part of a comprehensive hormone assessment, particularly in women with fatigue, low libido, or adrenal concerns.

Prolactin

A pituitary hormone that can suppress testosterone and estrogen production when elevated. High prolactin in men or non-pregnant, non-lactating women warrants further investigation — it can indicate a pituitary adenoma or be caused by certain medications.

How to Get the Most From Your Lab Results

Get tested at the right time. Testosterone: early morning, fasting. Progesterone: mid-luteal phase. Random testing can produce misleading numbers.

Look at patterns, not single numbers. A single lab draw is a snapshot. Trends over time are more informative. If a value is borderline, repeat it before drawing conclusions.

Consider symptoms alongside numbers. A testosterone of 320 ng/dL is technically "normal" — but if it comes with fatigue, low libido, and brain fog, it may still warrant treatment. Ranges are statistical constructs, not clinical absolutes.

Ask for a copy of your results. You have the right to your own lab data. Having it allows you to track changes, get second opinions, and understand your health more completely.

The Bottom Line

Hormone labs don't have to be confusing. When you understand what each test measures and how the numbers relate to each other, you can have a much more informed conversation with your physician about what's going on and what to do about it.

If you'd like a comprehensive hormone evaluation — with a physician who'll actually explain your results — Coral Health can help. We order the right tests, interpret them in context, and build a plan that makes sense for your specific situation.