10 Blood Values Every Man Over 30 Should Know

An annual blood panel is not part of the standard routine for many men — even though it is one of the most effective preventive health measures. From age 30 onwards, numerous physiological changes begin: testosterone levels decline by approximately 1–2% per year, metabolism slows, and the risk of metabolic and cardiovascular disease increases.

The problem: many of these changes progress gradually and without obvious symptoms — until a critical threshold is reached. A targeted blood panel can detect subclinical changes early, before they become genuine health problems.

This guide explains the 10 most important blood values for men over 30 — what they measure, what the reference ranges are, and when you should take action.

1. Total Testosterone

What it measures: The total amount of testosterone in the blood — both bound and free. Testosterone is the central androgen and influences muscle mass, libido, mood, energy levels, and cognitive function.

Reference range: 10.4–34.7 nmol/L (Endocrine Society). From age 30, levels decline by approximately 1–2% per year (Travison et al., 2007).

When to act: Values below 12 nmol/L combined with symptoms (fatigue, loss of libido, difficulty concentrating) warrant further investigation. Detailed information is available in our article about testosterone after 30.

2. Free Testosterone

What it measures: The biologically active fraction of testosterone — only 1–3% of the total, but the clinically decisive value. Total testosterone can be normal while free testosterone is low — particularly when SHBG is elevated.

Reference range: 220–700 pmol/L (age-dependent). Detailed reference tables are available in our article on free vs. total testosterone.

When to act: A calculated free testosterone below 220 pmol/L with matching symptoms indicates treatable hypogonadism according to the European Male Ageing Study (EMAS) (Wu et al., 2010).

3. SHBG (Sex Hormone-Binding Globulin)

What it measures: The amount of the transport protein that binds testosterone in the blood and thereby inactivates it. SHBG is the decisive factor in the ratio between total and free testosterone.

Reference range: 20–50 nmol/L.

When to act: Elevated SHBG (above 50 nmol/L) can lead to functional testosterone deficiency despite normal total testosterone. Causes include age, hyperthyroidism, liver disease, and certain medications. Low SHBG (below 20 nmol/L) occurs with obesity, insulin resistance, and diabetes.

4. LH and FSH (Gonadotropins)

What they measure: LH (luteinising hormone) and FSH (follicle-stimulating hormone) are pituitary hormones that control testicular function. They distinguish between primary hypogonadism (testes produce insufficient testosterone, LH/FSH elevated) and secondary hypogonadism (pituitary sends insufficient signal, LH/FSH normal or low).

Reference range: LH: 1.5–9.3 IU/L; FSH: 1.4–18.1 IU/L.

When to act: Low testosterone + low LH suggests secondary hypogonadism requiring further diagnostic investigation. Low testosterone + high LH confirms primary hypogonadism. Both forms are medically treatable — your physician at Swiss TRT evaluates the constellation in the overall context.

5. Haematocrit and Haemoglobin

What they measure: Haematocrit (proportion of red blood cells in blood volume) and haemoglobin (oxygen transport protein). Under TRT, haematocrit typically rises — this is the most common side effect and requires regular monitoring.

Reference range: Haematocrit: 38–52%; Haemoglobin: 13.5–17.5 g/dL.

When to act: A haematocrit above 54% during TRT requires dose adjustment or therapy pause. Elevated values without TRT may indicate dehydration, sleep apnoea, or chronic lung disease. This value is routinely checked at every TRT follow-up.

6. PSA (Prostate-Specific Antigen)

What it measures: A protein produced by the prostate. Elevated PSA values can indicate various prostate conditions — from benign enlargement (BPH) to prostate cancer. PSA is an important screening value during TRT, although the TRAVERSE study showed no increased prostate cancer risk with TRT.

Reference range: Below 4.0 ng/mL (age-dependent; for men under 50, below 2.5 ng/mL recommended).

When to act: A PSA increase of more than 1.4 ng/mL within 12 months or an absolute value above 4.0 ng/mL requires urological investigation — regardless of whether TRT is in place. A baseline PSA before starting TRT is mandatory.

7. HbA1c (Long-Term Blood Sugar)

What it measures: The average blood sugar level over the past 2–3 months. HbA1c is the most reliable marker for metabolic health and an early indicator of insulin resistance and type 2 diabetes — both risk factors for low testosterone.

Reference range: Below 5.7% (normal); 5.7–6.4% (prediabetes); above 6.5% (diabetes).

When to act: Values in the prediabetic range are a warning signal and an important reason to optimise diet, exercise, and body weight. Insulin resistance lowers SHBG and affects testosterone production — the topics are directly linked.

8. Lipid Profile (Cholesterol)

What it measures: LDL cholesterol ("bad"), HDL cholesterol ("good"), total cholesterol, and triglycerides. The lipid profile is a central marker for cardiovascular risk.

Reference range: Total cholesterol: below 5.2 mmol/L; LDL: below 3.4 mmol/L; HDL: above 1.0 mmol/L; Triglycerides: below 1.7 mmol/L.

When to act: Elevated LDL or triglycerides combined with low HDL significantly increase cardiovascular risk. Low testosterone levels are associated with less favourable lipid profiles — TRT can have a positive influence here (Bhasin et al., 2018).

9. TSH (Thyroid)

What it measures: TSH (thyroid-stimulating hormone) controls thyroid function. Thyroid conditions are underdiagnosed in men and can cause symptoms resembling testosterone deficiency: fatigue, weight gain, concentration problems, depressed mood.

Reference range: 0.4–4.0 mU/L.

When to act: Elevated TSH (above 4.0 mU/L) suggests hypothyroidism. Hyperthyroidism (TSH below 0.4 mU/L) is also relevant as it increases SHBG levels and can thereby lower free testosterone. Thyroid dysfunction should always be investigated before or alongside a TRT diagnosis.

10. Vitamin D

What it measures: The serum level of 25-hydroxyvitamin D — a hormone (not just a vitamin) relevant for bone health, immune function, and testosterone production. In Switzerland, vitamin D deficiency is extremely common due to geographical location — especially during winter months.

Reference range: 75–150 nmol/L (30–60 ng/mL).

When to act: Values below 50 nmol/L (20 ng/mL) are considered deficient and should be supplemented. Several studies show a positive correlation between vitamin D levels and testosterone. Correcting a vitamin D deficiency alone can moderately improve testosterone levels — particularly in men with confirmed deficiency.

The Optimal Blood Panel

For a complete assessment of hormonal and metabolic health, we recommend an extended panel that goes beyond the standard GP blood draw:

At Swiss TRT, this extended panel is routinely ordered as part of the initial diagnostic workup — for a thorough and comprehensive assessment of your health status.

FAQ

How often should I have a blood test?

For men over 30 without known pre-existing conditions, we recommend a comprehensive blood panel at least once per year. With existing TRT, checks are conducted after 6 weeks, then every 3–6 months. If you have specific risk factors (overweight, family history, chronic stress), biannual screening may be advisable. Our online self-test helps assess whether a timely blood test is recommended.

Do I need to fast for the blood draw?

For testosterone testing: yes, ideally fasting and in the morning between 7:00 and 10:00. Testosterone follows a circadian rhythm with a morning peak. HbA1c and lipid profiles are also determined fasting. A fasting period of 8–12 hours before the blood draw is optimal. Drinking water is allowed and even recommended — it facilitates blood collection.

Does health insurance cover the cost of an extended blood panel?

In Switzerland, diagnostic blood tests are covered by mandatory health insurance when a medical indication exists — meaning when a physician orders the test based on symptoms or risk factors. A "wish blood panel" without medical indication is not reimbursed. During a consultation via Swiss TRT, your physician orders the medically indicated parameters, which are then regularly billed through insurance.

What should I do if individual values are abnormal?

Individual abnormal values should always be interpreted in context — not in isolation. A slightly elevated PSA can be caused by exercise, sexual activity, or a minor prostate inflammation. A slightly low testosterone on a single day may reflect stress, sleep deprivation, or a cold. This is why at least two morning measurements are always performed when testosterone deficiency is suspected. For abnormal findings, your physician discusses the results and recommends next steps.

Further Reading

• Free vs. Total Testosterone: Which Value Counts?
• Testosterone After 30: When Levels Drop
• Telemedicine for TRT: How It Works