Men's Health Blood Tests Guide

Key blood tests for men's health

PSA screening: what men need to know

PSA (prostate-specific antigen) is a protein produced by prostate cells. Elevated PSA can indicate: prostate cancer (the 2nd most common cancer in men), benign prostatic hyperplasia (BPH, non-cancerous enlargement), prostatitis (infection or inflammation). PSA is not a perfect test. It can be elevated without cancer and normal with cancer. Current guidelines vary: the American Cancer Society recommends discussing PSA screening with men from age 50 (45 if high risk, Black men or family history; 40 if very high risk). A rising PSA over time (PSA velocity) is more informative than a single value.

Testosterone deficiency (Low T): recognition and testing

Low testosterone (hypogonadism) is significantly underdiagnosed. It affects approximately 2–6% of men aged 40–79. Symptoms, fatigue, reduced libido, erectile dysfunction, low mood, muscle loss, belly fat gain, are non-specific and often attributed to ageing or stress. Always test morning testosterone (7–10am) as levels are 30–40% higher in the morning. If low, confirm with a repeat test and add LH/FSH to determine whether the problem is the testes (primary) or pituitary (secondary).

Recommended blood test schedule for men

Lifestyle factors that most impact men's blood results

• Visceral (belly) fat: raises triglycerides, lowers HDL, raises fasting glucose and insulin resistance, and suppresses testosterone
• Alcohol: raises GGT, triglycerides and uric acid; damages liver
• Smoking: accelerates atherosclerosis; doubles heart attack risk
• Sleep apnoea (affects 40% of obese men): lowers testosterone, raises blood pressure and blood sugar
• Physical inactivity: major driver of metabolic syndrome, insulin resistance and low testosterone

Questions to ask your doctor

• Is my testosterone level low?
• Should I have a PSA test?
• What is my cardiovascular risk score?
• Is my GGT elevated due to alcohol or fatty liver?
• Should I have a colonoscopy?

References

Sources cited on this page. PubMed links open the original abstract.

1. Siegel RL, Miller KD, Fuchs HE, Jemal A. Cancer statistics, 2022. CA Cancer J Clin. 2022;72(1):7–33. PMID 35020204 · doi:10.3322/caac.21708

Prostate health – PSA testing and what it means

Prostate-specific antigen (PSA) is a protein produced by the prostate gland that leaks into the bloodstream in greater quantities when the prostate is enlarged, inflamed, or cancerous. PSA testing is the most commonly used prostate cancer screening tool, but its interpretation is nuanced:

PSA is age-dependent: a PSA of 2 ng/mL in a 50-year-old man is more concerning than the same value in a 70-year-old. Age-specific thresholds used in practice: under 50: above 2.5 ng/mL warrants urological referral; 50–69: above 3.0 ng/mL; 70+: above 4.0 ng/mL. However, PSA is not prostate-cancer-specific – it rises with benign prostatic hyperplasia (BPH), prostatitis, UTI, urinary catheterisation, ejaculation (PSA transiently rises by 0.5 ng/mL for 48 hours), vigorous exercise, and cystoscopy. PSA should not be measured after any of these activities.

PSA velocity (rate of rise) and PSA density (PSA divided by prostate volume on ultrasound) improve its predictive value. A PSA rising by more than 0.75 ng/mL per year is a stronger cancer signal than a single elevated result. The NHS currently runs an "Informed Choice" programme offering PSA testing on request to men over 50 who are counselled about its benefits and limitations – unlike structured screening, there is no national PSA screening programme in England.

Testosterone – the male hormonal screen

Testosterone deficiency (male hypogonadism) causes fatigue, low libido, erectile dysfunction, depression, reduced muscle mass, increased body fat, and osteoporosis. It is significantly under-diagnosed. Key blood tests:

• Total testosterone: Should be measured between 7 and 11 am (levels peak in the early morning). A fasting sample is preferred. Below 8–12 nmol/L (laboratory-dependent) is hypogonadal; borderline values (8–15 nmol/L) require repeat measurement with SHBG for free testosterone calculation.
• SHBG (sex hormone binding globulin): Binds testosterone – only "free" testosterone is biologically active. High SHBG (common in older men, liver disease, hyperthyroidism) can give a normal total testosterone with a low free testosterone (symptomatic hypogonadism). Low SHBG (obesity, hypothyroidism, metabolic syndrome) can give low total testosterone but normal free testosterone.
• LH and FSH: Distinguish primary hypogonadism (testes failing – LH/FSH raised as pituitary tries to compensate) from secondary hypogonadism (pituitary/hypothalamus failing – LH/FSH inappropriately low). Secondary hypogonadism warrants MRI pituitary to exclude prolactinoma or other pituitary tumour.
• Prolactin: Hyperprolactinaemia suppresses GnRH, causing secondary hypogonadism. A prolactinoma (pituitary tumour) causes LH/FSH and testosterone suppression, often with galactorrhoea – treated with dopamine agonists (cabergoline), not testosterone replacement.