How to Read Your Bloodwork Report: A Men's Guide to What the Numbers Mean

Reference ranges on lab reports are statistical, not clinical targets. A range of 8–30 nmol/L for testosterone, for example, means a reading of 9 nmol/L is 'within range' — but a 35-year-old man at 9 nmol/L is almost certainly symptomatic (low energy, poor recovery, reduced libido). The lab won't flag it. Your GP may not flag it. You need to know what to look for.

A useful mental model: reference range = 'not immediately dangerous'. Optimal = 'where you function best and minimise long-term disease risk'. These are different thresholds for almost every marker on your panel. The sections below give both.

Pattern recognition matters as much as individual values. A testosterone of 15 nmol/L looks fine in isolation. Pair it with SHBG of 65 nmol/L (meaning very little is bioavailable), elevated LH, and low-normal free testosterone, and the picture shifts significantly.

Total testosterone (TT): Lab reference typically 8–30 nmol/L (AU/NZ/UK) or 270–1070 ng/dL (US). Optimal for a man under 50: 18–25 nmol/L (520–720 ng/dL). Below 12 nmol/L warrants investigation regardless of age. Above 30 nmol/L without exogenous testosterone warrants investigation for rarer causes.

Free testosterone (fT): The biologically active fraction. Reference varies by lab method. Optimal: >0.30 nmol/L (direct) or >2.5% of TT. Low fT with normal TT often means elevated SHBG — your body is making adequate testosterone but most of it is bound and unavailable.

SHBG (Sex Hormone Binding Globulin): Reference 10–57 nmol/L. Optimal for men who want good free testosterone availability: 20–40 nmol/L. Chronically elevated SHBG (>55) blunts free testosterone even when TT looks normal. Causes: excess thyroid hormone, liver issues, low insulin, ageing. LH and FSH sit above this axis — elevated LH with low TT means primary hypogonadism (testis issue); low LH with low TT means secondary (pituitary/hypothalamus issue). This distinction matters for treatment.

Fasting glucose: Reference 3.9–6.0 mmol/L. Optimal: 4.0–5.2 mmol/L. Anything above 5.5 mmol/L fasting in a non-diabetic man is worth watching — it's the early warning zone where diet and training changes are highly effective.

HbA1c: Reference < 5.7% (< 39 mmol/mol). Optimal: 4.6–5.3% (27–35 mmol/mol). HbA1c reflects average glucose over 90 days. A value of 5.6% is 'normal' but the research on cardiovascular risk suggests optimal sits below 5.4%. This is the marker that catches the slow metabolic drift most men don't feel until year 3–5.

Fasting insulin: Often not included in standard panels — request it specifically. Reference varies wildly by lab (some use <25 mIU/L). Optimal: <8 mIU/L fasting. Elevated fasting insulin in the presence of normal glucose is early insulin resistance — the most actionable finding in metabolic health because it precedes HbA1c elevation by years.

Total cholesterol: Reference <5.5 mmol/L (AU). Context matters — a total cholesterol of 4.0 mmol/L driven by very low HDL is worse than 5.5 mmol/L with high HDL and low triglycerides. Total cholesterol alone is a weak predictor of cardiovascular risk.

LDL-C: Reference <3.0 mmol/L (primary prevention). Optimal for men with zero other risk factors: <2.5 mmol/L. The form of LDL matters too — ask for ApoB or LDL particle number if available. Small, dense LDL particles are more atherogenic than large, fluffy ones at the same LDL-C value.

HDL-C: Reference >1.0 mmol/L (men). Optimal: >1.4 mmol/L. HDL is the most trainable lipid fraction — aerobic exercise raises it more reliably than anything else. Triglycerides: Reference <2.0 mmol/L. Optimal: <1.0 mmol/L. Triglycerides above 1.5 mmol/L almost always indicate excess refined carbohydrate, alcohol, or both. The triglyceride-to-HDL ratio (TG/HDL) is one of the strongest simple predictors of insulin resistance — optimal is <1.0 (SI units).

ALT (Alanine aminotransferase): Reference <45 U/L (men). Optimal: <25 U/L. ALT is the most liver-specific marker. Chronically elevated ALT in a man with moderate alcohol intake and visceral fat is the canary in the coalmine for fatty liver. The good news: ALT responds rapidly to dietary change — a 30-day alcohol break plus caloric restriction often drops it 40–60%.

GGT (Gamma-glutamyl transferase): Reference <65 U/L (men). Optimal: <25 U/L. GGT is exquisitely sensitive to alcohol — it often rises before ALT. If GGT is elevated and ALT is normal, chronic moderate drinking is the most common cause. GGT is also independently associated with cardiovascular risk above 30 U/L in epidemiological data.

AST/ALT ratio: When AST > ALT (ratio > 2), consider alcoholic liver disease or non-liver causes (muscle breakdown, cardiac). When ALT > AST, non-alcoholic fatty liver disease (NAFLD) is more typical.

TSH (Thyroid Stimulating Hormone): Reference 0.5–4.5 mIU/L. Optimal: 1.0–2.5 mIU/L. TSH above 3.0 mIU/L in a symptomatic man (fatigue, weight gain, cold intolerance, low libido) warrants a full thyroid panel: free T3, free T4, and anti-TPO antibodies. Sub-clinical hypothyroidism (TSH 3–4.5, normal T4) is undertreated and often missed.

Vitamin D (25-OH): Reference 50–250 nmol/L (AU). Optimal: 100–150 nmol/L. The reference range lower limit (50 nmol/L) is set for bone health minimum — optimal immune, testosterone, and mood function appears to require higher levels. Bali expats often assume they're sufficient due to sun exposure; indoor workers routinely test deficient.

Ferritin: Reference 30–300 µg/L (men). Optimal: 100–200 µg/L. Ferritin doubles as an iron store and an acute-phase inflammatory marker. Very high ferritin (>300) warrants investigation for haemochromatosis, metabolic syndrome, or alcohol. Low ferritin (<50) — even in men — causes fatigue and poor recovery.