Blood Tests for Heart Health
Cardiovascular disease is Australia's leading killer. The right blood tests can reveal your risk years before symptoms appear — when prevention is still possible.
Why Blood Tests Matter for Heart Health
Cardiovascular disease (CVD) kills more Australians than any other disease — approximately 42,000 deaths per year, or one Australian every 12 minutes. Yet the majority of heart attacks and strokes are preventable. The challenge is that atherosclerosis (the gradual build-up of plaque in arteries) develops silently over decades, and the first symptom is often a catastrophic event.
Blood tests are the foundation of cardiovascular risk assessment because they measure the biological processes driving plaque formation: cholesterol deposition, inflammation, blood sugar damage, and organ stress. When combined with blood pressure, family history, and lifestyle factors, these markers allow your GP to calculate your 5-year absolute cardiovascular risk using the Australian Cardiovascular Risk Calculator.
The Heart Foundation recommends that all Australians aged 45+ (or 30+ for Aboriginal and Torres Strait Islander peoples) have a heart health check with their GP. Most of the blood tests below are bulk billed under Medicare as part of this check.
8 Blood Tests That Reveal Your Heart Risk
Lipid Panel (Cholesterol, LDL, HDL, Triglycerides)
Why this matters for your heart: The lipid panel is the cornerstone of cardiovascular risk assessment. LDL cholesterol (the "bad" cholesterol) is the primary driver of atherosclerosis — it infiltrates arterial walls, triggering inflammation and plaque formation that narrows blood vessels over decades. HDL cholesterol (the "good" cholesterol) removes LDL from arterial walls and transports it back to the liver for disposal. Triglycerides are the third piece of the puzzle — elevated levels are independently associated with heart disease, particularly in combination with low HDL. The ratio of total cholesterol to HDL is one of the strongest predictors of cardiovascular events, more reliable than any single number alone.
Optimal range: Total cholesterol below 5.5 mmol/L. LDL below 2.0 mmol/L (high risk) or below 3.4 mmol/L (low risk). HDL above 1.0 mmol/L (men) or above 1.2 mmol/L (women). Triglycerides below 1.7 mmol/L. Non-HDL cholesterol (total minus HDL) below 2.5 mmol/L (high risk) — this is increasingly considered more accurate than LDL alone because it captures all atherogenic particles.
Watch out: A "normal" total cholesterol does not mean your heart risk is low. You can have normal total cholesterol but dangerously high LDL and low HDL. Always look at the full panel, not just the total number. Also: triglycerides must be fasted (12 hours) for accurate results, but LDL/HDL can be measured non-fasting. Some labs now offer non-fasting lipid panels — check with your GP.
HbA1c (Diabetes and Heart Risk)
Why this matters for your heart: Diabetes doubles your risk of heart disease and stroke — it is considered a "cardiovascular risk equivalent," meaning a diabetic with no history of heart disease has the same risk as a non-diabetic who has already had a heart attack. Chronically elevated blood sugar damages the endothelium (inner lining of blood vessels), accelerates atherosclerosis, promotes clot formation, and impairs the ability of damaged vessels to repair themselves. HbA1c measures your average blood sugar over 3 months and is the most reliable single marker for both diabetes diagnosis and cardiovascular risk stratification. Pre-diabetes (HbA1c 42-47 mmol/mol) also significantly elevates cardiovascular risk.
Optimal range: HbA1c below 42 mmol/mol (6.0%) for non-diabetics. Fasting glucose 4.0-5.4 mmol/L. For diabetics, the target HbA1c depends on individual circumstances but is generally below 53 mmol/mol (7.0%). Every 1% reduction in HbA1c reduces cardiovascular events by approximately 14% and heart attack risk by 16%.
Watch out: HbA1c is included in the Australian Absolute Cardiovascular Risk Calculator along with cholesterol, blood pressure, smoking status, age, and sex. Your GP can calculate your 5-year absolute risk using these factors — this is far more useful than any single number in isolation. Ask for this calculation at your next heart health check.
CRP and hs-CRP (Vascular Inflammation)
Why this matters for your heart: Atherosclerosis is fundamentally an inflammatory disease, not just a plumbing problem. High-sensitivity CRP (hs-CRP) measures low-grade chronic inflammation in blood vessel walls — the type that drives plaque formation and, critically, plaque rupture (which is what actually causes heart attacks). The JUPITER trial demonstrated that people with elevated hs-CRP but normal cholesterol still had a 44% reduction in heart events when treated with statins, proving that inflammation is an independent cardiovascular risk factor. Standard CRP measures acute inflammation (infection, injury), while hs-CRP is sensitive enough to detect the subtle chronic inflammation of vascular disease.
Optimal range: hs-CRP below 1.0 mg/L is low cardiovascular risk. 1.0-3.0 mg/L is moderate risk. Above 3.0 mg/L is high risk — but this must be interpreted in the absence of acute illness (a cold or infection will temporarily spike CRP above 10 mg/L and invalidate the cardiovascular interpretation). Two readings 2 weeks apart are recommended for reliable risk stratification.
Watch out: Standard CRP and hs-CRP are DIFFERENT tests using different assays. Standard CRP measures down to about 5 mg/L, while hs-CRP measures down to 0.1 mg/L. For cardiovascular risk assessment, you specifically need hs-CRP. Ensure your GP requests "high-sensitivity CRP" on the pathology form. Also: obesity, smoking, gum disease, and sleep apnoea all elevate hs-CRP — treating these modifiable factors can lower your hs-CRP and your cardiovascular risk.
Homocysteine
Why this matters for your heart: Homocysteine is an amino acid produced during the metabolism of methionine (from dietary protein). At elevated levels, it directly damages the endothelium (inner lining of arteries), promotes blood clot formation, accelerates LDL oxidation, and impairs the production of nitric oxide (which keeps blood vessels flexible). Each 5 umol/L increase in homocysteine raises cardiovascular risk by approximately 20%. Elevated homocysteine is strongly linked to B12 deficiency, folate deficiency, and certain genetic variants (MTHFR mutations, present in 10-15% of the population). It is particularly useful for assessing cardiovascular risk in younger adults who may have normal cholesterol but elevated homocysteine.
Optimal range: Homocysteine should be below 15 umol/L. Optimal is below 10 umol/L. Above 15 umol/L is considered hyperhomocysteinaemia and warrants investigation of B12, folate, and kidney function. Above 30 umol/L is moderate elevation; above 100 umol/L is severe and suggests a genetic disorder (homocystinuria).
Watch out: Homocysteine is not part of a standard cardiovascular risk panel — your GP must specifically request it. Medicare will bulk bill homocysteine when there is a clinical indication (cardiovascular risk assessment, family history of early heart disease, or suspected B12/folate deficiency). The sample must be processed quickly (within 30 minutes) or placed on ice, as homocysteine leaks from red blood cells over time, giving falsely high results.
BNP and NT-proBNP (Heart Failure Markers)
Why this matters for your heart: B-type natriuretic peptide (BNP) and its precursor NT-proBNP are released by the heart muscle when it is stretched or under pressure — essentially, they are your heart's distress signal. These markers are the gold standard blood test for diagnosing and monitoring heart failure. They are also elevated in conditions that strain the heart: pulmonary hypertension, pulmonary embolism, severe valve disease, and cardiac amyloidosis. In general practice, BNP/NT-proBNP is particularly valuable for distinguishing cardiac from non-cardiac causes of breathlessness — a normal level essentially rules out heart failure as the cause of your symptoms.
Optimal range: BNP below 100 pg/mL or NT-proBNP below 300 pg/mL makes heart failure very unlikely. NT-proBNP above 125 pg/mL (under 75 years) or above 450 pg/mL (over 75 years) warrants further investigation with echocardiography. Higher levels correlate with more severe heart failure and worse prognosis.
Watch out: BNP/NT-proBNP are NOT routine screening tests — they are ordered when heart failure is suspected (breathlessness, ankle swelling, fatigue with exertion). Obesity paradoxically LOWERS BNP levels (fat tissue clears BNP), so obese patients can have heart failure with "normal" BNP. Kidney disease raises NT-proBNP because it is cleared by the kidneys. Age and sex also affect levels — interpretation requires clinical context.
Kidney Function (eGFR, Creatinine)
Why this matters for your heart: Your kidneys and heart are intimately connected — the "cardiorenal axis." Chronic kidney disease (CKD) is an independent cardiovascular risk factor, as powerful as diabetes. Even mild kidney impairment (eGFR 45-60) doubles cardiovascular risk compared to normal kidney function. The kidneys regulate blood pressure through the renin-angiotensin system, manage fluid balance (which directly affects cardiac workload), and clear waste products that damage blood vessels when they accumulate. Creatinine and eGFR are also essential before starting medications like ACE inhibitors, ARBs, or SGLT2 inhibitors — all commonly used in cardiovascular disease management. Potassium must be monitored because both high and low potassium can trigger fatal cardiac arrhythmias.
Optimal range: eGFR above 90 mL/min/1.73m2 is normal. 60-89 is mildly decreased (common in older adults, may be normal). Below 60 is CKD stage 3 and significantly increases cardiovascular risk. Creatinine: 60-110 umol/L (men), 45-90 umol/L (women). Potassium: 3.5-5.0 mmol/L (outside this range, cardiac rhythm is at risk).
Watch out: eGFR is an estimate based on creatinine, age, and sex — it can be inaccurate in very muscular people (falsely low eGFR due to high creatinine from muscle mass) and in people with very low muscle mass (falsely high eGFR). If kidney function is borderline, a cystatin C-based eGFR provides a more accurate estimate. Always check urine albumin/creatinine ratio (ACR) alongside eGFR — albuminuria is an early marker of kidney AND cardiovascular damage.
Liver Function Tests
Why this matters for your heart: The liver is central to cardiovascular health because it manufactures cholesterol, produces clotting factors, processes medications (including statins), and clears inflammatory markers. Non-alcoholic fatty liver disease (NAFLD) — now the most common liver condition in Australia, affecting 25-30% of adults — is strongly associated with cardiovascular disease. Elevated GGT is independently associated with cardiovascular mortality, even at levels within the "normal" range. ALT and AST elevations may indicate NAFLD, alcohol-related liver damage, or medication toxicity (important for statin monitoring). Albumin is a marker of liver synthetic function and overall nutritional status — low albumin predicts poor cardiovascular outcomes.
Optimal range: ALT below 40 U/L (ideally below 25 U/L for optimal metabolic health). GGT below 50 U/L (men) or below 30 U/L (women). AST below 40 U/L. Albumin 35-50 g/L. GGT above 30 U/L in women or above 50 U/L in men, even if technically "normal," is associated with increased cardiovascular risk and metabolic syndrome.
Watch out: Statins (the most commonly prescribed cardiovascular medication) can elevate ALT. Your GP should check liver function before starting a statin and again at 3 months. Mild elevations (up to 3x normal) are acceptable and do not require stopping the medication. However, if ALT rises above 3x normal with symptoms (nausea, fatigue, dark urine), the statin should be stopped and an alternative considered.
Full Blood Count
Why this matters for your heart: A full blood count provides several cardiovascular risk markers. Haemoglobin reveals anaemia, which forces the heart to work harder to deliver oxygen — chronic anaemia can cause or worsen heart failure. Haematocrit (the percentage of blood volume occupied by red cells) is associated with cardiovascular events when elevated — thick blood increases clot risk and blood pressure. Platelets that are too high promote clotting (thrombosis risk), while platelets that are too low increase bleeding risk (important for patients on anticoagulants). The white blood cell count, particularly the neutrophil-to-lymphocyte ratio (NLR), is emerging as a powerful predictor of cardiovascular events — an elevated NLR indicates chronic inflammation driving atherosclerosis.
Optimal range: Haemoglobin: 130-170 g/L (men), 120-150 g/L (women). Haematocrit: 0.40-0.54 (men), 0.36-0.47 (women). Platelets: 150-400 x10^9/L. WBC: 4.0-11.0 x10^9/L. The neutrophil-to-lymphocyte ratio (NLR) below 3.0 is associated with lower cardiovascular risk; above 3.0 suggests chronic inflammation.
Watch out: Polycythaemia (high haemoglobin/haematocrit) is a cardiovascular risk factor that is sometimes overlooked. Haematocrit above 0.48 in women or above 0.52 in men significantly increases stroke and heart attack risk through blood viscosity. Chronic conditions like sleep apnoea and smoking cause secondary polycythaemia. If your haematocrit is consistently elevated, mention it to your GP.
Heart Risk Assessment: What Your Numbers Mean
This table shows how individual blood markers contribute to cardiovascular risk. Remember that absolute risk (calculated from all factors combined) is more meaningful than any single number.
| Marker | Low Risk | Moderate Risk | High Risk |
|---|---|---|---|
| Total Cholesterol | Below 5.0 mmol/L | 5.0-6.5 mmol/L | Above 6.5 mmol/L |
| LDL Cholesterol | Below 2.0 mmol/L | 2.0-3.4 mmol/L | Above 3.4 mmol/L |
| HDL Cholesterol | Above 1.5 mmol/L | 1.0-1.5 mmol/L | Below 1.0 mmol/L |
| Triglycerides | Below 1.0 mmol/L | 1.0-1.7 mmol/L | Above 1.7 mmol/L |
| hs-CRP | Below 1.0 mg/L | 1.0-3.0 mg/L | Above 3.0 mg/L |
| HbA1c | Below 39 mmol/mol | 39-47 mmol/mol | Above 48 mmol/mol |
| Homocysteine | Below 10 umol/L | 10-15 umol/L | Above 15 umol/L |
| eGFR | Above 90 mL/min | 60-89 mL/min | Below 60 mL/min |
| Fasting Glucose | Below 5.0 mmol/L | 5.0-6.0 mmol/L | Above 6.1 mmol/L |
What to Ask Your Doctor
Ready-to-use script for your GP appointment:
“I would like a comprehensive cardiovascular risk assessment. I am [age] and have [risk factors: family history, smoking, diabetes, high blood pressure, overweight]. Could we check my lipid panel, HbA1c, kidney function, and hs-CRP? I would also like you to calculate my absolute cardiovascular risk score.”
Lipid Panel (fasted — Total cholesterol, LDL, HDL, Triglycerides)
HbA1c and Fasting Glucose
hs-CRP (high-sensitivity CRP)
Kidney Function (eGFR, Creatinine, Potassium)
Liver Function Tests (ALT, GGT)
Full Blood Count
Homocysteine (if family history of early CVD)
Urine Albumin/Creatinine Ratio
Warning Signs of Heart Attack and Stroke
Blood tests assess long-term risk. But if you experience any of the following symptoms, do not wait for blood test results — call 000 immediately.
The Comprehensive Heart Health Panel
This panel covers the blood markers recommended for cardiovascular risk assessment. Most are bulk billed as part of a Medicare heart health check.
| Test | What It Checks | Cost (Australia) |
|---|---|---|
| Lipid Panel (TC, LDL, HDL, TG) | Cholesterol levels and cardiovascular plaque risk | Bulk billed |
| HbA1c | 3-month blood sugar — diabetes is a major cardiac risk factor | Bulk billed |
| Fasting Glucose | Current blood sugar and pre-diabetes screening | Bulk billed |
| hs-CRP (High-Sensitivity CRP) | Vascular inflammation — independent heart risk marker | Bulk billed |
| Homocysteine | Amino acid linked to arterial damage and clotting risk | Bulk billed* |
| Kidney Function (eGFR, Creatinine) | Kidney health — closely linked to heart function | Bulk billed |
| Liver Function (ALT, GGT) | Fatty liver disease, statin monitoring | Bulk billed |
| Full Blood Count | Anaemia, haematocrit, inflammation markers | Bulk billed |
| Potassium and Electrolytes | Cardiac rhythm and muscle function | Bulk billed |
| Urine Albumin/Creatinine Ratio | Early kidney and vascular damage marker | Bulk billed |
* Homocysteine is bulk billed when ordered with a clinical indication such as family history of early cardiovascular disease, suspected B12/folate deficiency, or documented cardiovascular risk assessment. Some pathology providers may charge a small gap fee — check with your provider.
Related Reading
Check Your Heart Health Markers
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SmarterBlood provides health information and AI-powered blood test analysis. It is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your doctor or qualified health provider with any questions about cardiovascular health.