Coronary artery disease (CAD) is one of the leading causes of cardiovascular morbidity and mortality. Atherosclerosis often develops silently for years before presenting with angina, myocardial infarction or other cardiovascular events. Therefore, preventive health assessment should not begin only when symptoms appear. Laboratory investigations can help identify several important and potentially modifiable cardiovascular risk factors at an earlier stage. However, no single blood test can diagnose or exclude CAD in an asymptomatic individual. The value lies in interpreting a group of laboratory parameters together with age, blood pressure, family history, smoking, obesity, diabetes and other clinical factors.
Lipid Profile: The Foundation of Cardiovascular Risk Assessment
A lipid profile remains one of the most important laboratory investigations for cardiovascular risk assessment. It generally includes total cholesterol, LDL cholesterol (LDL-C), HDL cholesterol (HDL-C) and triglycerides, from which non-HDL cholesterol can also be calculated. Among these, LDL-C is a major modifiable contributor to atherosclerosis. Persistently elevated concentrations of atherogenic lipoproteins are associated with progressive plaque formation in the arterial wall. However, cardiovascular risk should not be judged by LDL-C alone. Triglycerides, non-HDL cholesterol and the overall clinical risk profile can provide additional information.
Lipoprotein(a): The Often-Missed Risk Factor
Lipoprotein(a), or Lp(a), is an important additional laboratory marker because its concentration is predominantly genetically determined. An elevated Lp(a) is associated with increased lifetime risk of atherosclerotic cardiovascular disease and aortic valve disease. Since Lp(a) is relatively stable throughout life, measurement at least once in adulthood can identify an inherited cardiovascular risk that may not be apparent from a routine lipid profile. It can be particularly informative in individuals with a family history of premature cardiovascular disease or cardiovascular disease that appears disproportionate to conventional risk factors.
Apolipoprotein B: Counting the Atherogenic Particles
Apolipoprotein B (ApoB) provides a different perspective from LDL-C. LDL-C measures the amount of cholesterol contained within LDL particles, whereas ApoB reflects the number of circulating atherogenic particles, including LDL and other ApoB-containing lipoproteins. This distinction can become particularly useful in people with elevated triglycerides, diabetes, metabolic syndrome or discordance between LDL-C and the overall cardiovascular risk profile. Thus, ApoB may help identify residual atherogenic risk that is not fully captured by LDL-C alone.
Glucose and HbA1c: Detecting Diabetes-Related Cardiovascular Risk
Diabetes and prediabetes are major risk factors for cardiovascular disease. Fasting plasma glucose and HbA1c are therefore important components of preventive health screening. HbA1c provides an estimate of average blood glucose exposure over the preceding approximately 2–3 months, while fasting glucose provides a current measurement under standardised fasting conditions. Identifying prediabetes or diabetes provides an opportunity for early intervention because prolonged hyperglycemia contributes to endothelial dysfunction, inflammation and accelerated atherosclerosis.
High-sensitivity C-reactive protein: An Additional Marker of Cardiovascular Risk
High-sensitivity C-reactive protein (hs-CRP) is a marker of low-grade systemic inflammation. Chronic inflammation plays an important role in atherosclerosis, and elevated hs-CRP may identify additional cardiovascular risk in selected individuals. However, hs-CRP is not a specific test for CAD. Infection, inflammatory disorders, obesity and other conditions can increase the value. Therefore, it should be interpreted in the appropriate clinical context rather than used as an isolated “heart disease test.”
Kidney Function Test: An Important Cardiovascular Connection
Assessment of serum creatinine and estimated glomerular filtration rate (eGFR) can also contribute to cardiovascular risk assessment. Chronic kidney disease is associated with substantially increased cardiovascular risk. Where clinically appropriate, urine albumin-to-creatinine ratio (ACR) provides additional information about renal and vascular risk. Thus, kidney-related laboratory parameters are relevant even when the primary objective of the health check-up is cardiovascular prevention.
Thyroid Function Test: A Useful Metabolic Assessment
TSH, with free T4 when indicated, may be useful when there are clinical features or risk factors suggesting thyroid dysfunction. Both overt hypothyroidism and hyperthyroidism can influence cardiovascular health, including lipid metabolism and cardiac rhythm. Thyroid testing is therefore better considered as a selective component of cardiovascular risk evaluation, rather than a universal CAD-specific test.
Complete Blood Count: A Supportive, Not CAD-Specific Test
A CBC is not a test for coronary artery disease, but it may provide useful supporting information. Significant anemia can increase cardiac workload and may contribute to symptoms such as fatigue, breathlessness or reduced exercise tolerance. Conversely, abnormal hemoglobin or hematocrit values may require further evaluation. CBC should therefore be interpreted as part of the overall health assessment rather than as a direct marker of coronary plaque.
Cardiac Troponin: Important, But Not a Routine Screening Test
High-sensitivity cardiac troponin (hs-cTnI or hs-cTnT) is one of the most important biomarkers in the diagnosis and risk assessment of suspected acute myocardial injury. However, it should not be considered a routine preventive screening test for CAD in healthy asymptomatic individuals. Its greatest clinical value comes when interpreted in the appropriate clinical setting, particularly in patients with symptoms suggestive of acute coronary syndrome.
Key message: “A heart check-up is not just about cholesterol.” Cardiovascular risk is influenced by atherogenic lipoproteins, diabetes, blood pressure, kidney function, inflammation, genetics and lifestyle-related factors. Laboratory testing can help identify several of these risks before a cardiovascular event occurs.
At the same time, no blood test alone can rule out coronary artery disease. The greatest value comes from combining laboratory findings with the patient's clinical history and overall cardiovascular risk assessment.
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