Cardiac Blood Tests for Suspected or Known Cardiovascular Disease
All patients with suspected or known cardiovascular disease require a core panel of blood tests including lipid profile with LDL-C, full blood count with hemoglobin, creatinine with estimated renal function, and glycemic assessment with HbA1c and fasting glucose. 1
Essential Initial Blood Tests
Mandatory Core Panel (Class I Recommendations)
Lipid profile including LDL-C: Required for risk stratification and to guide statin therapy targeting LDL-C <55 mg/dL (<1.4 mmol/L) in established coronary disease 1
Full blood count: Hemoglobin and white cell count provide prognostic information and identify anemia as a potential cause or aggravating factor of cardiac symptoms 1
Creatinine with estimated renal function: Essential before initiating renin-angiotensin-aldosterone blockade and for risk stratification, as renal dysfunction negatively impacts prognosis 1
Glycemic status assessment: HbA1c and fasting plasma glucose are required in all patients; add oral glucose tolerance test if these are inconclusive, given the strong association between diabetes and adverse cardiovascular outcomes 1
Thyroid Function Testing
Assess thyroid function at least once in patients with suspected chronic coronary syndromes, as thyroid disorders can precipitate or worsen cardiac ischemia 1
Measure TSH and free T4 when clinical suspicion exists for thyroid disorders, particularly in patients with new-onset hypothyroidism and established coronary disease, as hypothyroidism is arrhythmogenic and requires prompt treatment 1, 2
Cardiac-Specific Biomarkers
Troponin Testing
High-sensitivity or ultrasensitive troponin assays are the preferred cardiac biomarkers and are mandatory when acute coronary syndrome is suspected. 1
Immediate troponin measurement is required if clinical or ECG assessment suggests acute coronary syndrome rather than chronic coronary syndrome 1
Repeat troponin at 6-12 hours after symptom onset if initial troponin is negative in patients presenting within 6 hours of symptoms 1
Do not routinely measure troponin in stable outpatients with chronic coronary disease, as very low levels detected by high-sensitivity assays lack sufficient independent prognostic value to justify systematic measurement 1
Measure troponin in all hospitalized patients with symptomatic stable coronary disease to identify potential instability 1
Natriuretic Peptides (BNP/NT-proBNP)
Consider BNP or NT-proBNP measurement (Class IIa recommendation) in patients with suspected heart failure to help exclude cardiac disease if normal, or identify those requiring detailed cardiac assessment if markedly elevated 1
Normal natriuretic peptide levels make significant cardiac disease unlikely (negative predictive value for heart failure) 3, 4
BNP cutoff of approximately 31-67 pg/mL may enhance sensitivity for detecting coronary disease when combined with other non-invasive tests, though specificity decreases 5, 6
Monitoring Tests for Statin Therapy
Liver function tests are required early after beginning statin therapy 1
Creatine kinase measurement is required in patients taking statins who develop symptoms suggestive of myopathy 1
Annual Reassessment in Established Disease
Annual monitoring of lipids, glucose metabolism, and creatinine is required in all patients with known stable coronary artery disease. 1
Key Clinical Pitfalls
Avoid using hs-CRP routinely: Despite associations with increased event risk, multiple reporting and publication biases make its independent prognostic value too uncertain for routine measurement 1
Do not use multimarker panels indiscriminately: While adding CK-MB or myoglobin to troponin may improve sensitivity for acute myocardial infarction, this comes at the cost of decreased specificity 1, 5
Do not rely on troponin point-of-care testing alone in the prehospital setting as a primary diagnostic test 1
Recognize that BNP increases sensitivity but decreases specificity: The tradeoff makes BNP unsuitable for routine use in all chest pain patients, though it may be valuable in selected cohorts 5