What labs should be ordered for a full cardiac panel for referral to cardiology?

Recommended Laboratory Tests for a Cardiac Panel for Cardiology Referral

A comprehensive cardiac panel for referral to cardiology should include lipid profile, complete blood count, renal function tests, glucose metabolism assessment, thyroid function, and cardiac biomarkers. 1

Core Laboratory Tests

Basic Biochemistry (Essential)

• Lipid Profile

  • Total cholesterol
  • LDL cholesterol
  • HDL cholesterol
  • Triglycerides
  • Non-HDL cholesterol (calculated)
  • Consider ApoB and Lp(a) for expanded assessment 2

• Complete Blood Count

  • Hemoglobin
  • White blood cell count
  • Platelet count

• Renal Function

  • Creatinine with estimated glomerular filtration rate (eGFR)
  • Blood urea nitrogen (BUN)
  • Electrolytes (sodium, potassium, chloride, bicarbonate)

• Glucose Metabolism

  • Fasting plasma glucose
  • HbA1c
  • Consider oral glucose tolerance test if HbA1c and fasting glucose are inconclusive 1

• Thyroid Function

  • Thyroid stimulating hormone (TSH) 1

Cardiac Biomarkers

• Natriuretic Peptides

  • BNP or NT-proBNP (especially for suspected heart failure) 1

• Cardiac Troponins

  • High-sensitivity troponin T or I (if acute coronary syndrome is suspected) 1

• Inflammatory Markers

  • High-sensitivity C-reactive protein (hs-CRP) 2

Additional Tests Based on Clinical Context

For Suspected Heart Failure

• Liver function tests 1
• Iron studies (serum ferritin) if anemia is present 1

For Suspected Coronary Artery Disease with Risk Factors

• Lipoprotein-associated phospholipase A2 (Lp-PLA2) 2
• Uric acid 1

For Patients on Statin Therapy

• Liver function tests 1
• Creatine kinase (if muscle symptoms are present) 1

Interpretation and Risk Assessment

The results from these tests should be integrated with clinical findings to:

• Calculate 10-year ASCVD risk using Pooled Cohort Equations 2
• Identify modifiable risk factors
• Guide medication decisions
• Establish baseline values before initiating therapy

Important Considerations

• Fasting samples are preferred for accurate triglyceride assessment 2
• Serial monitoring of cardiac biomarkers may provide prognostic information 1
• If clinical or ECG assessment suggests acute coronary syndrome rather than chronic coronary syndrome, immediate referral to emergency department and/or repeated measurement of troponin is recommended 1
• Biomarker elevation, particularly troponin and NT-proBNP, significantly increases cardiovascular risk even in patients with otherwise low-risk profiles 1

Common Pitfalls to Avoid

1. Incomplete testing: Missing key components like renal function or thyroid function can lead to inappropriate treatment decisions
2. Over-reliance on single markers: Cardiac risk assessment requires integration of multiple biomarkers with clinical findings
3. Failure to repeat abnormal results: Confirm unexpected abnormal values before making treatment decisions
4. Not considering pre-analytical factors: Time of day, fasting status, and recent exercise can affect certain biomarker levels
5. Ignoring age and sex-specific reference ranges: Particularly important for cardiac biomarkers like troponin and NT-proBNP

This comprehensive cardiac panel provides the essential information needed for appropriate cardiology referral and subsequent management decisions, focusing on markers that impact morbidity, mortality, and quality of life outcomes.