Initial Laboratory Workup for Patients
For patients presenting with suspected heart failure, the initial laboratory evaluation should include: complete blood count, urinalysis, serum electrolytes (including calcium and magnesium), blood urea nitrogen, serum creatinine, fasting blood glucose (glycohemoglobin), lipid profile, liver function tests, and thyroid-stimulating hormone. 1
Core Laboratory Panel
The following tests constitute the essential initial workup for patients with suspected cardiac disease:
Hematologic and Metabolic Assessment
- Complete blood count (CBC) to evaluate for anemia, infection, or hematologic abnormalities that may contribute to or complicate heart failure 1
- Serum electrolytes including sodium, potassium, calcium, and magnesium to assess for imbalances that affect cardiac function and guide diuretic therapy 1
- Blood urea nitrogen (BUN) and serum creatinine to evaluate renal function, which is critical for prognosis and medication dosing 1
Metabolic and Endocrine Screening
- Fasting blood glucose and glycohemoglobin (HbA1c) to screen for diabetes mellitus, a major risk factor for cardiovascular disease 1
- Lipid profile to assess cardiovascular risk and guide statin therapy 1
- Thyroid-stimulating hormone (TSH) because thyroid dysfunction can precipitate or exacerbate heart failure 1
Hepatic Function
- Liver function tests including AST, ALT, alkaline phosphatase, total bilirubin, and albumin to detect hepatic congestion from heart failure or identify alternative diagnoses 1
- These tests help distinguish between hepatocellular injury (elevated transaminases) and cholestatic patterns (elevated alkaline phosphatase) 2, 3
Urinalysis
- Urinalysis to screen for proteinuria, hematuria, or signs of renal disease that may contribute to volume overload 1
- Dipstick analysis should be followed by microscopic examination when abnormalities are detected 4
Context-Specific Considerations
For Oncology Patients
When evaluating patients with suspected malignancy, additional baseline tests are required:
- For renal masses: CBC, comprehensive metabolic panel (including calcium, LDH), coagulation profile, and urinalysis 1
- For hepatobiliary cancers: Hepatitis panel (HBsAg, HBcAb, HCV antibodies), AFP, complete blood count, and assessment of hepatic functional reserve using Child-Pugh scoring 1
- For pediatric leukemia: Tumor lysis syndrome panel (LDH, uric acid, potassium, phosphate, calcium), disseminated intravascular coagulation panel (D-dimer, fibrinogen, PT, PTT), and pregnancy testing for patients of childbearing potential 1
Important Caveats
Avoid screening asymptomatic populations with comprehensive liver panels, as this is not cost-effective and may lead to unnecessary workups 5. However, targeted screening is appropriate for high-risk groups (e.g., patients over 60, diabetics, pregnant women for bacteriuria) 4.
Interpret transaminase elevations carefully, as levels are affected by body mass index and sex, and defining "normal" can be challenging 3. Mild chronic elevations warrant evaluation for viral hepatitis, alcohol use, fatty liver disease, and medication toxicity 2.
Do not rely on single tests when evaluating liver disease—a panel approach (AST, alkaline phosphatase, bilirubin, albumin) provides superior sensitivity and specificity 5, 6.