Cardiomegaly laboratory findings

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor in Chief: Cafer Zorkun, M.D., Ph.D. [2]

Laboratory tests that should be obtained when a person is suspected or known to have cardiomegaly are: a complete blood count, thyroid stimulating hormone levels, and a blood urea nitrogen. These are common, high yield tests. Other tests can be ordered based on suspicions as to the underlying cause of the cardiomegaly, obtained through patient history and physical examination.

Based upon the history and physical, a standard evaluation might include:

Common high yield tests:

• Complete blood count (CBC): to rule out anemia.
• Thyroid stimulating hormone (TSH)
• Blood urea nitrogen (BUN) / creatinine)

Less frequent low yield tests:

• Erythrocyte sedimentation rate (ESR): to evaluate autoimmune causes.
• Calcium: to rule out hypocalcemia.
• Magnesium: to rule out hypomagnesemia.
• Rheumatoid factor
• Antinuclear antibody (ANA)
• Glucose
• Pheochromocytoma screening.
• Phosphorus: to rule out hypophosphatemia.
• Blood culture

• Electrolytes should be periodically checked in the patient treated with a diuretic to avoid hypokalemia.
• Brain Natriuretic Peptide (BNP) levels may provide insight into the ongoing magnitude of LV dysfunction.

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