Diagnostics - Laboratory studies

• All patients: Establish the diagnosis with routine laboratory studies, cardiac biomarkers, ECG, chest x-ray, and echocardiogram.

• If CHF is confirmed, investigate for:

  • Underlying causes (consider coronary angiogram, chest imaging, and advanced cardiac imaging)

  • Modifiable risk factors (e.g., hypertension, coronary artery disease)

• CBC: Screen for anemia and infection.

• BMP

  • Creatinine: normal or ↑

  • Na: normal or ↓ (hyponatremia can indicate a poor prognosis) [12]

  • Glucose or HbA1c: may be elevated in diabetes [13]

• Liver chemistries: Elevations, particularly of the cholestatic enzymes, can indicate hepatic venous congestion. [14][15]

• Inflammatory markers: ↑ CRP can indicate acute infection or inflammation

• Fasting lipid studies: Elevated cholesterol is a common finding.

• TSH: possibly lowered as a sign of hyperthyroidism

1. Natriuretic peptides

2. Cardiac troponin T or I

BNP or NT-proBNP (NT-proBNP is a precursor of BNP; either can be used, as long as the correct values are used for interpretation)

• To establish the diagnosis of CHF (alongside echocardiography)

• Evaluation of prognosis and disease severity (e.g., level at admission and predischarge)

• High levels in patients with classic symptoms of CHF confirm the diagnosis (high predictive index).

• High levels at discharge and no decrease during hospitalizations may signal worse outcomes.

• Raised NPs are seen in a multitude of conditions (e.g., renal impairment, ACS, effects of pharmacotherapy).

• Obesity and flash pulmonary edema can lead to normal or decreased NP levels.

• Elevated levels can suggest ischemia but troponins can be elevated in CHF without acute myocardial ischemia.

• Potentially helpful for risk stratification