Heart Failure Biomarkers and Their Normal Ranges

Heart failure is a complex condition that requires accurate diagnosis and ongoing monitoring. Several key indicators are commonly used in clinical practice to assess heart function and determine the severity of heart failure. Understanding these markers and their normal ranges is essential for both patients and healthcare providers.

Ejection Fraction (EF)

One of the most commonly referenced metrics in heart failure diagnosis is the ejection fraction, often abbreviated as EF. This measurement is derived from an echocardiogram and reflects the percentage of blood pumped out of the heart's left ventricle with each beat. A normal EF typically falls within the range of 50% to 70%. However, it's important to note that some patients may experience heart failure even with a normal EF, a condition often referred to as heart failure with preserved ejection fraction (HFpEF).

Conversely, when the EF drops below 40%, it indicates a reduced ejection fraction, which is associated with more severe heart dysfunction. In some cases, EF may fall below 35%, which is considered significantly impaired and may warrant more aggressive treatment strategies. Values between 40% and 50% are generally classified as borderline or mildly reduced EF, suggesting early or mild heart failure.

B-type Natriuretic Peptide (BNP) and NT-proBNP

Another crucial biomarker in heart failure evaluation is B-type natriuretic peptide (BNP) or its precursor fragment, NT-proBNP. These peptides are released into the bloodstream when the heart is under stress, making them valuable indicators of cardiac strain. Elevated levels of BNP or NT-proBNP are strongly correlated with the presence and severity of heart failure.

Age-Specific Normal Ranges for NT-proBNP

For individuals under 50 years of age: The normal level of NT-proBNP should generally be below 450 pg/mL.

For adults between 50 and 75 years old: A normal NT-proBNP level typically falls within the range of 450 to 900 pg/mL.

For those aged 75 years and older: The normal upper limit is generally considered to be 1800 pg/mL. It's important to interpret these values in the context of other clinical findings, as age-related changes can influence biomarker levels.

In summary, while ejection fraction and natriuretic peptide levels are vital tools in diagnosing and managing heart failure, they should be interpreted alongside other clinical assessments and patient-specific factors. Regular monitoring of these indicators can help guide treatment decisions and improve patient outcomes.