Blood tests
Blood tests can be useful in screening patients for evidence of heart failure and to look for possible causes, triggers or complications of heart failure.
Natriuretic peptide (BNP, NT-proBNP):
The heart releases hormones, so-called natriuretic peptides, when the heart muscle is stretched due to pressure or fluid. These hormones have a mild diuretic and salt losing effect which is favourable for patients with heart failure. Two types of natriuretic peptides, BNP or NT-proBNP, can be measured routinely from a simple blood test taken by your primary physician or cardiologist. An elevated level of a natriuretic peptide is seen in patients with heart failure, and the levels will rise if the patient’s heart failure changes. Therefore, the measurement of BNP in patients with heart failure is useful in both diagnosis and management decisions. BNP and NT-proBNP can be raised in other conditions like kidney disease and reduced in people who are obese. Importantly, a normal BNP value in a person not being treated for heart failure indicates that the symptoms are most likely due to other causes, i.e. heart failure is very unlikely. This makes the test also very useful in screening for heart failure.
Other blood tests:
If heart failure is suspected, a number of blood tests may be done. There is no set list of blood tests that should be done in all patients with heart failure. The number of laboratory tests required depends on factors like age, severity of symptoms, and known comorbidities such as diabetes, anaemia or reduced kidney function. Once heart failure has been diagnosed, blood tests can help to check if any other organs may be affected. These blood tests will detect any electrolyte imbalance, diabetes, problems with your liver or kidneys, thyroid function, anaemia, iron deficiency, and elevated levels of natriuretic peptides. Some of these blood tests may need to be taken regularly to monitor the patient’s progress over time.
