Above all mostly cardiologists know about this test. That is not surprising as until recently the fact that the heart also produces hormones when under stress has been unknown as well. These hormones lower the burden by helping to eliminate water from the circulation.
This test measures a molecule with the complicated name NT-proBNP (which is a longer protein fragment of the pro-brain-natriuretic peptide with one nitrogen atom at its one end) and therefore it is called proBNP. Very little amount of blood is needed to make the sure statement whether specifically the left heart ventricle - which is doing most of the pumping - is overloaded.
If the test result is below 125 pg/ml then the reason for the main symptom dyspnoea is not caused by the heart but most likely by the lung. A specific search should be started then. The test values are higher in women comparing to men and increase also with increasing age. A value of 200 pg/ml found in a 75-year old lady may be therefore regarded as quite normal.
At emergency admission to the hospital with dyspnoea and possibly further signs of heart failure only a value of above 1000 pg/ml shows clearly a failing heart which should be then treated immediately.
This test may be used additionally for risk prognosis for the future. The higher the vales the more likely this person will develop circulatory problems, mainly such as myocardial infarction, repeated hospitalisations, stroke or even premature death.
People with known risk factors such as diabetes or hypertension show often also increased NT-proBNP values.
The good news is that in simple cases and especially at the start of developing a heart failure you can do a lot by exercising. Exercise showed to improve the values also in the quite sick people. To loose weight in case of obesity and a healthy living style help as well. In people who have to be treated for heart failure this test can be used to control and to adjust the treatment.
In some countries there is good reimbursement so you can get the test without a problem (e.g. USA). In other countries it may be necessary to pay cash yourself and it may be quite expensive (approx. 22 Euro in Germany).
It would be very helpful if most of the general practitioners knew about this test, especially since there is a simple device to deliver the result in 15 minutes. This device is similar to the diabetics glucose self control devices just a bit bigger. Consequently, it can do also other important tests such as troponin T which is crucial when there is a suspicion of acute myocardial infarction.