NPPB and heart failure: If we test the sensitivity and specificity of elevated NT-proBNP levels (including heart failure and pulmonary causes) with the rapid kit, we can get a value of 96% and 56%, respectively, with an accuracy of 59.2% (Tables 4, 5). Hence, we can observe an increased specificity if considering only the elevated NT-proBNP levels as the primary endpoint of the rapid kit.