The purpose of the pivotal study is to collect blood specimens and clinical data from patients suspected of having Heart Failure (HF), which will be tested at a future date on Natriuretic Peptide assay(s) to validate diagnostic cutoffs and assess HF severity.

A prospective clinical sample collection and future natriuretic peptide testing will be conducted in an emergency department only population. Patients presenting to the Emergency Department (ED) with signs and symptoms of acute heart failure will be approached for enrollment.

Clinical and laboratory data will be collected to establish product performance and clinical concordance to adjudicated clinical diagnosis. Approximately 1800 evaluable subjects at geographically dispersed sites in the US will be enrolled in the study.

Sample collection and testing of clinical samples with the Access Natriuretic Peptide assay will be performed under two separate protocols

Inclusion Criteria:

• Signed and dated informed consent obtained
• Adult aged 21 years or older
• Presenting with a clinical suspicion of acute HF
• Subject clinical history available for review by Sponsor or delegates and FDA or other regulatory agencies

Exclusion Criteria:

• Dyspnea clearly not secondary to HF (e.g. primary lung disease or chest trauma)
• Stage 4 or 5 Chronic Kidney Disease (CKD)
• Chronic dialysis
• Participation in a clinical study that may interfere with participation in this study
• Anything that would place the individual at increased risk or preclude the individual's full compliance with or completion of the study.

The population will be representative of an acute heart failure population enrolled at Emergency Departments. Patients presenting with a suspicion of acute heart failure will be approached for enrollment.