To validate the NTproBNP2 Test Kit by using the test results of the predicate device as a reference. It will be demonstrated that the investigational product (NTproBNP2 Test Kit) and the predicate are equivalent. Subsequently, it will be demonstrated that the investigational product can be used in clinical testing.

Inclusion Criteria:

Samples that meet all the following criteria will be eligible for enrollment:

1. Samples from subjects with current or previous signs and/or symptoms of heart failure, or diagnosed heart failure.
2. Sample-related information is available, including a unique and traceable number, sample type, age, gender, date of sample collection, and clinical diagnosis, etc..
3. The sample volume is adequate, no less than 2 mL of whole blood.
4. The sample collection shall meet the informed consent waiver requirements of the ethics committee.

Exclusion Criteria:

Samples that meet any of the following criteria will be excluded:

1. Duplicate collection of samples from the same subject.
2. Samples that do not meet the collection, handling, and storage requirements outlined in the product's instructions for use.
3. Samples that are suspected of being poor quality, i.e. samples suspected of containing clots, visible hemolysis or lipids, or samples suspected of being contaminated with possible interfering substances.

The study should select subjects that cover the intended population, considering differences in disease, age, and gender. It should not focus on a specific age group to ensure population representativeness. The samples (from the subject) contain interference also need to be involved.