Brain natriuretic peptide (BNP) is an acknowledged marker of heart failure (HF) that is widely used in clinical practice for HF diagnosis and patient management.
BNP is known as an unstable molecule (1, 2). Several recent studies have revealed that BNP is presented by multiple forms in HF patients’ plasma, truncated from both N- and C-termini and only a small portion of BNP circulates as a full-size BNP32 molecule (3). The majority of commercially available BNP assays are designed as sandwich-type immunoassays utilizing two MAbs specific to distantly located epitopes. At least one of these two antibodies is specific to the ring structure, while the other one is usually specific to the C terminus of the BNP molecule. Recent data regarding BNP instability in circulation suggests that immunoassays utilizing at least one MAb specific to the terminal epitope could underestimate the real BNP content in the blood sample.
HyTest specialists have recently developed antibodies for a brand new type of BNP immunoassay - the “Single Epitope Sandwich” immunoassay (SES assay) - which differs from all commercially available “conventional”- type sandwich BNP assays (4).
In the SES assay the capture antibody (MAb 24C5, epitope 11-17) which is specific to the relatively stable ring part of BNP molecule recognises antigen. The detection antibody is specific only to the complex of the capture antibody with the BNP (or proBNP) and does not recognize these two molecules (capture antibody and BNP) separately. Therefore only a single epitope of BNP molecule is needed for this novel type of sandwich BNP immunoassay. This feature provides additional advantages to the SES assay over conventional BNP assays in terms of a higher apparent stability of BNP antigen in the sample or bloodstream.
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