Medical Staff Pulse Newsletter

Cora Labs to Use New Assay Starting March 24

The Core Laboratories within the Department of Pathology and Laboratory Medicine will be going live with an N-terminal pro B-type natriuretic peptide (NT-proBNP) assay (Roche Diagnostics) beginning Tuesday, March 24.

We are adding this offering for heart failure, as we have already been running an intact BNP assay (Abbott Laboratories) for years. While NT-proBNP is derived from BNP, the concentrations in vivo do not correlate 1:1, hence different reference intervals are used for both.

The addition of NT-proBNP is relevant now as use of Entresto for heart failure becomes more common. Entresto (Sacubatril/Valsartan) inhibitis neprilysin, which initially shifts the BNP concentration to the right (e.g., increases BNP concentration), as the intact form is preserved for longer.

At first it was thought that this increase in BNP values for patients taking Entresto would obfuscate accurate interpretation and follow-up of patients. However, BNP remains a clinically valid biomarker with independent prognostic value similar with that of NT-proBNP, according to results of the PARADIGM-HF trial released in March 2019, as the concentration over time will ultimately be what matters (J Am Coll Cardiol2019 Mar, 73 (11) 1264-1272). That said, use of NT-proBNP, which shows an initial decrease with use of Entresto, may be preferred to avoid initial clinical confusion. Ultimately, both markers can be used post 8-10 weeks for accurate prognosis.

Reference ranges for flagging of results in CS-Link™ are shown below. However, additional interpretive comments that further stratify results by age will be posted with results.

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If you have questions, contact Kimia Sobhani at kimiasobhani@cshs.org, or Anders Berg, PhD, at anders.berg@cshs.org.