Sample Types: serum. Range: 0- 640 pmol/L. Sensitivity: 3 pmol/L. Time: 3.5 hours ? The Eagle Biosciences NT-proBNP ELISA Assay Kit (enzyme-linked immunoassay kit) is intended for the quantitative determination of human Nt-proBNP in serum. The NT-proBNP ELISA Assay Kit is manufactured by Biomedica. The NT-proBNP ELISA Assay Kit is for research use only and not to be used in diagnostic procedures.