NPPB and heart failure: Simple, rapid, and sensitive assays are always needed in clinical settings.[17] To show the applicability of LFSMiA for clinical use, it was evaluated for NT‐proBNP detection, a key clinical biomarker of heart failure.[18] As NT‐proBNP naturally presents in human blood circulation, we first measured the baseline level of NT‐proBNP in the pooled human plasma, which was determined to be 8.23 pg mL−1.