Methods

In a recently published paper, a standardised model for NT-proBNP was developed in cooperation between the Department of CongenitalCongenital. Heart Defects and Paediatric Cardiology (Director Prof. Ewert) and the Institute of Laboratory Medicine (Director Prof. Holdenrieder) (Palm et al. Continuous, complete and comparable NT-proBNP reference ranges in healthy children. Clin Chem Lab Med. 2020; 58: 1509-1516).

This sets the absolute NT-proBNP concentration in relation to reference values determined to the day, analogous to a Z-value: this so-called zlog value of NT-proBNP (abbreviated zlog-proBNP) indicates the number of standard deviations by which the measured NT-proBNP concentration is above or below the age-dependent mean value. Zlog values between -1.96 and +1.96 are in the reference range (central 95% of healthy person values), lower or higher values are outside the reference range. Due to the underlying dynamics of the mathematical model, the calculation of zlog-proBNP is valid for children between 1 day and 18 years (regardless of gender).

Results

Due to the standardisation carried out, the reference interval of zlog-proBNP is independent of age. This not only enables the assessment of progression values and facilitates the recognition and assessment of pathological values, but for the first time also creates the basis for a practical use of this promising biomarker in everyday paediatric cardiology.