Bernhard E, Nitschke Y, Khursigara G, et al. - There was no significant difference between the results and the reported standard range of plasma inorganic pyrophosphate (PPi) in adults (2-5 µM). The described adenosine triphosphate (ATP) sulfurylase method is proposed as a diagnostic tool for measuring PPi levels in plasma as a biomarker in the pediatric population.

• Plasma samples were obtained from 200 children aged 1 day to 18 years who had blood tests for medical conditions that did not affect plasma PPi levels.

• The ATP sulfurylase assay had an analytical sensitivity range of 0.15 to 10 µM PPi.

• On identical samples, the inter- and intra-assay coefficients of variability were less than 10%.

• The standard range of PPi in the blood plasma of children and adolescents aged 0 to 18 years was calculated to be 2.36 to 4.44 µM, with a median of 3.17 µM, and no difference between male and female probands.

• PPi plasma levels did not vary significantly across pediatric age groups.