Fingerstick blood assay maps real-world NAD disparity across gender and age.

Nicotinamide adenine dinucleotide (NAD ) level has been associated with various age-related diseases and its pharmacological modulation emerges as a potential approach for aging intervention. But human NAD landscape exhibits large heterogeneity. The lack of rapid, low-cost assays limits the establishment of whole-blood NAD baseline and the development of personalized therapies, especially for those with poor responses towards conventional NAD supplementations. Here, we developed an automated NAD analyzer for the rapid measurement of NAD with 5 μL of capillary blood using recombinant bioluminescent sensor protein and automated optical reader. The minimal invasiveness of the assay allowed a frequent and decentralized mapping of real-world NAD dynamics. We showed that aerobic sport and NMN supplementation increased whole-blood NAD and that male on average has higher NAD than female before the age of 50. We further revealed the long-term stability of human NAD baseline over 100 days and identified major real-world NAD -modulating behaviors.