The DFA transaminase test provides rapid categorical measurement of ALT in a whole blood specimen taken via finger-stick. The test is based on the platform technology of "paper microfluidics" (also known as "patterned paper"), in which hydrophobic barriers are patterned into a sheet of paper in order to create microfluidic, hydrophilic paths within the paper, through which flow can be directed towards specific detection zones. The test is designed for visual color-coded readout in three ALT ranges ("bins") that correspond to the ranges of AST and ALT (<3x the upper limit of normal (ULN), 3-5x ULN, and >5x ULN) currently used for clinical management decisions per US TB and HIV treatment guidelines. The bin cutoffs are common to treatment guidelines used around the globe, including those used by the Vietnam Ministry of Health.