Disclosed is a portable non-destructive testing (NDT) instrument system that transmits spectrum data measured from a test material sample to a remotely located computer for computation of the sample's atomic element composition. The atomic element composition is subsequently transmitted back to the portable instrument for display to the operator in real time. The precision and accuracy of the compositional computation is improved by the greater processing power of the high performance remote computer. The operator of the NDT instrument may choose to use the remote computer to perform part or all of the compositional computation.