Measurement of acylcarnitine substrate to product ratios specific to biotin-dependent carboxylases offers a combination of indicators of biotin status in humans.
Bogusiewicz A, Horvath TD, Stratton SL, Mock DM, Boysen G. Measurement of acylcarnitine substrate to product ratios specific to biotin-dependent carboxylases offers a combination of indicators of biotin status in humans. J Nutr. 2012 Sep; 142(9):1621-5.