Lingual ascorbic acid test: poor correlation with blood and tissue levels of ascorbic acid in guinea pigs

The lingual ascorbic acid test, based on the reduction and decolorization of the blue dye, 2,6-dichloroindophenol sodium, was evaluated in a group of guinea pigs conditioned to have a wide range of ascorbic acid levels in the tissues. The test did not correlate well with ascorbic acid levels in either blood or tissue.