Used as an indicator (red at pH 6.8, yellow at 8.0), as a vital dye to stain granules and vacuoles in living cells, in testing the secretion of acid by the stomach (given with a test meal), and in general histologic staining. SYN: toluylene red.
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neutral red n a basic phenazine dye used chiefly as a biological stain and acid-base indicator
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a basic red fluorochrome dye used as a pH indicator with a range of 6.8 (red) to 8 (yellow) and as a stain, particularly for supravital staining of granules and vacuoles.Medical dictionary. 2011.