The Meixner test has been advocated as clinically useful in determining the presence of amanitin toxin in a mushroom sample, but the detection limit has not been established. It is unknown whether illness can occur with an amanitin-containing mushroom that yields a negative Meixner test result. The detection limit may not be low enough to identify the presence of a toxic amount of amatoxin. Another potential problem with the Meixner test is the possibility that cross-reacting substances (in-doles) present in nonhepatotoxic mushroom species will confuse interpretation of the Meixner test.