因為蘿卜裏麵有種酶，有肯能導致便潛血假陽性。

The basis of the guaiac test is that the pseudoperoxidase of hemoglobin oxidizes guaiac to form a blue-colored quinone compound, after the addition of a hydrogen peroxide developer. The likelihood of a positive guaiac test is related to the amount of blood present in the stool. Normally, about 0.5 to 1.5 mL of blood is lost daily into the GI tract. The FOBT test requires approximately 2 mL/day of blood to be positive; to be consistently positive requires more. Several factors have an impact on FOBT performance characteristics. Bleeding from proximal gastrointestinal lesions, including the right colon, may allow for degradation of the heme, which will then not catalyze the guaiac reaction. The myoglobin or hemoglobin in red meat can give a false-positive reaction, although ingesting 8 oz of cooked red meat daily has only a 5% probability of giving a positive test result. Peroxidase-rich raw vegetables and fruits (turnips, parsnips, horseradish, artichokes, mushrooms, radishes, broccoli, cauliflower, beets, apples, oranges, bananas, melons, grapes, pears, plums, cantaloupe) may give a false-positive result if fecal specimens are tested immediately after collection. However, plant peroxidases are unstable with time; therefore, if a specimen is developed several days after collection, the likelihood of a false-positive test result because of plant peroxidases is reduced.

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• 謝謝！ -dudaan- ♂ (0 bytes) () 04/15/2013 postreply 10:51:50