Effect of vitamin C on the three test methods of fecal occult blood test

Abstract

[Objective]To investigate the effect of different contents of vitamin C on the three test [Methods]of fecal occult blood test(FOBT).[Methods]On the contrast of distilled water,Benzidine,Pyramidon,Colloidal gold were used to test samples with positive and negative result of FOBT with different contents of vitamin C.[Results]In vitro tests,there was no pseudo-positive result in negative samplesof FOBT with 5,75,100,125,250 mg/ml of vitamin C by the three different test [Methods]; however,when using positive samples of FOBT,pseudo-negative results were found by the [Methods]of Benzidine and Pyramidon when the contents of vitamin C were 5,125,250 mg/ml and the contents of hemoglobinwere 0.2-10,50-75,125 mg/ml.What's more,it was not so easy for the vitamin C to influence the positive sample when the hemoglobin becomes more and more,there was no effect on the method of colloidal gold.[Conclusions]In vitro tests,for the [Methods]of Benzidine and Pyramidon,it has no influence on negative samples of FOBT and it can result in pseudo-negative result when using positive samples of FOBT when the content of vitamin C is smaller than or equal to 250 mg/ml; For the method of Colloidal gold,it has no influence on negative and positive samples of FOBT with different density of vitamin C. Key words: Vitamin C ; Benzidine ; Pyramidon ; Colloidal gold ; Fecal occult blood test ;