Herzog P, Edenharder R, Wiebels S, König U, Holtermüller K H
I. Medizinische Klinik, St.-Markus-Krankenhaus, Frankfurt a. M.
Z Gastroenterol. 1988 Feb;26(2):121-9.
Possible causes of false negative tests for occult fecal bleeding are hemoglobin concentrations too low to be detected or a bacterial degradation of fecal hemoglobin. In the present in vitro study the degradation of hemoglobin was assessed in cultures of fecal bacteria or in homogenates of human feces. At a hemoglobin concentration of 1.5 mg per gram stool a 48 h incubation caused a decrease of test positivity for hemoglobin of 88% (aerobic conditions) or 52% (anaerobic conditions). Thus, bacterial degradation is one of the causes of false negative test results when testing for occult fecal bleeding. These findings should be considered by the clinician when the efficiency of currently available occult blood tests in detecting right sided colonic lesions is to be assessed.
潜血试验假阴性的可能原因是血红蛋白浓度过低无法检测到，或者是粪便血红蛋白的细菌降解。在本体外研究中，在粪便细菌培养物或人类粪便匀浆中评估了血红蛋白的降解情况。在血红蛋白浓度为每克粪便1.5毫克时，48小时的孵育导致血红蛋白检测阳性率在需氧条件下降低88%，在厌氧条件下降低52%。因此，细菌降解是潜血试验检测结果假阴性的原因之一。当评估目前可用的潜血试验检测右侧结肠病变的效率时，临床医生应考虑这些发现。
