FAQ - Actim Fecal Blood
Q: Why does the dipstick container need to be brought to room temperature before opening?
A:To ensure proper function of the dipsticks they need to be kept dry during storage. For this purpose, desiccant is added to each aluminum container. However, if the container is opened when it is still cold, it may absorb humidity from the atmosphere, which may damage the remaining dipsticks in the container.
Q: How long can the sample be stored before analyzing?
A: Hemoglobin in a non-treated fecal sample is rapidly degraded. However, the buffer in the Sample Dilution Buffer tube is designed to protect the fecal hemoglobin from degradation and a diluted sample can be stored for days.
Q: What should be done if no control line appears?
A: The control line confirms correct performance of the test. If the control line does not appear, the test result is invalid and should be repeated with another dipstick. However, occasionally, a small air bubble may form at the lower end of the perforating device. If it is visible, and no liquid flow has been observed in the test, the inverting of the tube may be repeated a second time with the same dipstick.
Q: Why is there no need for diet restrictions before the sample is taken?
A: The guaiac tests are based on the peroxidase reaction of hemoglobin, and interference of the reaction may occur from food substances containing hemoglobin or other peroxidase activities. These include all meats and certain plants that need to be omitted from the diet for three days prior to sampling. The monoclonal antibodies in the Actim Fecal Blood test recognize human hemoglobin only and have not shown cross-reactivity to hemoglobin from other species. Therefore the test result is not affected by the patient’s diet, and the sample can be taken without preliminary preparations.
Q: Why does the tube need to be inverted slowly?
A: The test is performed by slowly inverting the tube for approximately 2 seconds and is then placed on the table to develop. The movement of inverting must be tranquil, and care must be taken not to use too harsh movements. If the test tube is turned too vigorously, there is a possibility, that the liquid enters also the sides of the dipstick, causing a similar effect as dipping above the dip area. This may lead to immobilization or inappropriate aggregation of the latex particles and may end up in giving an invalid result.
Q: At 10 minutes, only the control line appeared, but some weak lines appeared later on. How should the result be interpreted?
A: A positive result can be interpreted as soon as two blue lines become visible in the result window, however a negative test must be confirmed at 10 minutes. As the immunochromatography reaction continues to develop over time, the lines may become stronger or even new lines may appear in the result area. These lines must not be interpreted as positive as they indicate analyte levels below the cut-off value of the test.