Could I get a positive test result, but not have hereditary hemochromatosis (a “false positive”)?
The transferrin saturation test can be falsely elevated if you did not fast before the test. If you were fasting, getting a false-positive result depends on the “cut-off” value used for the test. Cut-off levels range from 45% to 62%. Recommendations to make 45% the cut-off are designed to detect as many true positives as possible. If your value is higher than 45%, the possibility of hereditary hemochromatosis increases. If the cut-off were 50%, there would be fewer false positives, but testing would also miss some people with hereditary hemochromatosis. Choosing cut-off values is difficult because the percent saturation that reliably indicates hereditary hemochromatosis will vary with diet, age and gender. The ferritin test could be elevated from another illness that causes inflammation, or from some types of cancer. The false-positive rate is essentially zero for the DNA test. In other words, if the DNA test is positive, a change has been detected in your hereditary hemochromatosis ge
