In individuals who had been infected with M. tuberculosis in the past, the number of circulating effector cells could be low, causing negative results in a short-incubation assay but positive responses after a prolonged incubation, as reported by our studies and by others [ 11, 28].
Glucose-6-phosphate dehydrogenase (G6PD) deficiency and antibody-mediated hemolysis were excluded as causes (negative result for Coombs test).
Some of these inconsistencies can be explained by false positives and off-target effects, but some RNAi reagents are weak or ineffective and cause false negative results.
Steroid treatment significantly reduces F-FDG uptake in the tumor and can cause false negative results of F-FDG PET in the diagnosis of PCNSL.
All of our DNA samples contained amplifiable DNA at amounts that correlated with Pico-green assays when tested by Alu-element Yd6; therefore, PCR inhibitors do not cause our negative results from the Guthrie cards.
Therefore, we think that i.p. administration may generally lead to overestimation of luciferase activity of IP tumours relative to extraabdominal tumours rather than causing "false" negative results in intraperitoneal lesions.
Indeed, normalization of homocysteine levels through vitamin administration is rarely achieved in this population, and this fact could explain, among other causes, the negative results of intervention trials designed to lower cardiovascular risk.
The results show that: (i) measures of community phylogenetic diversity and dispersion are generally more sensitive to loss of resolution basally in the phylogeny and less sensitive to loss of resolution terminally; and (ii) the loss of phylogenetic resolution generally causes false negative results rather than false positives.
Moreover, the presence of an adjacent modification might prevent binding of an antibody to the target modification, causing false negative results.
When there is only a single dsRNA targeting the gene that did not result in the predicted screen signature, it is not possible to distinguish among potential causes of negative results.
