Traditional analysis of FST between samples is complicated by recent admixture.
The quantitative detection of cytokines from tissue samples is complicated by the low expression rates and the short half-lives of the cytokine proteins.
Since targets in EBC are very dilute, contamination from oral or GI tract has to be monitored; three, detection of bacterial metabolites in human samples is complicated by substantial overlap between bacterial and host metabolites.
For example, the study of clinical samples is complicated by cellular, genetic, environmental and treatment heterogeneities.
Quantification of miRNA expression in tissue samples is complicated by the fact that one has no obvious direct means to identify appropriate endogenous controls that may be used to normalize expression data and correct for differences in the amount of RNA analyzed or the efficiency of miRNA extraction or cDNA conversion in samples from different tissues.
The analysis of trace levels of PFOS, PFOA, and PFOSA in biologic samples is complicated by contamination, particularly by leaching from Teflon plastic.
Moreover, although M. catarrhalis is focused on by clinicians, the isolation of M. catarrhalis from clinical samples is complicated by the presence of Neisseria strains because these organisms share morphological similarities [ 49].
Unfortunately, the detection of c-Met phosphorylation in human formalin-fixed, paraffin-embedded samples is complicated by the poor stability of phospho-epitopes in general [ 39, 40] and by the limited sensitivity and specificity of phospho-specific antibodies [ 41, 42].
Estimates based on these samples generally produce results that are qualitatively similar to those for adult samples; however, interpretation of whole-population samples is complicated because they can be strongly affected by assumptions about juvenile survival rates, which are poorly known for many species.
