Sample bias can occur in multiple stages of histological analysis:
Sample Collection: If the tissue sample is not representative of the entire organ or condition, it may lead to incorrect conclusions. For example, selecting a non-cancerous region of a tumor can result in a false-negative diagnosis. Fixation: Improper fixation can lead to uneven preservation of tissues, causing certain structures to be overrepresented or underrepresented. Sectioning: The technique used to cut tissue samples can introduce bias. For instance, cutting sections that are too thick or too thin can either obscure details or make them too prominent. Staining: Variability in staining procedures can result in differential staining of tissue components, skewing the observed results. Microscopy: The choice of magnification and the field of view can also introduce bias. Focusing on areas that appear more interesting or pathological can lead to an overestimation of certain conditions.
