not thoroughly mixing blood, inaqequate mixing of diluted specimen, failure to discard first few drops, counting cells inaccurately, not loading chamber properly, calculation error, clerical error
What errors are inherent in hemacytometry?
"field errors", statistical error
How does a field error occur?
relates to the random distribution of cells on the counting chamber
How does a statistical error occur?
when total number of cells is too low to give statistical confidence in result (reduced when large number of cells are counted)