title: Estimating the precision of serial dilutions and colony counts: contribution of laboratory re-calibration of pipettes.
abstract: The basic (inherent) precision of serial dilutions and of colony counts made from them may be reliably estimated by reference solely to the pipette-manufacturer's specifications. Such estimates do not include external sources of variation and may be regarded as minima. The quality of estimation can be improved by using information gained by laboratory ('in-house') re-calibration of the pipettes. The degree of improvement was assessed by comparison with similar series made without re-calibration. It was found that improvement was minimal for colony counts but worthwhile for homogeneous solutions.
authors.affiliation: Department of Pathology and Microbiology, School of Medical Sciences, University of Bristol, Bristol BS8 1TD, UK. A.Hedges@bristol.ac.uk
authors.forename: A J
authors.initials: AJ
authors.lastname: Hedges
mesh_terms: D001419:Bacteria / Q000254:growth & development*; D015169:Colony Count, Microbial / Q000379:methods*; D008954:Models, Biological; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity