title: Making standards for quantitative real-time pneumococcal PCR.
abstract: QuantitativelytAPCR is often performed using in-house standards. We hypothesised equivalence when measuring a standard suspension ofStreptococcus pneumoniaeby colony-forming-units (CFU) or genome-copies. Median (IQR) ratio of CFU/genome-copies was 0.19 (0.1-1.2). Genome-copies were less variable than CFU, but the discrepancy between the methods highlights challenges with absolute quantification.
authors.affiliation: KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya; Nuffield Department of Clinical Medicine, University of Oxford, Oxford, United Kingdom.
authors.forename: Susan C
authors.initials: SC
authors.lastname: Morpeth
authors.affiliation: Molecular & Cell Biology, LGC, London, United Kingdom.
authors.forename: Jim F
authors.initials: JF
authors.lastname: Huggett
authors.affiliation: Department of Pathology, University of Otago, Christchurch, New Zealand; Microbiology Unit, Canterbury Health Laboratories, Christchurch, New Zealand.
authors.forename: David R
authors.initials: DR
authors.lastname: Murdoch
authors.affiliation: KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya; Nuffield Department of Clinical Medicine, University of Oxford, Oxford, United Kingdom; Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, United Kingdom.
authors.forename: J Anthony G
authors.initials: JA
authors.lastname: Scott
keywords: Quantitative; Real-time PCR; Standards; Streptococcus pneumoniae