Abstract
The limit of detection (LOD) is a critical performance characteristic of an assay that requires careful evaluation during method validation. However, formal calculations for the LOD do not take into account atypical data sets that are generated from real-time PCR techniques, which can be non-normally distributed, truncated, and heteroscedastic. Experimental data sets for the quantification of genetically modified (GM) material were produced using real-time PCR, in order to model the LOD. A bootstrapping computer simulation calculated the probabilities of detecting PCR positive test results from these data sets, and computer modelling defined a function from the resulting probability plots. The LOD was modelled as a function of sample replication level and cycle threshold values. The broad applicability of this bootstrapping and data modelling approach should be of general interest to laboratories conducting trace-level detection.
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References
Saunders G, Parkes H (eds) (1999) Analytical molecular biology: quality and validation. RSC, Cambridge, pp 1–72
Foy CA, Parkes HC (2001) Emerging homogeneous DNA-based technologies in the clinical laboratory. Clin Chem 47:990–1000
McNaught A, Wilkinson A (1997) Compendium of chemical terminology—IUPAC Recommendations. Blackwell, Amsterdam, ISBN 0 86542 684 8
BS ISO 11843–1 (1997) Capability of detection—Part 1: Terms and conditions
BS ISO 11843-4 (2003) Capability of detection—Part 4: Methodology for comparing the minimum detectable value with a given value
Prichard E, co-ordinating author (2001) Analytical measurement terminology. Published for LGC by the Royal Society of Chemistry, Thomas Graham House, Science Park, Cambridge, ISBN 0-85404-443-4
Draft International Harmonisation of Pharmacopoeias (1993) Text in validation of analytical procedure. Pharmeuropa 5(4):341
MU ad-hoc group; ISO/FDIS 24276 (2005) International standard, foodstuffs—methods of analysis for the detection of genetically modified organisms and derived products—general requirements and definitions
EURACHEM /CITAC Guide CG 4 Quantifying uncertainty in analytical measurement, 2nd edn
Directive 2001/18/EC, Official Journal L 106 (17/04/2001) p1–39. The European Parliament and the Council of the European Union, Brussels
European Commission Regulation (EC) No. 1830/1997 Official Journal Eur Communities L 268 (18.10.2003). The European Parliament and the Council of the European Union, Brussels
European Commission Regulation (EC) No. 1829/2003 Official Journal Eur Communities L 268/1 (18.10.2003). The European Parliament and the Council of the European Union, Brussels
Burns M, Corbisier P, Wiseman G, Valdivia H, McDonald P, Bowler P, Ohara K, Schimmel H, Charels D, Damant A, Harris N (2006) Comparison of plasmid and genomic DNA calibrants for the quantification of genetically modified ingredients. Euro Food Res Technol 224(2):249–258 doi:10.1007/s00217-006-0376-z
World Trade Organization—World Trade Report (2006) Exploring the links between subsidies, trade and the WTO
FAO report: The state of Food and Agriculture 2003–2004. Agricultural biotechnology—meeting the needs of the poor. Food and Agriculture Organization of the United Nations, Rome
Kay S, Van den Eede G (2001) The limits of GMO detection. Nat Biotechnol 19:405
Holst-Jensen A, Berdal K (2004) The modular analytical procedure and validation approach and the units of measurement for genetically modified materials in foods and feeds. J AOAC Int 87(4):927–936
Trapmann S, Catalani P, Conneely P, Corbisier P, Gancberg D, Hannes E, Le Guern L, Kramer G, Prokisch J, Robouch P, Schimmel H, Zeleny R, Pauwels J (2002) The certification of reference materials of dry-mixed soya powder with different mass fractions of Roundup ReadyTM Soya—IRMM-410S. ISBN 92-894-3725-1
Arumuganathan K, Earle E (1991) Plant Mol Biol Rep 9: 211–215
Angen Ø, Jensen J, Lavritsen D (2001) Evaluation of 5′ nuclease assay for detection of Actinobacillus pleuropneumoniae. J Clin Microbiol 39(1):260–265. doi:10.1128/JCM.39.1.260-265.2001
Yang S, Lin S, Khalil A, Gaydos C, Nuemberger E, Juan G, Hardick J, Bartlett J, Auwaerter P, Rothman R (2005) Quantitative PCR assay using sputum samples for rapid diagnosis of Pneumococcal pneumonia in adult emergency department patients. J Clin Microbiol. 43(7):3221–3226. doi:10.1128/JCM.43.7.3221-3226.2005
Backus J, Laughlin T, Wang Y, Belly R, White R, Baden J, Min CJ, Mannie A, Tafra L, Atkins D, Verbanac KM (2005) Identification and characterization of optimal gene expression markers for detection of breast cancer metastasis. J Mol Diagn 7(3):327–336
Lindecrona R, Jensen T, Andersen P, Miller K (2002) Application of a 5′ nuclease assay for detection of Lawsonia intracellularis in fecal samples from pigs. J Clin Microbiol 40:984–987
Rodriguez-Lazaro D, Hernandez M, Esteve T, Hoorfar J, Pla M (2003) A rapid and direct real time PCR-based method for identification of Salmonell app. J Microbial Methods 54(3):381–390
Foy C, Parkes H (2001) Emerging homogeneous DNA-based technologies in the clinical laboratory. Clin Chem 47:990–1000
Burns M, Nixon G, Foy C, Harris N (2005) Standardisation of data from real-time quantitative PCR methods—evaluation of outliers and comparison of calibration curves. BMC Biotechnol 5:31. doi:10.1186/1472-6750-5-31
Sharp J (2002) Development of immunomagnetic capture (IMC) based techniques for the detection of Salmonella on poultry carcasses. MSc thesis, Virginia Polytechnic Institute and State University, Blacksburg
Nielsen C, Berdal K, Holst-Jensen A (2004) Characterisation of the 5′ integration site and development of an event-specific real-time PCR assay for NK603 maize from a low starting copy number. Euro Food Res Technol 219:421–427
Berdal K, Holst-Jensen A (2001) Roundup Ready® soybean event-specific real-time quantitative PCR assay and estimation of the practical detection and quantification limits in GMO analyses. Euro Food Res Technol 213:432–438
Rønning S, Vaïtilingom M, Berdal K, Holst-Jensen A (2003) Event specific real-time quantitative PCR for genetically modified Bt11 maize (Zea mays). Euro Food Res Technol 216:347–354
Hübner P, Waiblinger H-U, Pietsch K, Brodmann P (2001) Validation of PCR methods for quantitation of genetically modified plants in food. J AOAC Int 84:1855–1864
Holst-Jensen A, Rønning S, Løvseth A, Bredal K (2003) PCR technology for screening and quantification of genetically modified organisms (GMOs). Anal Bioanal Chem 375:985–993
Ibrahim M, Kulesh D, Saleh S, Damon I, Esposito J, Schmaljohn A, Jahrling P (2003) Real-time PCR assay to detect Smallpox virus. J Clin Microbiol 41:3835–3839
Kulesh D, Baker R, Loevless B, Norwood D, Zwiers S, Mucker E, Hartmann C, Herrera R, Miller D, Christensen D, Wasieloski L, Huggins J, Jahrling P (2004) Smallpox and pan-Orthopox virus detection by real-time 3′-minor groove binder TaqMan assays on the Roche LightCycler and the Cepheid Smart Cycler Platforms. J Clin Microbiol 42(2):601–609
Zimmermann B, El-Sheikhah A, Nicolaides K, Holzgreve W, Hahn Sinuhe (2005) Optimized real-time quantitative PCR measurement of male fetal DNA in maternal plasma. Clin Chem 51:1598–1604
Ellison S, English C, Burns M, Keer J (2006) Routes to improving the reliability of low level DNA analysis using real-time PCR. BMC Biotechnol 6:33. doi:10.1186/1472-6750-6-33
Schiavo S, Yang W, Chin N, Kruill I (2005) Comparison of fluorometric detection methods for quantitative polymerase chain reaction (PCR). J Immunoassay Immunochem 26(1):1–12
Schwarz G, Baulmer S, Block A, Felsenstein F, Wenzel G (2004) Determination of detection and quantification limits for SNP allele frequency estimation in DNA pools using real time PCR. Nucleic Acids Res 32(3). doi:10.1093/nar/gnh020
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The work presented here was part of the “Government Chemist 2005–2008 Programme” and was funded by the Department of Trade and Industry, UK.
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Burns, M., Valdivia, H. Modelling the limit of detection in real-time quantitative PCR. Eur Food Res Technol 226, 1513–1524 (2008). https://doi.org/10.1007/s00217-007-0683-z
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DOI: https://doi.org/10.1007/s00217-007-0683-z