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Journal of Clinical Laboratory Analysis logoLink to Journal of Clinical Laboratory Analysis
. 2009 May 19;23(3):145–151. doi: 10.1002/jcla.20307

Checklist for optimization and validation of real‐time PCR assays

Marijke Raymaekers 1,, Rita Smets 1, Brigitte Maes 1, Reinoud Cartuyvels 1
PMCID: PMC6649018  PMID: 19455629

Abstract

Real‐time polymerase chain reaction (PCR) is a frequently used technique in molecular diagnostics. To date, practical guidelines for the complete process of optimization and validation of commercial and in‐house developed molecular diagnostic methods are scare. Therefore, we propose a practical guiding principle for the optimization and validation of real‐time PCR assays. Based on literature, existing guidelines, and personal experience, we created a checklist that can be used in different steps of the development and validation process of commercial and in‐house developed real‐time PCR assays. Furthermore, determination of target values and reproducibility of internal quality controls are included, which allows a statistical follow‐up of the performance of the assay. Recently, we used this checklist for the development of various qualitative and quantitative assays for microbiological and hematological applications, for which accreditation according to ISO 15189:2007 was obtained. In our experience, the use of the proposed guidelines leads to a more efficient and standardized optimization and validation. Ultimately, this results in reliable and robust molecular diagnostics. The proposed checklist is independent of environment, equipment, and specific applications and can be used in other laboratories. A worldwide consensus on this kind of checklist should be aimed at. J. Clin. Lab. Anal. 23:145–151, 2009. © 2009 Wiley‐Liss, Inc.

Keywords: real‐time PCR, checklist, molecular diagnostics, optimization, validation

REFERENCES

  • 1. Saiki RK, Scharf S, Faloona F, et al. Enzymatic amplification of beta‐globin genomic sequences and restriction site analysis for diagnosis of sickle cell anemia. Science 1985;230:1350–1354. [DOI] [PubMed] [Google Scholar]
  • 2. Mullis KB, Faloona FA. Specific synthesis of DNA in vitro via a polymerase‐catalyzed chain reaction. Methods Enzymol 1987;155:335–350. [DOI] [PubMed] [Google Scholar]
  • 3. Higuchi R, Dollinger G, Walsh PS, et al. Simultaneous amplification and detection of specific DNA sequences. Biotechnology (N Y) 1992;10:413–417. [DOI] [PubMed] [Google Scholar]
  • 4. Higuchi R, Fockler C, Dollinger G, et al. Kinetic PCR analysis: Real‐time monitoring of DNA amplification reactions. Biotechnology (N Y) 1993;11:1026–1030. [DOI] [PubMed] [Google Scholar]
  • 5. Holland PM, Abramson RD, Watson R, et al. Detection of specific polymerase chain reaction product by utilizing the 5′—3′ exonuclease activity of Thermus aquaticus DNA polymerase. Proc Natl Acad Sci USA 1991;88:7276–7280. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 6. Lee LG, Connell CR, Bloch W. Allelic discrimination by nick‐translation PCR with fluorogenic probes. Nucleic Acids Res 1993;21:3761–3766. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 7. Livak KJ, Flood SJ, Marmaro J, et al. Oligonucleotides with fluorescent dyes at opposite ends provide a quenched probe system useful for detecting PCR product and nucleic acid hybridization. PCR Methods Appl 1995;4:357–362. [DOI] [PubMed] [Google Scholar]
  • 8. Csako G. Present and future of rapid and/or high‐throughput methods for nucleic acid testing. Clin Chim Acta 2006;363:6–31. [DOI] [PubMed] [Google Scholar]
  • 9. NCCLS . Quantitative molecular methods for infectious diseases: Approved guidelines. Document MM6‐A. Wayne, PA: NCCLS; 2003; 1–69. [Google Scholar]
  • 10. Gunson RN, Collins TC, Carman WF. Practical experience of high throughput real time PCR in the routine diagnostic virology setting. J Clin Virol 2006;35:355–367. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 11. Sloan LM. Real‐time PCR in clinical microbiology: Verification, validation, and contamination control. Clin Microb Newsletter 2007;29:87–95. [Google Scholar]
  • 12. Rabenau HF, Kessler H, Kortenbusch M, et al. Verification and validation of diagnostic laboratory tests in clinical virology. J Clin Virol 2007;40:93–98. [DOI] [PubMed] [Google Scholar]
  • 13. Organization Economic Cooperation and Development (OECD) , OECD guidelines for quality assurance in molecular genetic testing; http://www.oecd.org/dataoecd/43/38839788.pdf.
  • 14. Amos J, Feldman G, Wayne W. Technical standards and guidelines for CFTR mutation testing. 2006.
  • 15. College of American Pathologists. Laboratory accreditation program checklist , Laboratory accreditation program, accreditation checklists. 2008.
  • 16. Ginzinger DG. Gene quantification using real‐time quantitative PCR: An emerging technology hits the mainstream. Exp Hematol 2002;30:503–512. [DOI] [PubMed] [Google Scholar]
  • 17. Singh SK, Koshkin AA, Wengel J, Nielsen P. LNA (locked nucleic acids): Synthesis and high‐affinity nucleic acid recognition. Chem Commun 1998;4:455–456. [Google Scholar]
  • 18. Braasch DA, Corey DR. Locked nucleic acid (LNA): Fine‐tuning the recognition of DNA and RNA. Chem Biol 2001;8:1–7. [DOI] [PubMed] [Google Scholar]
  • 19. Kutyavin IV, Afonina IA, Mills A, et al. 3′‐Minor groove binder‐DNA probes increase sequence specificity at PCR extension temperatures. Nucleic Acids Res 2000;28:655–661. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 20. Tyagi S, Bratu DP, Kramer FR. Multicolor molecular beacons for allele discrimination. Nat Biotechnol 1998;16:49–53. [DOI] [PubMed] [Google Scholar]
  • 21. Tyagi S, Kramer FR. Molecular beacons: Probes that fluoresce upon hybridization. Nat Biotechnol 1996;14:303–308. [DOI] [PubMed] [Google Scholar]
  • 22. Caplin BE, Bernard RPRPS, Wittwer CT. Lightcycler hybridization probes—the most direct way to monitor PCR amplification and mutation detection. Biochemistry 1999;1:5–8. [Google Scholar]
  • 23. Kusser W. Use of self‐quenched, fluorogenic LUX primers for gene expression profiling. Methods Mol Biol 2006;335:115–133. [DOI] [PubMed] [Google Scholar]
  • 24. Svanvik N, WEstman G, Wang D, et al. Light‐up probes: Thiazole orange‐conjugated peptide nucleic acid for detection of target nucleic acid in homogeneous solution. Anal Biochem 2000;281:26–35. [DOI] [PubMed] [Google Scholar]
  • 25. Li Q, Luan G, Guo Q, et al. A new class of homogeneous nucleic acid probes based on specific displacement hybridization. Nucleic Acids Res 2002;30:E5. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 26. Kubista M, Andrade JM, Williamson M, et al. The real‐time polymerase chain reaction. Mol Aspects Med 2006;27:95–125. [DOI] [PubMed] [Google Scholar]
  • 27. Arya M, Shergill IS, Williamson M, et al. Basic principles of real‐time quantitative PCR. Expert Rev Mol Diagn 2005;5:209–219. [DOI] [PubMed] [Google Scholar]
  • 28. Aslanzadeh J. Preventing PCR amplification carryover contamination in a clinical laboratory. Ann Clin Lab Sci 2004;34:389–396. [PubMed] [Google Scholar]
  • 29. Bustin SA, Nolan T. Pitfalls of quantitative real‐time reverse‐transcription polymerase chain reaction. J Biomol Tech 2004;15:155–166. [PMC free article] [PubMed] [Google Scholar]
  • 30. Mackay IM. Real‐time PCR in the microbiology laboratory. Clin Microbiol Infect 2004;10:190–212. [DOI] [PubMed] [Google Scholar]
  • 31. Tan BH, Lim EA, Liaw JC, et al. Diagnostic value of real‐time capillary thermal cycler in virus detection. Expert Rev Mol Diagn 2004;4:219–230. [DOI] [PubMed] [Google Scholar]
  • 32. Muller MC, Erben P, Saglio G, et al. Harmonization of BCR‐ABL mRNA quantification using a uniform multifunctional control plasmid in 37 international laboratories. Leukemia 2007. [DOI] [PubMed] [Google Scholar]
  • 33. Silvy M, Mancini J, Thirion X, et al. Evaluation of real‐time quantitative PCR machines for the monitoring of fusion gene transcripts using the Europe against cancer protocol. Leukemia 2005;19:305–307. [DOI] [PubMed] [Google Scholar]
  • 34. Hyndman DL, Mitsuhashi M. PCR primer design. Methods Mol Biol 2003;226:81–88. [DOI] [PubMed] [Google Scholar]
  • 35.AppliedBiosystems. Primer Express Software; http://primer‐express.software.informer.com
  • 36. Rozen S, Skaletsky HJ. Primer3 on the WWW for general users and for biologist programmers In: S Krawetz, S Misener, editors. Bioinformatics Methods and Protocols: Methods in Molecular Biology. Totowa, NJ: Humana Press; 2000, p 365–386. [DOI] [PubMed] [Google Scholar]
  • 37. Rychlik P, Rychlik W. Oligo. 7 primer analysis software. Methods Mol Biol 2007;402:35–60. [DOI] [PubMed] [Google Scholar]
  • 38. McConlogue L, Brow MA, Innis MA. Structure‐independent DNA amplification by PCR using 7‐deaza‐2′‐deoxyguanosine. Nucleic Acids Res 1988;16:9869. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 39. Saiki RK. The design and optimization of the PCR In: HA Erlich, editor. PCR Technology: Principles and Applications for DNA Amplification. New York: Stockton Press; 1989, p 7–22. [Google Scholar]
  • 40. Brooks EM, Sheflin LG, Spaulding SW. Secondary structure in the 3' UTR of EGF and the choice of reverse transcriptases affect the detection of message diversity by RT‐PCR. Biotechniques 1995;19:806–812, 814–815. [PubMed] [Google Scholar]
  • 41. Suggs SV, Hirose T, Miyake EH, Kawashima MJ, Johnson KI, Wallace RB. Using purified genes In: DD Brown, editor. ICN‐UCLA Symposium on Developmental Biology, Vol. 23 New York: Academic Press; 1981, p 683. [Google Scholar]
  • 42. Bolton ET, Mc Carthy B. A general method for the isolation of RNA complementary to DNA. Proc Natl Acad Sci USA 1962;48:1390–1397. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 43. Breslauer KJ, Frank R, Blocker H, et al. Predicting DNA duplex stability from the base sequence. Proc Natl Acad Sci USA 1986;83:3746–3750. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 44. Freier SM, Kierzek R, Jaeger JA, et al. Improved free‐energy parameters for predictions of RNA duplex stability. Proc Natl Acad Sci USA 1986;83:9373–9377. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 45. Mitsuhashi M. Technical report: Part 1. Basic requirements for designing optimal oligonucleotide probe sequences. J Clin Lab Anal 1996;10:277–284. [DOI] [PubMed] [Google Scholar]
  • 46. Rychlik W, Rhoads RE. A computer program for choosing optimal oligonucleotides for filter hybridization, sequencing and in vitro amplification of DNA. Nucleic Acids Res 1989;17:8543–8551. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 47. Wittwer CT, Herrmann MG, Moss AA, et al. Continuous fluorescence monitoring of rapid cycle DNA amplification. Biotechniques 1997;22:130–131, 134–138. [DOI] [PubMed] [Google Scholar]
  • 48. Mitsuhashi M. Technical report: Part 2. Basic requirements for designing optimal PCR primers. J Clin Lab Anal 1996;10:285–293. [DOI] [PubMed] [Google Scholar]
  • 49. Toouli CD, Turner DR, Grist SA, et al. The effect of cycle number and target size on polymerase chain reaction amplification of polymorphic repetitive sequences. Anal Biochem 2000;280:324–326. [DOI] [PubMed] [Google Scholar]
  • 50. Simonsson T, Pecinka P, Kubista M. DNA tetraplex formation in the control region of c‐myc. Nucleic Acids Res 1998;26:1167–1172. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 51. Bej AK, Mahbubani MH, Atlas RM. Amplification of nucleic acids by polymerase chain reaction (PCR) and other methods and their applications. Crit Rev Biochem Mol Biol 1991;26:301–334. [DOI] [PubMed] [Google Scholar]
  • 52. Newton CR, Graham A. PCR. Oxford, UK: BIOS Scientific Publishers; 1994. [Google Scholar]
  • 53.Compliance, C.s.C.L.R.A.g.t.C., Washing G‐2 Reports. 1997. Washington.
  • 54. Espy MJ, UHL J, Sloan L, et al. Real‐time PCR in clinical microbiology: Applications for routine laboratory testing. Clin Microbiol Rev 2006;19:165–256. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 55. Radstrom P, Knutsson R, Wolffs P, et al. Pre‐PCR processing: Strategies to generate PCR‐compatible samples. Mol Biotechnol 2004;26:133–146. [DOI] [PubMed] [Google Scholar]
  • 56. Hoorfar J, Wolffs P, Radstrom P. Diagnostic PCR: Validation and sample preparation are two sides of the same coin. APMIS 2004;112:808–814. [DOI] [PubMed] [Google Scholar]
  • 57. Bustin SA. Absolute quantification of mRNA using real‐time reverse transcription polymerase chain reaction assays. J Mol Endocrinol 2000;25:169–193. [DOI] [PubMed] [Google Scholar]
  • 58. Livak KJ, Schmittgen TD. Analysis of relative gene expression data using real‐time quantitative PCR and the 2(‐Delta Delta C(T)) method. Methods 2001;25:402–408. [DOI] [PubMed] [Google Scholar]
  • 59. Pfaffl MW. A new mathematical model for relative quantification in real‐time RT‐PCR. Nucleic Acids Res 2001;29:e45. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 60. Pfaffl MW, Horgan GW, Dempfle L. Relative expression software tool (REST) for group‐wise comparison and statistical analysis of relative expression results in real‐time PCR. Nucleic Acids Res 2002;30:e36. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 61. Gibbs PJ, Cameron C, Tan LC, et al. House keeping genes and gene expression analysis in transplant recipients: A note of caution. Transpl Immunol 2003;12:89–97. [DOI] [PubMed] [Google Scholar]
  • 62. Pfaffl MW, Tichopad A, Prgomet C, et al. Determination of stable housekeeping genes, differentially regulated target genes and sample integrity: BestKeeper—Excel‐based tool using pair‐wise correlations. Biotechnol Lett 2004;26:509–515. [DOI] [PubMed] [Google Scholar]
  • 63. Huggett J, Dheda K, Bustin S, et al. Real‐time RT‐PCR normalisation; Strategies and considerations. Genes Immun 2005;6:279–284. [DOI] [PubMed] [Google Scholar]
  • 64.NCBI, http://www.ncbi.nlm.gov/blast/Blast.cgi.
  • 65. Wheeler DL, Barrett T, Benson DA, et al. Database resources of the National Center for Biotechnology Information. Nucleic Acids Res 2007;35:D5–D12. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 66. Karlin S, Altschul SF. Methods for assessing the statistical significance of molecular sequence features by using general scoring schemes. Proc Natl Acad Sci USA 1990;87:2264–2268. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 67. Altschul SF, Gish W, Miller W, et al. Basic local alignment search tool. J Mol Biol 1990;215:403–410. [DOI] [PubMed] [Google Scholar]
  • 68. Rasmussen R. Quantification on the LightCycler instrument In: Meuer S, Wittwer C, Nakagawara K, editors. Rapid Cycle Real‐Time PCR: Methods and Applications. Heidelberg: Springer Press; 2001, p 21–34. [Google Scholar]
  • 69. Wong ML, Medrano JF. Real‐time PCR for mRNA quantitation. Biotechniques 2005;39:1–11. [DOI] [PubMed] [Google Scholar]
  • 70. Yuan JS, Reed A, Chen F, et al. Statistical analysis of real‐time PCR data. Bioinformatics 2006;7:85. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 71. Liu W, Saint DA. A new quantitative method of real time reverse transcription polymerase chain reaction assay based on simulation of polymerase chain reaction kinetics. Anal Biochem 2002;302:52–59. [DOI] [PubMed] [Google Scholar]
  • 72. Tichopad A, Dzidic A, Pfaffl MW. Improving quantitative real‐time RT‐PCR reproducibility by boosting primer‐linked amplification efficiency. Biotechnol Lett 2002;24:2053–2056. [Google Scholar]
  • 73. Tichopad A, Didier A, W PM. Inhibition of real‐time RT–PCR quantification due to tissue‐specific contaminants. Mol Cell Probes 2004;18:45–50. [DOI] [PubMed] [Google Scholar]
  • 74. Rutledge RG. Sigmoidal curve‐fitting redefines quantitative real‐time PCR with the prospective of developing automated high‐throughput applications. Nucleic Acids Res 2004;32:e178. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 75. Tichopad A, Dilger M, Schwarz G, et al. Standardized determination of real‐time PCR effciency from a single reaction set‐up. Nucleic Aids Res 2003;31:e122. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 76. Cikos S, Bukovska A, Koppel J. Relative quantification of mRNA: Comparison of methods currently used for real‐time PCR data analysis. Mol Biol 2007;8:113. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 77. Kontanis EJ, Reed FA. Evaluation of real‐time PCR amplification efficiencies to detect PCR inhibitors. J Forensic Sci 2006;51:795–804. [DOI] [PubMed] [Google Scholar]
  • 78. Snedecor G, Cochran W. Statistical Methods, 7th edition Iowa: The Iowa State University Press; 1980. [Google Scholar]
  • 79. CLSI , CLSI document MM3‐A2.
  • 80. CLSI , CLSI document CS2.
  • 81.Westgard, Tietz textbook of clinical chemistry. 1999.
  • 82. CLSI , CLSI document M14A.
  • 83. CLSI , CLSI document GP29A.
  • 84. Branford S, Cross NC, Hochhaus A, et al. Rationale for the recommendations for harmonizing current methodology for detecting BCR‐ABL transcripts in patients with chronic myeloid leukaemia. Leukemia 2006;20:1925–1930. [DOI] [PubMed] [Google Scholar]
  • 85. Hughes T, Deininger M, Hochhaus A, et al. Monitoring CML patients responding to treatment with tyrosine kinase inhibitors: Review and recommendations for harmonizing current methodology for detecting BCR‐ABL transcripts and kinase domain mutations and for expressing results. Blood 2006;108:28–37. [DOI] [PMC free article] [PubMed] [Google Scholar]

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