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Hu Z, Whitney D, Anderson JR, Cao M, Ho C, Choi Y, Huang J, Frink R, Smith KP, Monroe R, Kennedy GC, Walsh PS. Analytical performance of a bronchial genomic classifier. BMC Cancer 2016; 16:161. [PMID: 26920854 PMCID: PMC4768333 DOI: 10.1186/s12885-016-2153-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Accepted: 02/09/2016] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND The current standard practice of lung lesion diagnosis often leads to inconclusive results, requiring additional diagnostic follow up procedures that are invasive and often unnecessary due to the high benign rate in such lesions (Chest 143:e78S-e92, 2013). The Percepta bronchial genomic classifier was developed and clinically validated to provide more accurate classification of lung nodules and lesions that are inconclusive by bronchoscopy, using bronchial brushing specimens (N Engl J Med 373:243-51, 2015, BMC Med Genomics 8:18, 2015). The analytical performance of the Percepta test is reported here. METHODS Analytical performance studies were designed to characterize the stability of RNA in bronchial brushing specimens during collection and shipment; analytical sensitivity defined as input RNA mass; analytical specificity (i.e. potentially interfering substances) as tested on blood and genomic DNA; and assay performance studies including intra-run, inter-run, and inter-laboratory reproducibility. RESULTS RNA content within bronchial brushing specimens preserved in RNAprotect is stable for up to 20 days at 4 °C with no changes in RNA yield or integrity. Analytical sensitivity studies demonstrated tolerance to variation in RNA input (157 ng to 243 ng). Analytical specificity studies utilizing cancer positive and cancer negative samples mixed with either blood (up to 10 % input mass) or genomic DNA (up to 10 % input mass) demonstrated no assay interference. The test is reproducible from RNA extraction through to Percepta test result, including variation across operators, runs, reagent lots, and laboratories (standard deviation of 0.26 for scores on > 6 unit scale). CONCLUSIONS Analytical sensitivity, analytical specificity and robustness of the Percepta test were successfully verified, supporting its suitability for clinical use.
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Affiliation(s)
- Zhanzhi Hu
- Veracyte, Inc., 6000 Shoreline Ct., Suite 300, South San Francisco, CA, 94080, USA.
| | - Duncan Whitney
- Veracyte, Inc., 6000 Shoreline Ct., Suite 300, South San Francisco, CA, 94080, USA.
| | - Jessica R Anderson
- Veracyte, Inc., 6000 Shoreline Ct., Suite 300, South San Francisco, CA, 94080, USA.
| | - Manqiu Cao
- Veracyte, Inc., 6000 Shoreline Ct., Suite 300, South San Francisco, CA, 94080, USA.
| | - Christine Ho
- Veracyte, Inc., 6000 Shoreline Ct., Suite 300, South San Francisco, CA, 94080, USA.
| | - Yoonha Choi
- Veracyte, Inc., 6000 Shoreline Ct., Suite 300, South San Francisco, CA, 94080, USA.
| | - Jing Huang
- Veracyte, Inc., 6000 Shoreline Ct., Suite 300, South San Francisco, CA, 94080, USA.
| | - Robert Frink
- Veracyte, Inc., 6000 Shoreline Ct., Suite 300, South San Francisco, CA, 94080, USA.
| | - Kate Porta Smith
- Veracyte, Inc., 6000 Shoreline Ct., Suite 300, South San Francisco, CA, 94080, USA.
| | - Robert Monroe
- Veracyte, Inc., 6000 Shoreline Ct., Suite 300, South San Francisco, CA, 94080, USA.
| | - Giulia C Kennedy
- Veracyte, Inc., 6000 Shoreline Ct., Suite 300, South San Francisco, CA, 94080, USA.
| | - P Sean Walsh
- Veracyte, Inc., 6000 Shoreline Ct., Suite 300, South San Francisco, CA, 94080, USA.
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Lanjouw E, Ouburg S, de Vries HJ, Stary A, Radcliffe K, Unemo M. Background review for the '2015 European guideline on the management of Chlamydia trachomatis infections'. Int J STD AIDS 2015:0956462415618838. [PMID: 26608578 DOI: 10.1177/0956462415618838] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
SummaryChlamydia trachomatis infections are major public health concerns globally. Of particular grave concern is that the majority of persons with anogenital Chlamydia trachomatis infections are asymptomatic and accordingly not aware of their infection, and this silent infection can subsequently result in severe reproductive tract complications and sequelae. The current review paper provides all background, evidence base and discussions for the 2015 European guideline on the management of Chlamydia trachomatis infections (Lanjouw E, et al. Int J STD AIDS 2015). Comprehensive information and recommendations are included regarding the diagnosis, treatment and prevention of anogenital, pharyngeal and conjunctival Chlamydia trachomatis infections in European countries. However, Chlamydia trachomatis also causes the eye infection trachoma, which is not a sexually transmitted infection. The 2015 European Chlamydia trachomatis guideline provides up-to-date guidance regarding broader indications for testing and treatment of Chlamydia trachomatis infections; clearer recommendation of using validated nucleic acid amplification tests only for diagnosis; advice on (repeated) Chlamydia trachomatis testing; recommendation of increased testing to reduce the incidence of pelvic inflammatory disease and prevent exposure to infection and recommendations to identify, verify and report Chlamydia trachomatis variants. Improvement of access to testing, test performance, diagnostics, antimicrobial treatment and follow-up of Chlamydia trachomatis patients are crucial to control its spread.
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Affiliation(s)
- E Lanjouw
- Department of Dermatology, Erasmus Medical Center, Rotterdam, The Netherlands
| | - S Ouburg
- Laboratory of Immunogenetics, Department of Medical Microbiology and Infection Control, VU University Medical Center, Amsterdam, The Netherlands
| | - H J de Vries
- Department of Dermatology, Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands STI Outpatient Clinic, Infectious Disease Cluster, Health Service Amsterdam, Amsterdam, The Netherlands Center for Infection and Immunology Amsterdam (CINIMA), Academic Medical Center (AMC), University of Amsterdam, Amsterdam, The Netherlands
| | - A Stary
- Outpatients' Centre for Infectious Venereodermatological Diseases, Vienna, Austria
| | - K Radcliffe
- University Hospital Birmingham Foundation NHS Trust, Birmingham, UK
| | - M Unemo
- WHO Collaborating Center for Gonorrhoea and other Sexually Transmitted Infections, National Reference Laboratory for Pathogenic Neisseria, Department of Laboratory Medicine, Microbiology, Faculty of Medicine and Health, Örebro University, Örebro, Sweden
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Ambasta A, Carson J, Church DL. The use of biomarkers and molecular methods for the earlier diagnosis of invasive aspergillosis in immunocompromised patients. Med Mycol 2015; 53:531-57. [DOI: 10.1093/mmy/myv026] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2015] [Accepted: 04/08/2015] [Indexed: 12/15/2022] Open
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Speicher DJ, Johnson NW. Comparison of salivary collection and processing methods for quantitative HHV-8 detection. Oral Dis 2013; 20:720-8. [PMID: 24134156 DOI: 10.1111/odi.12196] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2013] [Accepted: 09/27/2013] [Indexed: 11/28/2022]
Abstract
OBJECTIVES Saliva is a proved diagnostic fluid for the qualitative detection of infectious agents, but the accuracy of viral load determinations is unknown. Stabilising fluids impede nucleic acid degradation, compared with collection onto ice and then freezing, and we have shown that the DNA Genotek P-021 prototype kit (P-021) can produce high-quality DNA after 14 months of storage at room temperature. Here we evaluate the quantitative capability of 10 collection/processing methods. METHODS Unstimulated whole mouth fluid was spiked with a mixture of HHV-8 cloned constructs, 10-fold serial dilutions were produced, and samples were extracted and then examined with quantitative PCR (qPCR). Calibration curves were compared by linear regression and qPCR dynamics. RESULTS All methods extracted with commercial spin columns produced linear calibration curves with large dynamic range and gave accurate viral loads. Ethanol precipitation of the P-021 does not produce a linear standard curve, and virus is lost in the cell pellet. DNA extractions from the P-021 using commercial spin columns produced linear standard curves with wide dynamic range and excellent limit of detection. CONCLUSION When extracted with spin columns, the P-021 enables accurate viral loads down to 23 copies μl(-1) DNA. The quantitative and long-term storage capability of this system makes it ideal for study of salivary DNA viruses in resource-poor settings.
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Affiliation(s)
- D J Speicher
- School of Dentistry and Oral Health, Griffith University, Gold Coast, Qld, Australia; Molecular Basis of Disease Research Program, Griffith Health Institute, Griffith University, Gold Coast, Qld, Australia; Population & Social Health Research Program (Population Oral Health), Griffith Health Institute, Griffith University, Gold Coast, Qld, Australia
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Bromhead C, Miller A, Jones M, Whiley D. Comparison of the cobas 4800 CT/NG test with culture for detecting Neisseria gonorrhoeae in genital and nongenital specimens in a low-prevalence population in New Zealand. J Clin Microbiol 2013; 51:1505-9. [PMID: 23467604 PMCID: PMC3647945 DOI: 10.1128/jcm.03223-12] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2012] [Accepted: 03/01/2013] [Indexed: 11/20/2022] Open
Abstract
To assess the clinical utility of replacing microbial culture for Neisseria gonorrhoeae with a nucleic acid amplification test (NAAT), we compared N. gonorrhoeae culture with the cobas 4800 CT/NG test for 18,247 urogenital and 666 nongenital samples. For urogenital specimens, the sensitivity, specificity, and positive and negative predictive values of the cobas N. gonorrhoeae PCR were 98.7%, 100%, 95.6%, and 100%, respectively, and for nongenital specimens, the values were 100%, 99.8%, 92.9%, and 100%, respectively. In our test population, 37% (10,185) of patients tested over the study period were screened for C. trachomatis by PCR but were not screened for gonorrhea by culture. Of these, 43 were N. gonorrhoeae positive by PCR and therefore went undiagnosed. The cobas 4800 CT/NG test diagnosed 33% (n = 30) more urogenital and 25% (n = 3) more rectal gonorrhea infections than culture and, based on the above performance indicators, does not require supplementary testing for urogenital or rectal specimens. The ability to test noninvasive specimens (such as urine and self-taken vulvovaginal swabs) for N. gonorrhoeae will enable more patients to be screened for infection, thus offering significant positive public health benefits.
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Walsh PS, Wilde JI, Tom EY, Reynolds JD, Chen DC, Chudova DI, Pagan M, Pankratz DG, Wong M, Veitch J, Friedman L, Monroe R, Steward DL, Lupo MA, Lanman RB, Kennedy GC. Analytical performance verification of a molecular diagnostic for cytology-indeterminate thyroid nodules. J Clin Endocrinol Metab 2012; 97:E2297-306. [PMID: 23087323 DOI: 10.1210/jc.2012-1923] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
OBJECTIVE Our objective was to verify the analytical performance of the Afirma gene expression classifier (GEC) in the classification of cytologically indeterminate thyroid nodule fine-needle aspirates (FNAs). DESIGN Analytical performance studies were designed to characterize the stability of RNA in FNAs during collection and shipment, analytical sensitivity as applied to input RNA concentration and malignant/benign FNA mixtures, analytical specificity (i.e. potentially interfering substances) as tested on blood and genomic DNA, and assay performance studies including intra-nodule, intraassay, inter-assay, and inter-laboratory reproducibility. RESULTS RNA content within FNAs preserved in FNAProtect is stable for up to 6 d at room temperature with no changes in RNA yield (P = 0.58) or quality (P = 0.56). FNA storage and shipping temperatures were found to have no significant effect on GEC scores (P = 0.55) or calls (100% concordance). Analytical sensitivity studies demonstrated tolerance to variation in RNA input (5-25 ng) and to the dilution of malignant FNA material down to 20%. Analytical specificity studies using malignant samples mixed with blood (up to 83%) and genomic DNA (up to 30%) demonstrated negligible assay interference with respect to false-negative calls, although benign FNA samples mixed with relatively high proportions of blood demonstrated a potential for false-positive calls. The test is reproducible from extraction through GEC result, including variation across operators, runs, reagent lots, and laboratories (sd of 0.158 for scores on a >6 unit scale). CONCLUSIONS Analytical sensitivity, analytical specificity, robustness, and quality control of the GEC were successfully verified, indicating its suitability for clinical use.
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Affiliation(s)
- P Sean Walsh
- Veracyte, Inc., South San Francisco, California 94080, USA.
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Speicher DJ, Johnson NW. Detection of human herpesvirus 8 by quantitative polymerase chain reaction: development and standardisation of methods. BMC Infect Dis 2012; 12:210. [PMID: 22963082 PMCID: PMC3490733 DOI: 10.1186/1471-2334-12-210] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2012] [Accepted: 06/28/2012] [Indexed: 11/25/2022] Open
Abstract
Background Human herpesvirus 8 (HHV-8), the aetiological agent of Kaposi’s sarcoma (KS), multicentric Castleman’s disease (MCD), and primary effusion lymphoma (PEL) is rare in Australia, but endemic in Sub-Saharan Africa, parts of South-east Asia and Oceania. While the treatment of external KS lesions can be monitored by clinical observation, the internal lesions of KS, MCD and PEL require extensive and expensive internal imaging, or autopsy. In patients with MCD and PEL, if HHV-8 viraemia is not reduced quickly, ~50% die within 24 months. HHV-8 qPCR is a valuable tool for monitoring HHV-8 viraemia, but is not available in many parts of the world, including those with high prevalence of KS and HHV-8. Methods A new molecular facility with stringent three-phase workflow was established, adhering to NPAAC and CLSI guidelines. Three fully validated quantitative assays were developed: two for detection and quantification of HHV-8; one for GAPDH, necessary for normalisation of viral loads in tissue and peripheral blood. Results The HHV-8 ORF73 and ORF26 qPCR assays were 100% specific. All qPCR assays, displayed a broad dynamic range (102 to 1010 copies/μL TE Buffer) with a limit of detection of 4.85x103, 5.61x102, and 2.59x102 copies/μL TE Buffer and a limit of quantification of 4.85x103, 3.01x102, and 1.38x102 copies/μL TE Buffer for HHV-8 ORF73, HHV-8 ORF26, and GAPDH respectively. The assays were tested on a panel of 35 KS biopsies from Queensland. All were HHV-8 qPCR positive with average viral load of 2.96x105 HHV-8 copies/μL DNA extract (range: 4.37x103 to 1.47x106 copies/μL DNA extract): When normalised these equate to an average viral load of 2.44x104 HHV-8 copies/103 cells (range: 2.20x102 to 7.38x105 HHV-8 copies/103 cells). Conclusions These are the first fully optimised, validated and MIQE compliant HHV-8 qPCR assays established in Australia. They worked well for qualitative detection of HHV-8 in archival tissue, and are well-suited for quantitative detection in whole blood. They are now available for research, for clinical diagnosis of HHV-8 infection, and for monitoring treatment efficacy.
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Affiliation(s)
- David J Speicher
- School of Dentistry and Oral Health, Griffith University, Queensland, Australia.
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8
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Shang D, Hughes SA, Horner M, Bruce MJ, Dong Y, Carey I, Suddle AR, Agarwal K, Harrison PM, Atkins M. Development and validation of an efficient in-house real-time reverse transcription polymerase chain reaction assay for the quantitative detection of serum hepatitis delta virus RNA in a diverse South London population. J Virol Methods 2012; 184:55-62. [DOI: 10.1016/j.jviromet.2012.05.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2011] [Revised: 05/01/2012] [Accepted: 05/10/2012] [Indexed: 12/14/2022]
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9
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Naderi M, Paryan M, Azadmanesh K, Rafatpanah H, Rezvan H, Mirab Samiee S. Design and development of a quantitative real time PCR assay for monitoring of HTLV-1 provirus in whole blood. J Clin Virol 2012; 53:302-7. [PMID: 22306271 DOI: 10.1016/j.jcv.2011.12.033] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2011] [Revised: 12/27/2011] [Accepted: 12/29/2011] [Indexed: 11/27/2022]
Abstract
BACKGROUND Proviral load quantification of human T-lymphotropic virus type 1 (HTLV-1) is an essential marker for disease progression. Therefore, accurate and precise quantification of the virus is important. However, many articles published about detection and quantification of HTLV-1 virus neither reported any databank for the pre-validation of their primer and probe sequences nor stressed on its importance. Consequently, this failure may cause proviral load measurement variations of different HTLV-1 strains. OBJECTIVE The aim of this study was to develop a TaqMan assay for HTLV-1 proviral load quantification which is based on a conserved region of tax gene with minimal sequence variability. STUDY DESIGN For the purpose of finding the most conserved region of tax gene, all the HTLV-1 Gene Bank records including tax gene sequence (524 records by December 2009) were aligned in order to design on the most conserved region of this gene. The specificity, sensitivity, inter and intra assay and the dynamic range of the assay were experimentally determined by their respective methodology. RESULT The assay has a dynamic range of 10-10(7) HTLV-1 plasmid DNA/rxn (reaction) and the limit of detection (LOD) less than 10 copies/rxn. The assay gave coefficient of variation (CV) for the Ct values of less than 1% and 4.8% for intra and inter assay, respectively. Clinical sensitivity and specificity were determined to be 97.8% and 100%, respectively. CONCLUSION This TaqMan assay is able to reliably quantify proviral load due to the fact that it has been designed on a conserved region of HTLV-1 tax gene with minimal sequence variability.
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Affiliation(s)
- Mahmood Naderi
- Department of Biotechnology, Tarbiat Modares University, Tehran, Iran
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10
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Use of Commercial Amplification Tests in the Clinical Microbiology Laboratory: Test Selection and Quality Assurance. Mol Microbiol 2011. [DOI: 10.1128/9781555816834.ch6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Lanjouw E, Ossewaarde JM, Stary A, Boag F, van der Meijden WI. 2010 European guideline for the management of Chlamydia trachomatis infections. Int J STD AIDS 2011; 21:729-37. [PMID: 21187352 DOI: 10.1258/ijsa.2010.010302] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
This guideline aims to provide comprehensive information regarding the management of infections caused by Chlamydia trachomatis in European countries. The recommendations contain important information for physicians and laboratory staff working with sexually transmitted infections (STIs) and/or STI-related issues. Individual European countries may be required to make minor national adjustments to this guideline as some of the tests or specific local data may not be accessible, or because of specific laws.
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Affiliation(s)
- E Lanjouw
- Department of Dermatology, Erasmus MC, Rotterdam, Netherlands.
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12
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Bergallo M, Terlizzi ME, Astegiano S, Ciotti M, Babakir-Mina M, Perno CF, Cavallo R, Costa C. Real time PCR TaqMan assays for detection of polyomaviruses KIV and WUV in clinical samples. J Virol Methods 2009; 162:69-74. [PMID: 19646480 PMCID: PMC7119675 DOI: 10.1016/j.jviromet.2009.07.016] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2009] [Revised: 07/14/2009] [Accepted: 07/21/2009] [Indexed: 11/23/2022]
Abstract
Recently, polyomaviruses KI and WU were identified in the airways of patients with acute respiratory symptoms. The epidemiology and pathogenesis of these two viruses are not fully understood, and the development of molecular assays, such as Real Time PCR, was useful for examining their biology and role in different clinical syndromes. The evaluation of different target regions for the amplification of polyomaviruses KI and WU, comparing published primer/probe sets and sets designed in the laboratory is described and was used for testing 175 clinical specimens (84 stools and 91 tonsils). The results showed that the laboratory designs were more sensitive for the detection of polyomaviruses KI and WU DNA in clinical samples. The choice of the primer/probe set, and primarily of the region for amplification, may be relevant for understanding the pathogenic role of viruses such as polyomaviruses KI and WU.
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Affiliation(s)
- Massimiliano Bergallo
- Department of Public Health and Microbiology, Virology Unit, University of Turin, Via Santena 9, 10126 Turin, Italy
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Jennings L, Van Deerlin VM, Gulley ML. Recommended principles and practices for validating clinical molecular pathology tests. Arch Pathol Lab Med 2009; 133:743-55. [PMID: 19415949 DOI: 10.5858/133.5.743] [Citation(s) in RCA: 145] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/12/2008] [Indexed: 11/06/2022]
Abstract
CONTEXT The use of DNA- and RNA-based tests continues to grow for applications as varied as inherited disease, infectious disease, cancer, identity testing, human leukocyte antigen typing, and pharmacogenetics. Progress is driven in part by the huge growth in knowledge about the molecular basis of disease coupled with advancements in technologic capabilities. In addition to requirements for clinical utility, every molecular test also may have limitations that must be carefully considered before clinical implementation. Analytic and clinical performance characteristics as well as test limitations are established and documented through the process of test validation. OBJECTIVE To describe the established principles of test validation, along with relevant regulations in the United States, in order to provide a rational approach to introducing molecular tests into the clinical laboratory. DATA SOURCES PubMed review of published literature, published guidelines, and online information from national and international professional organizations. CONCLUSIONS These resources and recommendations provide a framework for validating clinical tests.
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Affiliation(s)
- Lawrence Jennings
- Department of Pathology and Laboratory Medicine, Children's Memorial Hospital, Chicago, Illinois, USA
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Fryer JF, Minor PD. Standardisation of nucleic acid amplification assays used in clinical diagnostics: A report of the first meeting of the SoGAT Clinical Diagnostics Working Group. J Clin Virol 2009; 44:103-5. [DOI: 10.1016/j.jcv.2008.11.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2008] [Accepted: 11/13/2008] [Indexed: 10/21/2022]
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Internally controlled triplex quantitative PCR assay for human polyomaviruses JC and BK. J Clin Microbiol 2008; 46:2829-36. [PMID: 18614652 DOI: 10.1128/jcm.00844-08] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We have developed a triplex TaqMan-based quantitative PCR assay for the human polyomaviruses JC (JCPyV) and BK (BKPyV). The assay simultaneously detects and quantifies both JCPyV and BKPyV in human clinical samples, and it includes an internal amplification control consisting of murine polyomavirus (MuPyV) plasmid DNA. We developed the assay for the Roche LightCycler 480 platform with the reporter dyes VIC, 6-FAM, and Cy5 for MuPyV, BKPyV, and JCPyV, respectively. The assay had a high specificity for BKPyV and JCPyV when either viral genome was present alone or in mixed samples over a range of 10(1) to 10(7) copy numbers per reaction. The analytical sensitivity was 50 copies for BKPyV and 10 copies for JCPyV. The use of the MuPyV internal control ensured monitoring of the quality of the extraction and of PCR inhibition, even in samples such as cerebrospinal fluid and plasma in which controls based on host genes cannot be effectively used. In addition, we developed a similar assay using a different dye configuration (6-FAM, VIC, and NED) that could be used on an ABI 7500 Fast platform. This assay had sensitivities similar to those of the LightCycler 480 configuration for BKPyV and JCPyV when either viral genome was present alone, but the sensitivity of detection of BKPyV was greatly decreased when an excess of JCPyV (>100-fold) was present in the sample. This internally controlled combined assay offers greater convenience and cost-effectiveness compared to separate assays for each virus and can also detect unexpected PyV activations by testing for both viruses in all samples.
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Mori N, Motegi Y, Shimamura Y, Ezaki T, Natsumeda T, Yonekawa T, Ota Y, Notomi T, Nakayama T. Development of a new method for diagnosis of rubella virus infection by reverse transcription-loop-mediated isothermal amplification. J Clin Microbiol 2006; 44:3268-73. [PMID: 16954259 PMCID: PMC1594746 DOI: 10.1128/jcm.00803-06] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We developed a useful method for the detection of rubella virus genome RNA by reverse transcription loop-mediated isothermal amplification (RT-LAMP) and compared the sensitivity of RT-LAMP with that of other virological tests: reverse transcription-PCR (RT-PCR) and virus isolation. The rubella virus genome was amplified by RT-LAMP from clinical isolates obtained between 1987 and 2004 with similar sensitivities to the Takahashi vaccine strain. The detection limit of RT-LAMP was compared with that of RT-PCR using the Takahashi vaccine strain. We detected rubella virus genome material corresponding to 30 PFU/ml in a culture fluid sample by RT-LAMP within 60 min after the extraction of RNA with equal sensitivity to RT-nested PCR. The positive result rates of RT-LAMP, RT-PCR, and virus isolation were also compared using throat swabs obtained from patients who were clinically diagnosed with acute rubella virus infection in 2004 in Tochigi, Japan. Among nine patients with clinical rubella, the positive result rates were three/nine (33.3%) for virus isolation, six/nine (66.7%) for RT-PCR, and seven/nine (77.8%) for RT-LAMP. Consequently, RT-LAMP for rubella virus would be expected to be a reliable rapid diagnostic tool in the clinical setting.
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Affiliation(s)
- Nobuo Mori
- Laboratory of Viral Infection I, Kitasato Institute for Life Science, 5-9-1 Shirokane, Tokyo 108-8641, Japan
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Hope WW, Walsh TJ, Denning DW. Laboratory diagnosis of invasive aspergillosis. THE LANCET. INFECTIOUS DISEASES 2005; 5:609-22. [PMID: 16183515 DOI: 10.1016/s1473-3099(05)70238-3] [Citation(s) in RCA: 348] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Invasive aspergillosis occurs in a wide range of clinical scenarios, is protean in its manifestations, and is still associated with an unacceptably high mortality rate. Early diagnosis is critical to a favourable outcome, but is difficult to achieve with current methods. Deep tissue diagnostic specimens are often difficult to obtain from critically ill patients. Newer antifungal agents exhibit differential mould activity, thus increasing the importance of establishing a specific diagnosis of invasive aspergillosis. For these reasons, a range of alternate diagnostic strategies have been investigated. Most investigative efforts have focused on molecular and serological diagnostic techniques. The detection of metabolites produced by Aspergillus spp and a range of aspergillus-specific antibodies represent additional, but relatively underused, diagnostic avenues. The detection of galactomannan has been incorporated into diagnostic criteria for invasive aspergillosis, reflecting an increased understanding of the performance, utility, and limitations of this technique. Measurement of (1,3)-beta-D glucan in blood may be useful as a preliminary screening tool for invasive aspergillosis, despite the fact that this antigen can be detected in a number of other fungi. There have been extensive efforts directed toward the detection of Aspergillus spp DNA, but a lack of technical standardisation and relatively poor understanding of DNA release and kinetics continues to hamper the broad applicability of this technique. This review considers the application, utility, and limitations of the currently available and investigational diagnostic modalities for invasive aspergillosis.
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Affiliation(s)
- W W Hope
- School of Medicine, University of Manchester and Wythenshawe Hospital, Manchester, UK
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Mancini N, Ossi CM, Perotti M, Clementi M, DiGiulio DB, Schaenman JM, Montoya JG, McClenny NB, Berry GJ, Mirels LF, Rinaldi MG, Fothergill AW. Molecular mycological diagnosis and correct antimycotic treatments. J Clin Microbiol 2005; 43:3584; author reply 3584-5. [PMID: 16000516 PMCID: PMC1169111 DOI: 10.1128/jcm.43.7.3584-3585.2005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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