1887

Abstract

The implementation of widespread unselected screening for in England, using nucleic acid amplification tests (NAATs), has raised concerns regarding the potential increase in misdiagnoses. To increase the positive predictive value, confirmatory testing of positive specimens has been recommended; however, in practice this can be difficult to perform. This study examined the role of two different testing strategies for confirming the status of specimens that had been examined by the ProbeTec Strand Displacement Amplification (SDA) assay (Becton Dickinson). A total of 227 residual clinical specimens in SDA assay collection tubes were sent for confirmatory testing using two different testing approaches: (i) examination using two in-house real-time PCR assays ( and pseudogene) and (ii) examination using the APTIMA Combo 2 (AC2) assay and the APTIMA Monospecific (AGC) tests (Gen-Probe). Of the 113 SDA-positive specimens (including low positives) examined, 93 % were confirmed as -positive using either one or both real-time PCR assays. In contrast, only 34 % were confirmed using the AC2 and/or the AGC assays. All 114 SDA-negative specimens were confirmed as negative using all four confirmatory tests. Clearly the AC2 and AGC assays cannot reliably be used to confirm residual specimens in SDA assay transportation buffers, due to the incompatibility of different platform chemistries. Although high rates of confirmation (93 %) can be achieved when examining residual SDA assay specimens using independent real-time PCR assays, establishing well-validated in-house real-time PCR assays for diagnostic use is a large undertaking for many primary laboratories and so such tests may be better confined to specialist laboratory services.

Loading

Article metrics loading...

/content/journal/jmm/10.1099/jmm.0.028563-0
2011-07-01
2024-03-29
Loading full text...

Full text loading...

/deliver/fulltext/jmm/60/7/909.html?itemId=/content/journal/jmm/10.1099/jmm.0.028563-0&mimeType=html&fmt=ahah

References

  1. Benzie A., Alexander S., Gill N., Greene L., Thomas S., Ison C. 2010; Gonococcal NAATs: what is the current state of play in England and Wales?. Int J STD AIDS 21:246–248 [View Article][PubMed]
    [Google Scholar]
  2. Chen C. Y., Chi K. H., Alexander S., Martin I. M., Liu H., Ison C. A., Ballard R. C. 2007; The molecular diagnosis of lymphogranuloma venereum: evaluation of a real-time multiplex polymerase chain reaction test using rectal and urethral specimens. Sex Transm Dis 34:451–455[PubMed] [CrossRef]
    [Google Scholar]
  3. Dave J., Eastaway A. 2007 Guidance on the Introduction of Molecular Testing for Neisseria gonorrhoeae in Diagnostic Laboratories Health Protection Scotland; Available at http://www.documents.hps.scot.nhs.uk/labs/sbstirl/naats-2007-08.pdf
    [Google Scholar]
  4. Hardwick R., Gopal Rao G., Mallinson H. 2009; Confirmation of BD ProbeTec Neisseria gonorrhoeae reactive samples by Gen-Probe APTIMA assays and culture. Sex Transm Infect 85:24–26 [View Article][PubMed]
    [Google Scholar]
  5. Health Protection Agency 2010 Guidance for Gonorrhoea Testing in England and Wales http://www.bashh.org/news/478_2010-hpa-guidance-on-gonorrhoea-testing
    [Google Scholar]
  6. Ison C. 2006; GC NAATs: is the time right?. Sex Transm Infect 82:515 [View Article][PubMed]
    [Google Scholar]
  7. Moncada J., Donegan E., Schachter J. 2008; Evaluation of CDC-recommended approaches for confirmatory testing of positive Neisseria gonorrhoeae nucleic acid amplification test results. J Clin Microbiol 46:1614–1619 [View Article][PubMed]
    [Google Scholar]
  8. Ota K. V., Tamari I. E., Smieja M., Jamieson F., Jones K. E., Towns L., Juzkiw J., Richardson S. E. 2009; Detection of Neisseria gonorrhoeae and Chlamydia trachomatis in pharyngeal and rectal specimens using the BD Probetec ET system, the Gen-Probe Aptima Combo 2 assay and culture. Sex Transm Infect 85:182–186 [View Article][PubMed]
    [Google Scholar]
  9. Palmer H. M., Mallinson H., Wood R. L., Herring A. J. 2003; Evaluation of the specificities of five DNA amplification methods for the detection of Neisseria gonorrhoeae . J Clin Microbiol 41:835–837 [View Article][PubMed]
    [Google Scholar]
  10. Tabrizi S. N., Chen S., Tapsall J., Garland S. M. 2005; Evaluation of opa-based real-time PCR for detection of Neisseria gonorrhoeae . Sex Transm Dis 32:199–202 [View Article][PubMed]
    [Google Scholar]
  11. Whiley D. M., Sloots T. P. 2005; Comparison of three in-house multiplex PCR assays for the detection of Neisseria gonorrhoeae and Chlamydia trachomatis using real-time and conventional detection methodologies. Pathology 37:364–370 [View Article][PubMed]
    [Google Scholar]
  12. Whiley D. M., Tapsall J. W., Sloots T. P. 2006; Nucleic acid amplification testing for Neisseria gonorrhoeae: an ongoing challenge. J Mol Diagn 8:3–15 [View Article][PubMed]
    [Google Scholar]
http://instance.metastore.ingenta.com/content/journal/jmm/10.1099/jmm.0.028563-0
Loading
/content/journal/jmm/10.1099/jmm.0.028563-0
Loading

Data & Media loading...

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error