Follow-up on diagnostic proficiency of laboratories equipped to perform orthopoxvirus detection and quantification by PCR: the second international external quality assurance study.

Abstract

Two years after the first external quality assurance study on bioterrorism-relevant viruses, we have conducted a follow-up study on orthopoxvirus detection by PCR. Thirty-three laboratories (27 European, 4 Austral-Asian, and 2 American) participated. Samples contained 0 to 40,000,000 DNA copies of lyophilized monkeypox, cowpox, and vaccinia virus per ml. Laboratories achieved a >80% detection chance above 56,234 copies per ml. Global sensitivity was not significantly improved over that of the first study. Twenty-seven and 9 participants, respectively, were able to genotype and quantify virus. Four of 27 genotyping results were incorrect. Quantification accuracy was significantly better for vaccinia virus than for the other viruses. False-positive results occurred in 22 (11.8%) of all 186 tests on negative samples, but 18 of these were contributed by only five laboratories. Fifty-five percent of laboratories could appropriately detect PCR inhibition. The use of either real-time PCR or commercial diagnostic kits had significant positive influence on laboratory performance.

• Authors: Matthias Niedrig, Hermann Meyer, Marcus Panning, Christian Drosten
• Journal: Journal of clinical microbiology (J Clin Microbiol) Vol. 44 Issue 4 Pg. 1283-7 (Apr 2006) ISSN: 0095-1137 [Print] United States
• PMID: 16597852 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• DNA, Viral
• Reagent Kits, Diagnostic

Topics

• Clinical Laboratory Techniques
• DNA, Viral (blood)
• Follow-Up Studies
• Humans
• International Cooperation
• Laboratories (standards)
• Orthopoxvirus (genetics, isolation & purification)
• Polymerase Chain Reaction (methods)
• Poxviridae Infections (virology)
• Quality Control
• Reagent Kits, Diagnostic (standards)