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Laboratory Diagnostics, Specimen Collection, and Biosafety Issues. Learning Objectives. Describe avian influenza-related laboratory procedures Define laboratory safety List elements of specimen collection kit Explain how to collect & transport specimens Describe infectious waste disposal
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Primary method: detection of H5N1 viral RNA by reverse-transcription polymerase chain reaction (RT-PCR)
Taken from: World Bank Training by Alexander Klimov, CDC
RAPID TESTS NOT RECOMMENDED
For Detection of human H5N1 virus infection
Delay for anti-H5
levels to rise
Requires acute and convalescent sera, 3 weeks apart
Not useful for clinical
Can confirm epidemic cases, if respiratory specimens not available
Require acute and convalescent sera
(serum obtained >21 days from onset)
* four-fold or greater increase between acute and convalescent sera
Which of the following is the best technique to test respiratory samples for avian influenza?
Answers: a. PCR-based techniques
Which of the following situations is most likely to lead to the misinterpretation of diagnostic tests?
Answer: d. Instead, you should use multiple tests to confirm results.
Dr. Terrence Tumpey examines reconstructed 1918 Pandemic Influenza Virus inside a specimen vial in a Biosafety Level 3-enhanced laboratory setting. Courtesy CDC/James Gathany.
Increasing biosafety levels = increasing levels of personnel & environmental protection
If laboratory does not meet BSL2 requirements, ship appropriately packaged specimen to reference laboratory
What Biosafety Level needs to be in place in order to culture H5N1?
Answer: d. BSL-3enhanced safety measures and guidelines should be used for culturing potential H5N1 viruses
Store kit in a dry, cool place
Keep kit accessible for after hours
at 4 - 8 ºC
Use throat swabs for avian influenza and
nasopharyngeal swabs for seasonal influenza
Prepare to collect specimens before you leave for the field
From an Ambulatory patient
From an Intubated patient
As soon as possible, ideally within 7-10 days after symptom onset
2-3 weeks after the acute sample (> 21 days after symptom onset)
Use pre-printed barcode labels:
Label each specimen with:
True or False: Are nasopharyngeal swabs best for seasonal or avian influenza?
For specimens in VTM:
Goal: protect specimens during transportation
Which of the following is true about storing clinical specimens (sera or specimens in VTM)?
Answer: a. Both sera and specimens in VTM can be stored for certain periods at 4°C for up to a week. Neither of these samples should be stored in a standard freezer, because the freeze-thaw cycle will destroy the virus
Contaminated work surface:
Exposed laboratory worker:
Maintain a database to track:
A portion of a total amount of a solution
A machine that uses high-speed rotation to separate materials with different densities.
Growing of microorganisms in a nutrient-rich medium.
Component genetic material such as DNA or RNA found in all cells in humans, animals, bacteria, and viruses. Every species and organism has a unique pattern.
A glass or plastic tube used to measure or transfer small amounts of liquid.
A liquid solution made of salt and water.
Viral Transport Medium (VTM)
The preservative liquid in which specimens are stored until they are tested.