Module 4: Polymerase Chain Reaction (PCR)
Module 4.4: Real-Life Example
Clinical Scenario
You are working in a large shelter and there has been a recent outbreak of kennel cough. You decide to run an RT-PCR Respiratory panel to get a better understanding of the potential respiratory pathogens in the shelter and aid in the development of isolation, control, and vaccination protocols. You chose 4 sick dogs to run the RT-PCR respiratory panel on. The following are results from the Pneumovirus RT-PCR data on those 4 sick dogs.
![Dog 1 has a negative result and an undetermined Ct value. Dog 2 has a positive result and a Ct value of 36.0251. Dog 3 has a positive result and a Ct value of 20.1314. Dog 4 has a positive result and a Ct value of 37.0096.](https://pressbooks.umn.edu/app/uploads/sites/104/2021/05/text.png)
Reference interval interpretation
Cycle Threshold (Ct) |
Interpretation |
---|---|
Ct < 29 | Strong positive |
Ct 30-37 | Moderate positivity |
Ct >38 | Weak positive |
Knowledge check
Key Takeaways
- PCR is an amplification technique that allows for the detection of genetic material in very small amounts
- PCR testing is not always the best choice as an infectious disease screening tool
- This test is very sensitive and very specific
- High CT values may be an indicator of a false positive