# Testing for infectious diseases



## bucksfizz (Oct 31, 2010)

Hello,

I don't know if you will be able to help me here. 

I would have posted this in the embryologist section, only I don't think anyone replies there anymore.

I was wondering if you had any knowledge of PCR (Polymerase Chain Reaction) tests? 

I asked my clinic to quarantine my donor embryos for 180 days and then rescreen donors for infectious disease antibodies. They told me the antibody test is 'old fashioned' and they now use this PCR test which is, apparently,  100% reliable. Would you happen to know anything about this? Thanks in advance for any help.


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## Mistletoe (Holly) (Jan 1, 2007)

I am not an expert or virologist, but I do work in a leading teaching hospital intensive care unit and I know that when we have someone in with suspected viral infection e.g. viral meningitis or Swine flu, we do viral PCRs. This looks for the DNA of the virus, so would detect if the virus was present.
We would be waiting forever for the virus to grow in the lab or waiting for the patient to produce antibodies. We need an instant answer there and then if we are going to give the right antiviral drug to save a patient's life, or isolate them for infection control purposes.

It is true that if the virologist is looking for the actual DNA of the virus this would give a quicker answer than waiting 6 months for the patient to produce antibiodies to the said virus. You would know on a particular day if the patient were infected with a virus or not.

I suggest that you ask a virologist for a proper answer, but this how I understand it.


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## bucksfizz (Oct 31, 2010)

Hello,

Thank you very much for your answer. I don't know if you can help with 2 follow-up questions? 

From what you're saying, it seems this test is reliable, but is there any chance of a false negative? 

And, is there any 'window period' for this test? I read on the internet that if an infection, eg. HIV,  was very recent (under 5 days) it would not be picked up. I mentioned this to my doc who said this was incorrect and the test was 100% certain. From what you're saying I get that impression too.

Any views on this please? Thanks again for any advice.


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## Mistletoe (Holly) (Jan 1, 2007)

Like I said I am no expert and this is a question for a virologist.

To be detected by the test the virus would have to be in the sample.
I am totally guessing here, but if the virus is in such low amounts to be able to escape being in a sample, then would the person really be infectious?

If you are that concerned then you need to contact an expert virologist.
Your doctor could do this for you I am sure.


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