Culture Positive but Serology Negative

Ronan

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I got a positive result from my Culture Test a couple of weeks ago but just got my Antibody Serology test back and it was negative. Does anyone know what this means?

Could i have got a false positive from the culture?

If the Culture test was right maybe the Serology test isint 100% accurate so it just missed it on the day?

What exactly is the Serology Antibody testing for? Is the Culture and active infection and Serology tells you if you have ever had it. I dont see though how i can have an active infection but no antibodies. Unless i have got this bit wrong?

Thanks
 

maryb

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Thats how I thought it worked too Ronan - have you contacted VIPDx, I'm sure they will explain it for you.
 
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Many people who are more severely affected in particular will have negative serology tests because their immune systems are not doing great, and they have stopped producing antibodies.

Even where anti-bodies ARE produced, production is likely weak, and may not be picked up every time.

At this point in time, the culture test should be considered more reliable than the serology test, especially for individuals who are severely affected.
 

Ronan

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Hmmm, i'd only describe myself as moderately ill. I work a few hours most days and have never been bed bound. I thought the Serology test was the "new and improved" xmrv test which is why i waited for it to come out before getting tested. I got the 2 tests done at the same time, really just getting the Culture to double confirm if my Serology came back Positive. The irony now of having it come out the other way around. I'd say the Culture results are correct but its just making me very nervous now of a false positive :eek:(
 

Alexia

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Hi Ronan,
I'm also confused with your results. I thought culture positive and serology negative would not be possible! How confusing for you!
 

ukxmrv

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Ronan, how long have you been ill for? Was it acute onset or gradual and is any sign of the disease in your family? Just wondering if any of these factors could be relevant.

Everything is so new and I'm wondering if we will get different results based on all these different things. Will we get results on one test from (for example) people infected as children or from their parents?
 

Ronan

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MarxyGrouch looks like you are on the ball with this. I did the test myself through VipDx but am a patient of De Meierleir. I just emailed him today with the conflicting results and he responded with the following:

"Chronic patients often have negative serology and positive culture/PCR. The virus attacks the B cells which produce antibodies..."

I'm still nervous about a false positive but really the Culture test along with my bad health for over 8 years with most of the classic ME symptoms makes me believe the Culture is the correct result. Just so much riding on this any doubt leads to alot of worry!

ukxmrv: I have been unwell for over 8 years with gradual onset. I tested positive for De Meirleir's urine test last year. My mother has ME as well. I think it started for he when pregnant with me or just after. She was very poorly with it for about 8 years but then got substantially better. Still has some problems from it but is living a failry normal life living within some limitations.

Also, im slightly confused about the format of my results.

- For the XMRV Viral Culture DNA detection, qual. Under "Normal" it is blank, under "Abnormal" it says "Positive", and then under "Normal Range" it says "None Detected"

- Then for XMRV Serum Antibody detection. Under "Normal" it says "None Detected", under "Abnormal" it is blank, and then under "Normal Range" it is blank

Should the Culture provide a normal range at all? I dont think it should which would explain why it says "None Detected" or am i missing something here?
 

Alexia

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Ronan,

It's good that De Meileir replied to you quickly. This situation must be really unsettling for you. I thought that false positives didn't exist so probably you are positive. The only thing you can do is to repeat the culture test when you have the financial resources.
Do you understand what De Meileir means with "Chronic patients often have negative serology and positive culture/PCR. The virus attacks the B cells which produce antibodies..." almost all of us are chronic patients I would say..
 

Ronan

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Ronan,
Do you understand what De Meileir means with "Chronic patients often have negative serology and positive culture/PCR. The virus attacks the B cells which produce antibodies..." almost all of us are chronic patients I would say..
I was a bit confused by this line as well. "Chronic" is open to interpretation. Do people on here think he means patients who have very bad ME or patients who have had ME for a long time?
 
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Ronan, I'm sorry this has been confusing right at a time you were hoping for clarification! My understanding is the same as MarxyGrouch's- if the immune system is crummy, you may not be making the antibodies. The antibody test has a 50% false negative rate. However, since blood is probably not the repository for the retrovirus, the culture test can also come out negative- about 20% of the time. Together, the tests have a false negative rate of only 10%. So, if either the culture/PCR or serology was positive, you've got it! Except for the "contamination" naysayers, I haven't heard anyone talking about false positives. Also, the tests at this point are quantitative- they only give a positive or negative result, so you weren't missing anything!
 

Ronan

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Ronan, I'm sorry this has been confusing right at a time you were hoping for clarification! My understanding is the same as MarxyGrouch's- if the immune system is crummy, you may not be making the antibodies. The antibody test has a 50% false negative rate. However, since blood is probably not the repository for the retrovirus, the culture test can also come out negative- about 20% of the time. Together, the tests have a false negative rate of only 10%. So, if either the culture/PCR or serology was positive, you've got it! Except for the "contamination" naysayers, I haven't heard anyone talking about false positives. Also, the tests at this point are quantitative- they only give a positive or negative result, so you weren't missing anything!
Thanks! Thats put my mind at rest a bit. The ups and downs of ME never end!!!!

Are you sure about the 50% false negatives for the Serology though, that seems very high. I thought the serology was an improved test on the Culture?
 
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Ronan, it is my understanding that the serology picks up some positives that the culture did not. The two tests together are very accurate, but alone they will miss some cases. The 50% quote was from a CFS doctor who's been involved in research. Actually, I misquoted the false negative for culture- it was 25%, not 20%.
 
C

Cloud

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Ronan, it is my understanding that the serology picks up some positives that the culture did not. The two tests together are very accurate, but alone they will miss some cases. The 50% quote was from a CFS doctor who's been involved in research. Actually, I misquoted the false negative for culture- it was 25%, not 20%.
That has been my understanding as well. Also, it has been my understanding that the Serology results are significant for treatment planning. I would think that a person Culture+, Serology- would have a treatment plan designed to elicit an antibody response....but that is just speculation on my part. I just know that my doc intends to use the Serology results together with the old culture results to make a Tx plan.

3CFIDS...was this CFS doctor referring to VIP Serology on the 50% false negatives? I must be misunderstanding you because no antibody tests have that high a percentage of false negatives....they would be useless.
 

Ronan

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I gave VipDx a ring. The woman i spoke to assured me that if either one is positive you are infected with the virus. I asked about the possibility of false positives and she said that all results are double checked by the WPI for quality control purposes so if you tested positive its a definite result. Im going to see De Meirleir in a couple of weeks so i'll post up my experiences
 

Alexia

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It's great you got an answer from the VipDx, at least you are a bit reassured that a false negative is not really possible.
Let us know how it goes with your appointment with De Meirleir, we are all learning from each others experiences. What would we do without internet?
Good luck with your appointment Ronan.
 
C

Cloud

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True that you shouldn't get a false reading from those tests. But a negative Ab test doesn't necessarily mean a person is negative for the infection. It just says that your immune system hasn't responded to that particular pathogen for whatever reason. Many pathogens are shape shifting masters of evading an immune response (stealth). So unless there is more to the VIP Serology than just looking for Antibodies, a negative result would not be definitive for ruling out infection. A positive result is another story.
 

jimbob

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cloud, you must be a true blood fan like me. I wish I could shape shift out of my deseased body and into a healthy Jack Russell. LOL Anybody know how long a wait on serology results, they got mine oct 7th.
 
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Cloud

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cloud, you must be a true blood fan like me. I wish I could shape shift out of my deseased body and into a healthy Jack Russell. LOL Anybody know how long a wait on serology results, they got mine oct 7th.
Hey Jimbob.....good to see you, been a while. Yea, shape shifting would be cool.