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Does the UofW WB produce false positives?
Two questions pertaining to HSV 1+ patients testing for HSV 2....
1. Does University of Washington's Western Blot ever produce false positives after one year, and if so what is that percentage?
2. How often do Focus Elisa's show negative results after one year, and WB show positive?
1. Does University of Washington's Western Blot ever produce false positives after one year, and if so what is that percentage?
2. How often do Focus Elisa's show negative results after one year, and WB show positive?
MEDICAL PROFESSIONAL
PCR is definitely better than culture; either one is equally reliable if positive, but a negative PCR is stronger evidence against herpes than a negative cultures is. In any case, with the test results you report, you can go forward with 100% confidence you are not infected with HSV-2. Congratulations! As to other potential causes of your rash, this forum does not speculate about problems other than STDs. Your GP's opinion seems reasonable to me, but that's all I can say. If you go ahead with plans for another opinion, consider seeing a dermatologist. But in the meantime, forget herpes. For sure you don't have it.
That will be all for this thread. Take care.
That will be all for this thread. Take care.
Also, I believe I had a culture, not a PCR... what is the difference? Is PCR that much better?
Woohoo! Congrats on your negative results. Let HSV go.
Your "lesions" are not herpetic. I'm sure Dr. HHH will give you more insight into that; I just wanted to express my congrats!
Your "lesions" are not herpetic. I'm sure Dr. HHH will give you more insight into that; I just wanted to express my congrats!
All results show negative for HSV2. Two swabs and the Western Blot. However my 'lesions' on my inner thigh have spread a bit, and the sebaceous glands on my scrotum are red and swollen. (Some stay fairly reddened, others go back to normal) My GP has suggested contact dermatitis or jock rash. Indeed, the places theses lesions and red glands appear are in places of friction and sweat. However, I find it maddening that this happened during a time while I was awaiting HSV results. I plan to get a second opinion. Can contact dermatitis cause such inflammation? How concerned should I be with HSV2 at this point?
MEDICAL PROFESSIONAL
The odds are far lower than 50:50 that this new lesion was HSV-2. Closer to 1 in 1000, maybe. But it really isn't useful to speculate when the answer -- your WB result -- will be in hand shortly. Please stop asking additional "what if" questions until then. I will be happy to comment once more at that time.
Also the healing of these lesions haven't been traditional, as I 'picked' at the first mark far too much to examine if it turned into a 'open sore' and the second lesion/blister was rubbed deeply with the swab until it opened up. I suppose my odds are 50/50 this could be HSV2. As it was blister like, however it was in a nontraditional body area and only initially a single lesion.
An Update Dr. HHH. I appreciate your time. I am working to resolve my former account with MedHelp. Evidently there was a problem with my last post and we are working to reopen my account. I am still awaiting my WB results. Unfortunately I did notice a single blister like mark on my upper inner thigh, which I had examined by a Hospital Doctor. He said it did not look to him to be HSV. It was a single lesion that may well have been the result of chaffing (as my boxerbriefs were very damp from sweat and restricting. 2-3 days later I noticed a similar mark which I again had checked out, but this time swabbed. I await those results now. Again the doctor did not seem concerned.
My question is, assuming all my results remain negative, what further responsibility do we have to inspect ourselves after exposures to HSV. Obviously HSV can be obscure, and in reality, we all have minor abrasions, blisters, marks, follicititus, etc from time to time, if not relatively often. How does a rational responsible individual judge when he should be concerned after testing? Thank you as always. I will post my results when I receive them.
My question is, assuming all my results remain negative, what further responsibility do we have to inspect ourselves after exposures to HSV. Obviously HSV can be obscure, and in reality, we all have minor abrasions, blisters, marks, follicititus, etc from time to time, if not relatively often. How does a rational responsible individual judge when he should be concerned after testing? Thank you as always. I will post my results when I receive them.
MEDICAL PROFESSIONAL
Usually the delay just means the WB specimen needs closer inspection; it usually doesn't imply the final result will be either positive or negative. See http://www.medhelp.org/posts/STDs/Western-Blot-Fail/show/1357302
Dr. Handsfield, I am still awaiting my results. I understand that 20% of WB take an extra week of testing. Is this indicative or more likely of a positive result when the extra week is required for additional testing? Or is there some other reason that 20% of samples require whatever this additional testing is?
http://depts.washington.edu/rspvirus/herpes.htm
"The test is an overnight assay and preliminary results ready on most sera 3-5 days after receipt in the lab. About 20% of sera require further testing, which requires an additional 5-7 days."
http://depts.washington.edu/rspvirus/herpes.htm
"The test is an overnight assay and preliminary results ready on most sera 3-5 days after receipt in the lab. About 20% of sera require further testing, which requires an additional 5-7 days."
MEDICAL PROFESSIONAL
The result should come with a clear interpretation. You can expect it to be negative. Cross reactivity is definitely not an issue with WB. The very design of the test precludes that possibility (unlike ELISA/IgG testing). That's one of the reasons it's 5X more expensive.
Since the ball is rolling, I suppose I will go ahead and get the results. Should I have some fear of cross-reactivity creating an unreliable WB false positive? Just curious. I will be happy to post my results. Also, will it be up to my Doc to determine the results? Or will a clear negative or positive result be presented to the lab?
MEDICAL PROFESSIONAL
Your doctor was correct; you don't need the WB to know for sure that you didn't catch HSV2. You can expect the WB to be negative if you go ahead with it -- or just cancel it, which is my preference and will save money you don't need to spend. That you aren't infected after 2 years of sex with an HSV-2 infected partner should not be a surprise. In couples in which one partner has HSV-2, and who never use condoms, the average transmission rate is 5% (1 in 20 couples) every year. With consistent condom use, your risk was lower than that.
Cross reaction is a problem only when a test is positive; it has no influence on negative test results. And in any case, what you read is wrong. Over the years there was speculation that cross reactions with chicken pox and other non-HSV herpes infections could explain some false negative HSV test results, but more recent reseach shows that's not the case.
Cross reaction is a problem only when a test is positive; it has no influence on negative test results. And in any case, what you read is wrong. Over the years there was speculation that cross reactions with chicken pox and other non-HSV herpes infections could explain some false negative HSV test results, but more recent reseach shows that's not the case.
Both tests were done a year after my last exposure. I have read studies from this site that combined testing catches more infections. But I have had chicken pox so perhaps with the combination of a negative Elisa, possibility of cross antigens, and no symptoms I am at a greater risk for a false positive than I am for a reliable negative result. Should I cancel my testing?
From advice from another (less reliable) web page; I ordered an ELISA and a WB last week. My Family Doctor said the Elisa would be plenty, and the WB would be overkill and he has seen many WB's (such as those for Lyme Disease) end up Falsely Positive. He ok'ed both tests upon my pressure.
I had a 2 year relationship with an HSV2 female. We knew this prior to the relationship. We had a normal sex life with no protection except the use of condoms for genital sex.
I have not noticed any lesions. My ELISA came back positive for HSV 1 and negative for HSV 2. I will be waiting on my WB results. Can I expect them to be negative?
I had a 2 year relationship with an HSV2 female. We knew this prior to the relationship. We had a normal sex life with no protection except the use of condoms for genital sex.
I have not noticed any lesions. My ELISA came back positive for HSV 1 and negative for HSV 2. I will be waiting on my WB results. Can I expect them to be negative?
MEDICAL PROFESSIONAL
Welcome to the forum.
To be sure we're on the same page with respect to terminology: if someone does not have a particular disease and the test shows positive, that's false positive. If s/he IS infected and the test is negative, that's false negative.
You seem to be asking about false negative results -- i.e. can WB remain negative even though someone has HSV-2? That can happen. However, the ELISA test (IgG) is more sensitive than WB. If ELISA is negative, positive WB is rare. For that reason, WB is not normally used to test people with negative IgG tests for HSV-2. Its primary purpose is to confirm a positive ELISA, especially if that gave borderline results.
So the direct answers to your questions are:
1) As far as known, there is no such thing as a false positive WB for HSV-2. A positive WB always reliably indicates the person has HSV-2.
2) It is rare that ELISA is negative and WB positive. When it happens, the WB would be considered the definitive result.
If you were suspected to have HSV-2 and your ELISA/IgG is negative for HSV-2 at one year, you can be quite certain you were not infected with HSV-2, and normally WB testing would not be recommended. But if it were done and positive, it would mean you have HSV-2 after all.
Because the blood tests are not perfect, other factors often are necessary to decide whether or not someone is infected with HSV-2. If you would like to tell me more of your situation -- exposure history, symptoms, and exact (numerial) blood test results, perhaps we can come to a reasonably accurate judgment as to whether or not you are infected.
Regards-- HHH, MD
To be sure we're on the same page with respect to terminology: if someone does not have a particular disease and the test shows positive, that's false positive. If s/he IS infected and the test is negative, that's false negative.
You seem to be asking about false negative results -- i.e. can WB remain negative even though someone has HSV-2? That can happen. However, the ELISA test (IgG) is more sensitive than WB. If ELISA is negative, positive WB is rare. For that reason, WB is not normally used to test people with negative IgG tests for HSV-2. Its primary purpose is to confirm a positive ELISA, especially if that gave borderline results.
So the direct answers to your questions are:
1) As far as known, there is no such thing as a false positive WB for HSV-2. A positive WB always reliably indicates the person has HSV-2.
2) It is rare that ELISA is negative and WB positive. When it happens, the WB would be considered the definitive result.
If you were suspected to have HSV-2 and your ELISA/IgG is negative for HSV-2 at one year, you can be quite certain you were not infected with HSV-2, and normally WB testing would not be recommended. But if it were done and positive, it would mean you have HSV-2 after all.
Because the blood tests are not perfect, other factors often are necessary to decide whether or not someone is infected with HSV-2. If you would like to tell me more of your situation -- exposure history, symptoms, and exact (numerial) blood test results, perhaps we can come to a reasonably accurate judgment as to whether or not you are infected.
Regards-- HHH, MD
('after one year' meaning after one year after an HSV2 exposure)
You are reading content posted in the STDs Forum
Herpes spreads by oral, vaginal and anal sex.
Herpes sores blister, then burst, scab and heal.
STIs are the most common cause of genital sores.
Millions of people are diagnosed with STDs in the U.S. each year.
STDs can't be transmitted by casual contact, like hugging or touching.
Syphilis is an STD that is transmitted by oral, genital and anal sex.
