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Interpreting Western Blot Results
Doctors - first let me thank you for the valuable service you provide in this forum.
A woman I have been seeing and I were recently tested for STD’s including for HSV-2. She had a result of 1.22 value for a standard HSV-2 IgG test. (I was negative.) She was not tested for HSV-1; however, she did have a single episode of a cold sore on her lip years before. As she had never observed symptoms of a genital outbreak, I suggested she consider a Western Blot test for HSV-2. A week later she had a WB result of 8.8 and was told by her Doctor this was a positive result. (Interestingly they said the WB test was run in San Diego as opposed to Washington State.) Her doctor could not explain the value scale of a western blot result and inferred it was the same for the IgG test. I’ve been unable to find out how to interpret the results for a WB and thought to ask if you could help. Also - is there a linear correlation between the two tests? Did her antibody titer spike 7x in a week? Does this indicate a particularly infectious phase?
Moving forward, we plan to continue to use condoms for protection. I realize condoms are not a guarantee to prevent HSV-2 infection. She now has a prescription for Acyclovir. Does taking a dose 24 hours in advance and again the day of sex reduce the viral burden and chances of transmission?
Also, is there a possibility her previous lip lesion was HSV2 instead of HSV1? (I can ask her to run a test on the latter.) If yes, does kissing or oral sex have the same risk of transmission as genital sex? My understanding is there is no way to tell where HSV resides absent clinical symptoms. Finally, just to confirm, the chance of transmission from her genitals to my hand to my genitals is very low?
Thank you again for helping sort through all of this.
Peter
A woman I have been seeing and I were recently tested for STD’s including for HSV-2. She had a result of 1.22 value for a standard HSV-2 IgG test. (I was negative.) She was not tested for HSV-1; however, she did have a single episode of a cold sore on her lip years before. As she had never observed symptoms of a genital outbreak, I suggested she consider a Western Blot test for HSV-2. A week later she had a WB result of 8.8 and was told by her Doctor this was a positive result. (Interestingly they said the WB test was run in San Diego as opposed to Washington State.) Her doctor could not explain the value scale of a western blot result and inferred it was the same for the IgG test. I’ve been unable to find out how to interpret the results for a WB and thought to ask if you could help. Also - is there a linear correlation between the two tests? Did her antibody titer spike 7x in a week? Does this indicate a particularly infectious phase?
Moving forward, we plan to continue to use condoms for protection. I realize condoms are not a guarantee to prevent HSV-2 infection. She now has a prescription for Acyclovir. Does taking a dose 24 hours in advance and again the day of sex reduce the viral burden and chances of transmission?
Also, is there a possibility her previous lip lesion was HSV2 instead of HSV1? (I can ask her to run a test on the latter.) If yes, does kissing or oral sex have the same risk of transmission as genital sex? My understanding is there is no way to tell where HSV resides absent clinical symptoms. Finally, just to confirm, the chance of transmission from her genitals to my hand to my genitals is very low?
Thank you again for helping sort through all of this.
Peter
MEDICAL PROFESSIONAL
Minor clarification: I think Labcorp doesn't use Focus tests -- Focus is a subsidiary of Quest, Labcorp's main competitor. But the principle is the same: all HSV immunoblots basically just replicate other methods to detect IgG antibody. This positive result may increase the likelihood that your partner's low-positive IgG result is true. But the WB is still required to know for sure. I don't want to overly raise your hopes that the WB will be negative for HSV-2. We'll just have to wait and see.
MEDICAL PROFESSIONAL
Aha! Mystery solved.
The HSV immunoblot isn't the Western blot. The Focus immunoblot test is essentially the same as the HerpeSelect ELISA and it is giving the same result, which may be false positive. (Immunoblot and ELISA are different technical mechanisms to detect antibody -- but the two tests mesasure exactly the same HSV antibodies.) So she should go ahead with the plan for an HSV Western blot at the Univeristy of Washington clinical laboratory. Any lab can send a specimen to any referral laboratory; your local Labcorp will know how to do it. Let me know the result, which you should have a week or so after sending the specimen.
The HSV immunoblot isn't the Western blot. The Focus immunoblot test is essentially the same as the HerpeSelect ELISA and it is giving the same result, which may be false positive. (Immunoblot and ELISA are different technical mechanisms to detect antibody -- but the two tests mesasure exactly the same HSV antibodies.) So she should go ahead with the plan for an HSV Western blot at the Univeristy of Washington clinical laboratory. Any lab can send a specimen to any referral laboratory; your local Labcorp will know how to do it. Let me know the result, which you should have a week or so after sending the specimen.
Here is the most updated information:
She was at the clinic when she received her recent results and asked to confirm the test was for a Western Blot. The staff looked up the paperwork and replied “yes – it was the immunoblot test”. They also said it was run at a lab in San Diego. At my suggestion, she asked her Doctor how the scale used for the first test could be compared to the results of the second, and he replied “I don’t know”.
I have the print out of her latest test result but it does not provide much information about the nature of the test. It was done by LabCorp. There is a patient and doctor ID # but no code for the exact test run. Under “Tests” it states “HSV Type 2-Specific Ab, IgG” Underneath this field it says “HSV 2 IgG, Type Specific” followed by “Result 8.8” and Flag “High”. The scale used for the Reference Interval are the same for the previous test.
Researching test offered LabCorp, I found a reference for an “immunoblot” HSV serology test #138487. The test is described as “Qualitative, individual detection of IgG antibodies specific to HSV-1 and/or HSV-2 infection, confirm or rule possible infection…” The rest of it reads the same as the standard, non “qualitative” HSV test #164905. There is no mention of using a gel to separate antigens by molecular weight. Possibly they are using different antigens in different wells for an Elisa type immunoflourescent reading and that this accomplishes the same thing as a true Western Blot?
Does the reading from this new test, change your view on her diagnosis? Assuming Labcorp has properly normalized both tests to use the same Reference Interval scale, does the spike in her last results imply more recent exposure? Does a higher antibody titer correlate with higher amount of viral shedding/infectiousness?
If there is any ambiguity remaining after these two tests, we would like to have a Western Blot run at University of Washington. Can you advise how this can be done? If her current clinic has a contract with LabCorp, will Labcorp send samples to UW? Will Quest send samples or just use their own test? If we have to sidestep a physician ordering the test and pay out of pocket, we would consider that alternative if it is the most practical method.
Thank you in advance for your feedback.
She was at the clinic when she received her recent results and asked to confirm the test was for a Western Blot. The staff looked up the paperwork and replied “yes – it was the immunoblot test”. They also said it was run at a lab in San Diego. At my suggestion, she asked her Doctor how the scale used for the first test could be compared to the results of the second, and he replied “I don’t know”.
I have the print out of her latest test result but it does not provide much information about the nature of the test. It was done by LabCorp. There is a patient and doctor ID # but no code for the exact test run. Under “Tests” it states “HSV Type 2-Specific Ab, IgG” Underneath this field it says “HSV 2 IgG, Type Specific” followed by “Result 8.8” and Flag “High”. The scale used for the Reference Interval are the same for the previous test.
Researching test offered LabCorp, I found a reference for an “immunoblot” HSV serology test #138487. The test is described as “Qualitative, individual detection of IgG antibodies specific to HSV-1 and/or HSV-2 infection, confirm or rule possible infection…” The rest of it reads the same as the standard, non “qualitative” HSV test #164905. There is no mention of using a gel to separate antigens by molecular weight. Possibly they are using different antigens in different wells for an Elisa type immunoflourescent reading and that this accomplishes the same thing as a true Western Blot?
Does the reading from this new test, change your view on her diagnosis? Assuming Labcorp has properly normalized both tests to use the same Reference Interval scale, does the spike in her last results imply more recent exposure? Does a higher antibody titer correlate with higher amount of viral shedding/infectiousness?
If there is any ambiguity remaining after these two tests, we would like to have a Western Blot run at University of Washington. Can you advise how this can be done? If her current clinic has a contract with LabCorp, will Labcorp send samples to UW? Will Quest send samples or just use their own test? If we have to sidestep a physician ordering the test and pay out of pocket, we would consider that alternative if it is the most practical method.
Thank you in advance for your feedback.
MEDICAL PROFESSIONAL
Dr. Hook has informed me that the Focus company -- the producer of the HerpeSelect and now a subsidiary of Quest Laboratories -- has its own HSV Western that produces a numerical result. Dr. Hook and his colleauges have studied and found it to be unreliable. I would suggest you advise your partner to have a repeat WB, with a specific request to send the specimen to the Univeristy of Washington clinical lab. I'm betting it will turn out she doesn't have HSV-2.
MEDICAL PROFESSIONAL
Welcome back to the forum.
Your partner's low HSV-2 index value (1.22) suggested she doesn't have HSV-2. As normally performed, the HSV Western blot test normally i read visually (or by a scanning machine) to analyze black and white bands that correspond to various antigens in the virus. Maybe some lab has devised a way to convert the results to numerical values, but I have no idea how to interpret a numerical result of 8.8 or any other number. I have to wonder whether there was a miscommunication and maybe this isn't a WB result at all. The best I can suggest is to ask her doctor to provide more details; the report may include more information, e.g. about cut-off values. Or learn the lab name and ask them directly.
So given her low ELISA ratio of only 1.22, I still think there's a good chance your partner doesn't have HSV-2. But since it's not possible to be certain (at least not yet), common sense prevention measures are reasonable until it's sorted out. The average transmission risk from asymptomatic, longstanding HSV-2 infections is around 5% each year, in couples having unprotected vaginal sex 2-3 times a week. Anti-HSV suppressive therapy with valacyclovir reduces that by 50%, and consistent condom use by another 50%. So the odds are strong that you would remain infection free, even if this realtionship continues for several years.
Acyclovir hasn't been as well studied as valacyclovir and the dose required to reduce transmission risk hasn't been studied at all. But whichever drug your partner takes, it should not be as you describe. She should take it on a consistent daily (valacyclovir) or twice daily (acyclovir) basis. I imagine the peculiar regimen you suggest would have some prevention benefit, but I could not venture a guess as to how good it would be.
Oral HSV-2 is uncommon, and is very rare in people without genital HSV-2. So is it "possible" she has oral HSV-2? Yes, but very unlikely. In any case, it's hard to be certain she has oral herpes at all, based on only a single outbreak several years ago. Anyone who has oral HSV of either type could transmit it to a partner by kissing or oral sex. However, the transmission risk for any single exposure, in the absence of a visible outbreak, would be very low.
Indirect contact like you describe (genital-hand-genital) rarely if ever transmits HSV or other STDs.
If you can get more information about your partner's supposed WB result, let me know.
Best wishes-- HHH, MD
Your partner's low HSV-2 index value (1.22) suggested she doesn't have HSV-2. As normally performed, the HSV Western blot test normally i read visually (or by a scanning machine) to analyze black and white bands that correspond to various antigens in the virus. Maybe some lab has devised a way to convert the results to numerical values, but I have no idea how to interpret a numerical result of 8.8 or any other number. I have to wonder whether there was a miscommunication and maybe this isn't a WB result at all. The best I can suggest is to ask her doctor to provide more details; the report may include more information, e.g. about cut-off values. Or learn the lab name and ask them directly.
So given her low ELISA ratio of only 1.22, I still think there's a good chance your partner doesn't have HSV-2. But since it's not possible to be certain (at least not yet), common sense prevention measures are reasonable until it's sorted out. The average transmission risk from asymptomatic, longstanding HSV-2 infections is around 5% each year, in couples having unprotected vaginal sex 2-3 times a week. Anti-HSV suppressive therapy with valacyclovir reduces that by 50%, and consistent condom use by another 50%. So the odds are strong that you would remain infection free, even if this realtionship continues for several years.
Acyclovir hasn't been as well studied as valacyclovir and the dose required to reduce transmission risk hasn't been studied at all. But whichever drug your partner takes, it should not be as you describe. She should take it on a consistent daily (valacyclovir) or twice daily (acyclovir) basis. I imagine the peculiar regimen you suggest would have some prevention benefit, but I could not venture a guess as to how good it would be.
Oral HSV-2 is uncommon, and is very rare in people without genital HSV-2. So is it "possible" she has oral HSV-2? Yes, but very unlikely. In any case, it's hard to be certain she has oral herpes at all, based on only a single outbreak several years ago. Anyone who has oral HSV of either type could transmit it to a partner by kissing or oral sex. However, the transmission risk for any single exposure, in the absence of a visible outbreak, would be very low.
Indirect contact like you describe (genital-hand-genital) rarely if ever transmits HSV or other STDs.
If you can get more information about your partner's supposed WB result, let me know.
Best wishes-- HHH, MD
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.
