Reliability of negative results for HSV1/HSV2

[spacesndr]

I have some concern about my possible HSV1/2 status. I'm leaving the details of symptoms out because I'm primarily concerned in understanding the accuracy of IgG antibody testing, I hope that's OK.

The test in my area is the combined HSV1/HSV2 test, and I believe it also tests for Herpes Zoster as well. At four weeks this test returned a negative result for both HSV1 and HSV2, and came up negative again at 10 weeks. The results provided do not show any numerical values, simply a statement of "negative for HSV1/2" that is returned to my doctor's office. I plan on testing one last time at 16+ weeks to be absolutely certain.

I read a comment from one of the doctors here that HSV1 IgG results report false negatives 15-20% of the time. This seems surprisingly high... My questions are as follows:

1) Does the type of test I'm taking (combined) provide more or less accurate NEGATIVE results? My understanding is that it's more sensitive than type-specific testing and usually produces false positives, so I'd think it's less likely to produce less false-negatives. Is this correct?

2) Does multiple testing with this same method (4, 10, 16+ weeks) lend more credence to a negative result? Or is that irrelevant since it's the same methodology?

3) Based on other posts I've read, I understand your opinion (between both doctors) that HSV-1 isn't as big a deal and I probably shouldn't worry about it, but it's important to me that I know my HSV-1 status. Is the comment regarding 15-20% false negatives correct? If so, does it apply to this testing method as well?

4) Would taking a test of another type (whichever is offered by Planned Parenthood, for example) be worthwhile in ensuring accuracy of a negative result?

Thank you for your time.

[Edward W Hook, MD]

The escription of the test you describe is not familiar to me. there are a number of type specific tests.  You should ask your doctor.  Without knowing about the test, I cannot comment on the reliablity of the result.  EWH

[spacesndr]

Hi Dr. Hook,

Thank you for your reply. I apologize for the broad nature of the question, but I've seen many comments about the accuracy of testing here before so I was hoping a could get a bit more information (it's tough to find online elsewhere).

I live in Canada and this is the only test that is offered. Type-specific testing can be done but only in special-cases, and the odds of my doctor agreeing to it are minimal. In order to get a type-specific test I'll likely have to make a trip to the US. So I'm trying to work with what's available to me at the moment if possible.

The test that I've taken is described as "Serology EIA: HSV IgG". Is this a protein-based test like you describe?

Basically I understand and accept that this test might return a false-positive result. If a positive result is returned I'll take whatever steps I can to confirm it and determine which type (including travelling to the US).

But what I really would like to know is can this test be trusted for a negative result? Or is it horribly inaccurate in that regard as well?

[Edward W Hook, MD]

Your question starts by putting us at a disadvantage.  Our suggestions an recommendations are based on the context of our client’s questions, not abstractions.  For abstract statements you should go to the manufacturers of the test.  

There are no perfect tests.  All tests have variable performance in terms of time to positivity, sensitivity, specificity, positive and negative predictive value.  These in turn are a function of when and how the test is used and how likely the infection is to be present.

There are no combined tests for HSV-1 and HSV-2 that we recommend because a large body of scientific study shows that such test have a major problem with false positives and a proven inability to distinguish HSV-1 from HSV-2.  Further, the current "state of the art" is the typically isolated testing in the absence of indications and questions to be addressed by testing is a bad idea as false positives become relatively common in such situation.

If you feel you must test for HSV antibodies, please test for  HSV using a gG protein-based, type specific test. there are many available.  It sounds as though that is not what you have been tested with however.  EWH