Question

[medhelp1999]

I had a possible HSV1 exposure 8 weeks ago.  2 weeks after incident my IGG was .29 with a reference range of 0.00-.89.  6 weeks after my IGG was .55 with a reference range of 0.00-.89.  My lips have been irritated this entire time.  Twice took a day to 2 days worth of Valtrex because I felt swelling in one area (not within 48 of the blood tests though).  Can you help explain this jump in the IGG?  Is it possible I have HSV1 even though the blood came back ok?  When should I repeat the test?

[Edward W Hook, MD]

Prolonged valacyclovir might modify test results but not a few days.

Your second question relates to biochemistry.  There is no such thing as a zero result in most biological assays.  If the results were being reported out as positve or negative your results will be reported as negative.  EWH

[medhelp1999]

Thank you for your help.  Would the Valtrex throw off the blood test results?    If I don’t have the virus, why would I have any detection of the virus, even if it’s within the reference range?

[Edward W Hook, MD]

Welcome to the Forum.  Please know that most exposures to partners with HSV do not lead to infection.  In fact, fewer than 1% of exposed persons become infected so the odds are very much in your favor.  At 25 days following the appearance of lesions (the only appropriate baseline for studies), about half of persons with newly acquired HSV-1 will have positive tests and at 6 weeks over 2/3's will have positive tests.  At 4 months, the test is considered reliable with complete results.

Negative tests are negative and the values within the negative range tend to "bounce around" within the negative range.  This variation is meaningless and does not suggest that you are acquiring infection.  The variation can be due to day to day variation in the test, the conditions in which the test is performed (temperature for instance) or variation in your own levels of antibodies to other things due to your state of hydration, other illnesses,  etc.  Negative is negative and the test variation should not concern you.  

I would advise you not to take valacyclovir and see what happens.  Taking valacyclovir will not change whether or not you have the infection but it will confuse things if you do.

Hope this helps.  EWH