Swab test vs. blood test?

[icetrails]

For context, I am a transgender man. I started having a genital rash over a month ago, and when I first went to the doctor, they thought it didn't look like herpes. They swabbed the rash and it came back positive for HSV-1. 

Even after taking a course of acyclovir, I was still having a lot of irritation for several weeks. I followed up with a dermatologist, who said that the bumps I was noticing were normal, and that it was more likely a yeast infection. She sent me home with an anti-fungal cream, which did seem to help.

My symptoms went away, so my partner and I had sex for the first time in several weeks. The day after, I was itchy and irritated again. 

I went to a naturopathic doctor who was recommended to me (I have other health concerns I was needing advice with) and she confirmed that I had a yeast infection, not an HSV outbreak. She recommended that at some point, I do a blood test for herpes to confirm my result.

I did some reading online, and it sounds like the swab test is more likely to give an accurate positive result than the blood test. So I'm wondering, what's the point in getting a blood test done? If my swab test was positive, is there any reason to suspect I might have had a yeast infection, and not an HSV outbreak, all along? 

I recognize that part of me was excited about the suggestion that I might not actually have herpes, more so for navigating sexual encounters than anything else. Clearly, there is a lot of stigma surrounding herpes. But I've also gotten to a place of feeling pretty comfortable with my status, and don't want to "undo" that by getting my hopes up that the positive test might have been wrong. 

[Flowerteacher55]

Hi!! 

I hope you are doing well. 

It is wonderful that you talked to doctors about everything. You present a really interesting question! 

For starters, swab tests work by taking a viral sample of DNA and testing it to see if it is HSV. Swab tests are prone to human error, since if the medical professional preforming the swab doesn't swab enough DNA, it can produce false negatives. 

The IgG and IgM blood tests work by detecting antibodies, so not the viral DNA itself like the swab test, but instead the antibodies your body builds up in response to HSV. Blood tests can of course be inaccurate as well, depending on timing and how quickly your body build up antibodies. 

It is possible to have both an HSV outbreak (in this case a primary outbreak) AND a yeast infection at the same time. Your swab came back positive, and it is possible that you have HSV and sadly also had a yeast infection, which would make sense because intercourse can cause a flare-up of yeast infection issues, as you described, since new bacteria is entering the body/moving around from your partner to you.

If you would like, totally get a blood test for extra knowledge. Knowledge is power! For your own peace of mind and for own physical health peace of mind, it might be a good idea. 

Also, to clarify, when you had the first outbreak, you had sores, correct? The antivirals didn't help so you took the Prednisone and it helped. It would make sense if you had an outbreak and a yeast infection simultaneously. 

I hope this helps!! 

Sending good vibes and blessings of health and happiness your way ☀️

[icetrails]

On 2/21/2022 at 9:45 AM, Flowerteacher55 said:

Hi!! 

I hope you are doing well. 

It is wonderful that you talked to doctors about everything. You present a really interesting question! 

For starters, swab tests work by taking a viral sample of DNA and testing it to see if it is HSV. Swab tests are prone to human error, since if the medical professional preforming the swab doesn't swab enough DNA, it can produce false negatives. 

The IgG and IgM blood tests work by detecting antibodies, so not the viral DNA itself like the swab test, but instead the antibodies your body builds up in response to HSV. Blood tests can of course be inaccurate as well, depending on timing and how quickly your body build up antibodies. 

It is possible to have both an HSV outbreak (in this case a primary outbreak) AND a yeast infection at the same time. Your swab came back positive, and it is possible that you have HSV and sadly also had a yeast infection, which would make sense because intercourse can cause a flare-up of yeast infection issues, as you described, since new bacteria is entering the body/moving around from your partner to you.

If you would like, totally get a blood test for extra knowledge. Knowledge is power! For your own peace of mind and for own physical health peace of mind, it might be a good idea. 

Also, to clarify, when you had the first outbreak, you had sores, correct? The antivirals didn't help so you took the Prednisone and it helped. It would make sense if you had an outbreak and a yeast infection simultaneously. 

I hope this helps!! 

Sending good vibes and blessings of health and happiness your way ☀️

Sorry, I didn't see this right away! To answer your questions, when I first had the outbreak, I started to notice raised bumps that I thought were sores, but it sounds more likely that they were normal bumps that got irritated (maybe from yeast and/or HSV?). The dermatologist and naturopath both looked at the bumps I was noticing and said they were normal but inflamed (not herpes sores). The dermatologist told me it's possible that I won't ever have an outbreak with sores, since some people don't. This leads me to wonder whether I had an outbreak at all, or if it was yeast the whole time? But from my understanding, you have to be having an outbreak to have a positive swab test. Do you know if that's accurate?

Neither the prednisone nor the antivirals made much difference with my irritation. The dermatologist sent me off with an anti-fungal cream that's been helping. I'm now on round two of fluconazole while also using the anti-fungal cream. I noticed a big improvement with the first dose, but I think I messed it up by accidentally eating some sugar. 

Thanks for your help! 

[Flowerteacher55]

Hi!!

No worries at all! 🙂 

I did some research, and I found a data table from the STD Center, NY which explains the accuracy of various herpes tests:

For the swab (culture), it said Test Accuracy = 100 ; False Positive Rate = 0% ; and False Negative Rate = usually 25%, but can be as high as 70%. So, a false positive for a swab would definitely be really unlikely. 

I honestly would have to ask a doctor about this, but asymptomatic shedding still can pass the virus, so that makes me wonder if the doctor/nurse swabbed an area where you were asympotmatically shedding, it would pick up the viral DNA and come back as positive. 

It's great that the cream has helped you! Sugar does feed yeast (sadness, because I am one of those people who snacks on cinnamon toast crunch all the time and each treats before bed) so that definitely can throw a monkey wrench into things. However, drink plenty of water and if you still aren't seeing improvement, head back to the doctor! 

Sending you happy healing vibes!