Conflicting Test Results

[nojo]

I've posted on this topic before, and I'm still confused by the conflicting results we continually receive. My daughter very often tests positive for strep on the rapid test, but when the long term culture comes back it is negative. Initially our pediatrician was telling us these were to be considered "false positives" most likely caused by the previous strep infection... there would be some left over cells in her throat but since they do not grow on the culture it is not an infection and therefore no antibiotics are necessary. I kind of understand that theory, but it doesn't totally sit right with me, here is why.

 

I took my daughter last week for a strep test and we had the same issue, positive rapid, 3 days later culture comes back negative. I have a hard time believing it was a true false positive because:

 

1. We had a negative rapid and culture one week prior, so no recent infection.

2. She was covered in strep rash, all over her trunk and face. (raised, dotty, sand-papery rash)

3. Her throat was sore.

4. Urinary frequency issues. (Going to the bathroom, leaving, turning right around, feeling like have to go again)

5. As the week progressed we started having more and more food issues (textures, refusing to eat, fighting every meal to get her to eat)

 

We did not have full fledged rages, but I think we caught this early. Many of these signs are classic for her, although on a much less severe scale.

 

What does this mean? Is she just so sensitive to strep that she is just exposed to strep (invasion not colonolized?) that even though she is not technically infected it is just the exposure that is causing her immune system to go haywire? What exactly is the mechanism that causes strep rash?

 

Does anyone else send out positive rapid tests for cultures? Do you get these wonky results?

 

Thanks!

[Kayanne]

Our pediatrician says that if you have a positive --it's positive. He said you either have strep or you don't..."no such thing as a little bit of strep...just like there is no such thing as a little bit of pregnant"

 

I am curious as to why the doctor keeps following up with a culture even when the rapid is positive? I thought the standard of care was to treat a positive rapid as an active infection, and a back-up culture is only needed if the rapid is negative, but a suspected infection is present. My doctor has never sent out a culture if the rapid is positive.

 

Has your doctor considered that maybe the lab is somehow messing things up, and would consider another lab.

 

Is your doctor sending out for a culture and sensitivity...maybe trying to get a hold on the particular strain and what antibiotic is most effective?

 

Certainly based on symptoms, I think you have an actual infection. Did you get at least 10 days of antibiotics?

 

I Think a strep rash is a reaction to toxins that the strep bacteria release...but I'm going by memory.

 

I hope this is helpful!

 

~Karen

[nojo]

Hi Karen,

 

It is just so complicated. For a long time, the rapid was proof enough for treatment. We were testing positive too often for rational explanation though. Our pattern is positive, 10 days antibiotics, approximately 2 weeks clean, and then another positive. We were averaging at least 10 positives a year if not more. The doctor then decided to start culturing to make sure we weren't one of the very rare false positives.

 

There are cases of false positives from what I can tell (from my google university degree!) I think you can have an overgrowth of staph bacteria in your throat, but why that would test positive on the rapid is beyond me. Anyhow, it is supposed to be exceedingly rare to have false positives on a rapid test. And for us to have this happen several times leads me to think something just isn't right. It has happened too many times for me to think lab error. It makes me think more along the lines of "It is one more sign her body is just not processing something correctly (or perhaps a better word would be in the typical way others do). "

 

We did the Cunningham test last fall, and I'm glad, she was 172, so I feel fairly certain that she does have PANDAS. Our lab results also show low IGG levels. I don't know if this is the component.

 

I feel like there is something I do not understand about this piece of the puzzle that could help me or others. I am not sure if anyone else has experienced this, or can explain what is going on to better. I do know that we can't even seem to be in a room full of kids without leaving with it.

 

Thanks -- Noelle

[Kayanne]

I am certainly NOT an expert...but what your describing to me sounds like one infection that NEVER cleared. I'm going by memory, (I'll look for it on the forum-I think Buster has posted this info), but to be fully sure a strep infection is cleared, you need to follow up with a strep test as far out as 21 days past the last dose of antibiotics.

 

Has your daughter ever been prescribed more than a 10 day course of antibiotics, and what type of antibiotic does your doctor normally prescribe?

 

I think you are absolutely correct in the assumption that her body is not processing something correctly...all of our kids have something going on...some more than others. That is why it is critical to treat a strep infection VERY aggressively...not like a normal infection. Longer and stronger antibiotics are needed.

 

 

 

Hi Karen,

 

It is just so complicated. For a long time, the rapid was proof enough for treatment. We were testing positive too often for rational explanation though. Our pattern is positive, 10 days antibiotics, approximately 2 weeks clean, and then another positive. We were averaging at least 10 positives a year if not more. The doctor then decided to start culturing to make sure we weren't one of the very rare false positives.

 

There are cases of false positives from what I can tell (from my google university degree!) I think you can have an overgrowth of staph bacteria in your throat, but why that would test positive on the rapid is beyond me. Anyhow, it is supposed to be exceedingly rare to have false positives on a rapid test. And for us to have this happen several times leads me to think something just isn't right. It has happened too many times for me to think lab error. It makes me think more along the lines of "It is one more sign her body is just not processing something correctly (or perhaps a better word would be in the typical way others do). "

 

We did the Cunningham test last fall, and I'm glad, she was 172, so I feel fairly certain that she does have PANDAS. Our lab results also show low IGG levels. I don't know if this is the component.

 

I feel like there is something I do not understand about this piece of the puzzle that could help me or others. I am not sure if anyone else has experienced this, or can explain what is going on to better. I do know that we can't even seem to be in a room full of kids without leaving with it.

 

Thanks -- Noelle

Edited June 7, 2010 by Kayanne

[Kayanne]

This was taken from Buster's thread of FAQ (pinned at the top):

 

"Q:Should I check for clearing of my non-PANDAS children if treated for strep

A: Yes. About 3 weeks after completing treatment for strep you can check for clearance by getting a negative culture. The dosing levels on antibiotics are designed so that about 80% of children with normal immune systems are cleared with a "standard" dosing of antibiotics. Some strains of strep are harder to eradicate and either longer treatments or use of antibiotics like azithromycin and augmentin seem to be effective on these strains."

 

Buster is careful not to post information if it doesn't have a source

[nojo]

Before we pulled her out of school at Thanksgiving we did several courses of antibiotics (We were almost on monthly full dose as it was) and then finally moved to prophylaxis before tapering off. We did seem to be clear and have several negative rapids and cultures when tested through the late winter and spring. We weren't were never sure if we weren't clearing the infection, or were being constantly reinfected either. I took this as a good sign that hopefully through the less exposure at school she was starting to do better. So this last little bit was very discouraging to say the least. Again, the rash leads me to believe she the infection (or at least exposure is real).

 

It is so frustrating isn't it! In my former life I was an art teacher, so reading all these scientific papers is using the opposite side of my brain. I so wish I could just piece this puzzle together for her and figure out the missing part, I just keep thinking if I could figure out how to help her to keep from getting sick in the first place.

 

Thanks, I really do appreciate you taking the time to listen to me think out loud. It always makes me feel better to remember I'm not the only one (even though I'm the only one around here)

[Kayanne]

Did her PANDAS symptoms improve after the longer course of antibiotics last year?

 

Was it several different antibiotic? or the same one?

 

I totally hear your frustration about understanding this...I'm a number cruncher, fiction reader, overall crafty person...this stuff is way over my head...but my obsessive tendencies won't let stop trying to learn all I can...

[norcalmom]

Did you draw titers and check for perianal strep too?

[nojo]

No, antibiotics have only been a band-aid for us. They did help, but for us we never could get well, and we did many different antibiotics, all full course. So far, the biggest help has been pulling out of the germ fest of school. She does have some other issues, severe asthma. Before taking the drastic measure of removing from school I had charted out all her positive tests over the last 2 years, compiled all antibiotic usage, asthma flares, prednisone usage (prescribed for asthma). She was on homebound for 5 months of kindergarten. After charting everything over the last 2 years the only times she showed any improvement was June, July and August and the time period she was on homebound instruction. Last year it became increasingly clear when she went to a one week day camp and had all the crazy ocd stuff/eating issues after one week, and she tested positive for strep, after only one week around others! That is when we started really making the PANDAS connection, when she couldn't sleep until the silverware drawer was sorted properly ( sobbing, crying hysterically, and that is when I knew she had strep again).

 

When she came off of homebound instruction, she only made it 2 weeks that year before getting sick, and having to pull out again to go back on homebound. It has helped significantly. She finally is not testing positive for the strep all of the time, that is what leads me to believe she did finally at some point clear the infection from before even if it did not earlier in the year. We have had many clear rapid tests and cultures this winter and spring, including the week before. So why now the positive rapid, and then the not positive culture?

 

I think I'm starting to ramble, I hope this makes sense.

[nojo]

Did you draw titers and check for perianal strep too?

 

We did titers once, and it came back she's never had strep. (I think we're the type that the titers don't seem to rise)

 

We didn't check for perianal, how would we do that? Do you swab them?

[colleenrn]

It sounds like she has strep based on all her symptoms. The lab could have made an error. OR, sometimes if it is intracellular strep, the swab must pierce the agar and maybe they did not do that? One more reason could be the nurse did not get a good sample. Did they do the two swabs separately or put them together and swab only once? That is risky when it is done that way b/c you do not get a good enough sample. Do you know if they swabbed both tonsils? I can't find the article now, but there was a study that showed in 20% of the cases, one tonsil can culture negative when the other cultures positive. Perhaps that was occuring and they only swabbed one tonsil.

 

I would, without question, treat for a positive rapid. We have gotten a positive rapid with a negative culture, but my physician said it was for sure positive and should be treated.

 

What antibiotics do you use?

Colleen

[nojo]

It sounds like she has strep based on all her symptoms. The lab could have made an error. OR, sometimes if it is intracellular strep, the swab must pierce the agar and maybe they did not do that? One more reason could be the nurse did not get a good sample. Did they do the two swabs separately or put them together and swab only once? That is risky when it is done that way b/c you do not get a good enough sample. Do you know if they swabbed both tonsils? I can't find the article now, but there was a study that showed in 20% of the cases, one tonsil can culture negative when the other cultures positive. Perhaps that was occuring and they only swabbed one tonsil.

 

I would, without question, treat for a positive rapid. We have gotten a positive rapid with a negative culture, but my physician said it was for sure positive and should be treated.

 

What antibiotics do you use?

Colleen

 

They did the 2 swabs at the same time. We have had her tonsils removed a few years ago. We started the antibiotics (Keflex) and I continued to treat for the full ten days even when her culture came back negative.

 

Could she have just enough strep in her throat to test positive for the rapid test (not enough for there to be a full infection) but because she is sensitive to strep her body is already making the auto immune antibodies causing the PANDAS type reaction? She would have to have enough of the strep in her to cause her body to react and cause the rash. If she had the perianal strep, we wouldn't have the positive rapid test at all.

 

I know Buster has talked about the four stages of strep, could the rapid test show one versus the culture another?