Please help my understanding of antibody testing

[Skippa]

Hi,

I'm trying to wrap my head around the usefulness of multiple antibody tests, beyond being able to say "yeah, you've been exposed to xyz".

Whilst I believe the methodology applies generically, I've put this in the Lyme forum because this relates to Lyme in my case.

I had the test, positive, got my abx, (most) symptoms went away, got the test again and "the second test confirms the first test".

All done, just had lingering symptoms that have got worse again the past couple months, so I'm having another blood test "to see".

To see what? My question is something like: "do they do a count of antibodies to see how 'strong' or 'active' the infection is"?

Eg, if you had antibodies last year, and got whatever it was treated "successfully" then would you expect another blood test this year to still show antibodies but in much fewer numbers?

Or is it more binary in nature? Eg "yes you got them or no you don't"?

Thanks for shedding some light

(This is based on my belief, possibly wrong, that once you've got certain antibodies then you'll have them forever, a few copies floating around just in case... which makes me question why bother checking for them... unless they're being counted?)

 

[Jonathan Edwards]

You cannot take an antibody level on its own to mean anything much, other than that there was an infection in the past. If an antibody level goes up that is evidence for there being active infection some time in between the two tests. But of course if the first test was done during the active infection then the level is likely to have still been going up at that point so a higher level later does not necessarily mean anything new. Antibody levels are only accurate to a factor of about two if done in different assay batches. So up to a doubling may be a random variation in the test performance.

 

[duncan]

Perhaps if we knew which antibody test(s) you had. They each present with different strengths and weaknesses. It may be that you used one that, going forward, can be employed as a baseline, and that would be good.

 

[Skippa]

@Jonathan Edwards thanks for the response. Makes me wonder why bother testing again?

@duncan sorry I don't know which test. "The standard first line NHS test" if that narrows it down? Also tested for HIV and other things (lots of checked boxes on the form).

I've got to wait 2 weeks to just get the blood taken anyways (yay underfunding) so if it is a live infection that delays any "early response".

 

[duncan]

If memory serves me, the standard NHS Lyme test is the C6 Peptide. When you got bit will matter, too, as testing too early may negate the process - so that may be an issue for the first time you were tested.

Let's assume that you were infected more than 30 days or so before the first test.

I may have this wrong, but from what I remember, if the C6 picks up the strain (if you are infected with Lyme), it kind of acts similar to testing for syphilis (btw, both syphilis and Lyme are spirochetal infections) in that your values should, with treatment, decline either fourfold, or back to normal levels.The caveat here is that that claim hold trues for early Lyme and early disseminated, not necessarily for late stage Lyme. But even for late stage Lyme your values SHOULD decline somewhat upon successful treatment (worst case, stay level).

So, finding out what your C6 value is can be important. If it's the C6, that is. I'd inquire either way. And either way, it may be a good exercise to compare the two results you've had so far, and keep them in mind for future tests.

 

[pattismith]

Here you can find antibodies (IgG and IgM) curves post lyme infection:

Serological follow-up after treatment of patients with erythema migrans and neuroborreliosis.
...........During follow-up, the majority of patients had developed negative or significantly declining IgM ODs after 1 to 1.5 years but persistently positive IgM ODs were found up to 17 months after treatment of erythema migrans and 3 years after treatment of neuroborreliosis. IgG antibody levels declined more slowly and remained elevated to a larger extent, but more than half of the patients had developed negative IgG ODs within 5 years after therapy. However, positive IgG OD values were found after 9 to 10 years for patients treated for neuroborreliosis as well as erythema migrans........

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC264030/

Another serologic follow up here too:

Long-term serological follow-up of patients treated for chronic cutaneous borreliosis or culture-positive erythema migrans. (Elisa IgG)

"Nearly three-quarters showed a clear decline in IgG levels over the years, while the rest did not. After 9+/-1 years 88% of 16 patients examined were still IgG positive. In conclusion, treatment of erythema migrans should be initiated on clinical appearance as a substantial number of patients stayed seronegative. Treatment success may in part be monitored serologically for both seropositive erythema migrans and chronic cutaneous borreliosis as most patients show declining titres after successful treatment. However, continuously high titres do not necessarily indicate treatment failure."


https://www.ncbi.nlm.nih.gov/pubmed/11200835

 

[Skippa]

Wow thanks for all the infos folks!

I'm now depending on these tests having just been utterly invalidated by my GP.

Went in complaining of my rash, for which I have photos, and neurological tongue and neck stiffness, and a burning/itchy forehead (weird, may not be related) and got offered DOUBLING MY SSRI DOSE!!

This is utterly disgusting.

Get this, he said "it's weird, very odd indeed, I wouldn't like to do anything before we get the bloods back" ... "but how about we up your SSRI dose because there's bound to be anxiety present."

(I declined btw)

What the actual F?

It's nothing short of upsetting. It all started like this last year, exact same, bloods PROVED I had Lyme and the abx mostly cleared it up. It's like that never happened, back to the old "it must be anxiety" thing again. Grrr.

(To be clear, I'm not convinced it is Lyme this time, lord knows I have other drug related things going on that might cause it, but to be invalidated and suggesting SSRIs for physical complaints is ...)

Phew, rant over, had to get it out.

I could almost imagine the doctor thinking "MUS, MUS, MUS" the whole time.

Why do they guard anti biotics like they're the crown jewels, but hand out seriously consequential drugs like SSRIs like they're candy?

 

[bombsh3ll]

I'm sorry you had a rotten experience with your GP.

Lyme is tricky as antibodies can hang around long after treatment whether successful or not - like antibodies to other infections or vaccines such as measles. Testing is also inaccurate - I myself would like to exclude Lyme but do not feel there is a currently worthwhile test, partly due to low sensitivity but also because even if positive, adequate treatment for anything but the early stage of lyme with a typical rash, is not accessible in the UK.

There is also post lyme syndrome where damage caused can persist even after successful eradication, particularly if it had progressed to a late stage such as neurological involvement.

Why do they guard anti biotics like they're the crown jewels, but hand out seriously consequential drugs like SSRIs like they're candy?

This made me smile (I am a GP). I guess excessive prescribing of antibiotics can harm many, due to drug resistant bacteria being on the rise and few new antibiotics in reserve, whereas injudicious use of antidepressants harms only that person and their loved ones. Not that that's an excuse.

 

[Maya24]

I also had my SSRI doubled as a first response.
My GP ordered an IG borelia burgdorferi test through the NHS. I had mine done at the hospital and they came back negative. (I had tick bite fever more than a decade ago while living in South Africa.)
Good luck with your blood tests and take care.