Hi Portacrean,
No, nothing to be wondering about blood test results being negative for H.pylori, biopsie H.pylori positive, WBC normal.
There is hardly anything in lab tests, that is 100% to be taken black and white, it always is just a helping tool in the big picture, and it highly depends which test we are looking at,
and so is also the fact of when and where a sample is taken (be it biopsie location, depths, or for blood the timing e.g. diagnostic window)
and your very own individual response to something anyway, which can be very different from individual to individual.
I just got to know a patient, who had pneumonia (finally diagnosed in xray) but had no fever, which is one of the prime symptoms, hence the delay.
It is possible though.
Regarding lab tests:
it's called 'SPECIFITY' and 'SENSITIVITY' of a test method, that a test can be false positive or false negative (despite the fact, that the sample itself can actually represent wrongly and the test be correct)
Always the best compromise is used, also depends if a screening should rather pick up with high sensitivity rate (hence risk of false positive results) anything possible or be specific already (risk of false negative results); lab tests are constantly replaced if a better one comes up regarding specifity and sensitivity depending what is needed, this is a big field and I don't go in further details.
Regarding H.pylori
there are histology, culture, rapid urease, PCR, serological blood, Carbon urea breath test, stool as diagnose tools.
ALL those are luckily high in sensitivity and specifity!!
So they dedect small amounts and if positive is H.pylori and not something else. But 'small amounts' can still be too little.
Regarding YOUR BLOOD TEST, I don't know which blood test it was, there are some different ones, but they all look for your immune response, a protein, that your immune system produces after contact with H.pylori. Now, your production can be too small or at the time of sampling having been too little because of being too early (and would be detectable now?).
Also the blood antibody IgG ELISA test itself e.g. has a sensitivity of 95%, which is really good, other tests like latex agglutination are 93% sensitivity, specifity 95%.
But see, not 100%.
HENCE you can have a false negative H.pylori blood antibody test and still actually be infected with H.pylori. Unlikely, but possible.
That's why we don't give up right there if symptoms persist.
You got a BIOPSIE tested for it! If cultured, rapid urease, whatever the test was, it was positive and you can due to the specifity trust this result.
the blood test was for whichever possible reason (and it is possible) false neg at it's time of sample taking or will always be neg.
Out of a scientific interest it would be interesting if your antibodies showed up now, too, or still neg (then this would be no test for you ever for follow ups), if a breath test would show up positive.
This 'blood neg, biopsie pos' is hence plausible. Same happens with celiac, hence biopsies are so needed. Hence we never rely on one test if symptoms say different.
The carbon urea breath test is btw - if done correctly and not after an antiacid or antibiotic treatment, wait 4 weeks- very accurate!!
So is the stool test.
I am not sure why a blood test was the first choice for your doc. But he persisted (or you), so all good.
Now to the WBC:
H.pylori causes a chronic infection of your stomach lining.
Infection fighting white blood cells move to the stomach, they go there (not the H.pylori into blood), see it as an intrudor = produce antibodies, that you can find in the blood (usually in measurable levels)....duhduh,
so yes, the WBC should be higher.
Yes, and it often is,
BUT IT OFTEN IS NOT,
since the other theory is, that the H.pylori do not enter the blood stream itself. There are studies that show, that WBC do rise and correlate with what is found in the biopsie (distribution of white blood cells), other studies show, that some are 100% (breath test, biopsie stain, culture) H.pylori infected and have a normal WBC.
Another study shows a coexistence of elevated WBC and H.pylori infection increased the risk for gastric cancer.
Happy now to have normal WBC? ;-)
All these constellations are very possible and plausible.
The WBC is just one piece in a puzzle, the WHOLE picture with your history and other test results gives the answer, not a single out one, especially if it sounds a bit contradictory, which is still plausible.
WBC is very helpful, but not the gold standart to tell you, if you have H.pylori or not.
I am very happy for you that you have a stomach sample positive and treatment could start, the specifity is very high to be correctly diagnosed with H.pylori from the biopsie sample.
After the treatment you see, you experience, if it helped or not.
Don't forget: sometimes we have a combination of things happening, good to tackle one but might not be everything done and dusted then.
(also one can get re-infected....)
All the best!!!!