Blood cells, and the counting thereof.

Not seeking medical advice, just satisfying curiosity.

I just had my physical, and the doctor had a mess of blood tests, of course. I took a look at the results myself, and they had “absolute lymphocytes: 560” marked as “low”, with a normal range of 850 - 3900. OK, that DOES sound a bit low, but the doctor didn’t mention it - he just said something about my cholesterol (sort of high) and vitamin D (sort of low) - about par for the course. When I checked back with him, he said that the lymphocyte count wasn’t “medically significant” (relayed through his receptionist, not a direct answer from him). OK, I’ll believe him, but I wonder why, given that the doctor normally seems to be a bit of a worry wart about test results.

Looking closer, I note that everything else on the entire CBC seems to be on the low end of normal, except “absolute neutrophils” which is about in the middle, so that I have a nuetrophil percentage of 82%, and a lymphocyte percentage of 10%.

OK, what’s up with that?

Mild lymphopenia or lymphocytopenia (mild low blood lymphocyte count) is very common and often is seen during and following viral illnesses such as the common cold.

The level may also go down with “stress” in general, possibly as a result of cortisol production by the body in response to the stress (with cortisol being an ‘anti lymphocyte hormone’).

Extremely low lymphocyte counts can be seen in HIV/AIDS, cancer of the lymph system (lymphoma), lupus and other autoimmune conditions, and people on chemotherapy.

I usually ignore mild lymphopenia unless there are reasons to suspect any of the serious causes above.

Hmmm. You mentioned “viral illnesses”. Something I was actually wondering about before going in to have the blood drawn - I’d just gotten the shingles vaccine a bit over a week before the test. I think I even asked about that at the lab, and they said “nah, that’s OK”. The shingles vaccine is a live vaccine, and it did swell up a bit for a couple days. Is that a good explanation?

When an automated test flags a result like that, it’s so that the doctor can look at it and see if it’s a problem. It’s not telling the doctor that there IS a problem. Limits tend to be on the conservative side, so they don’t miss anything, which means that a lot of results will be flagged that are really just fine.

Indeed it is (IMO). Much of your body’s response to the vaccine is identical to what it does upon being exposed to the disease-causing virus including the production of cytokines (chemical signals responsible for, among other things, regulation of lymphocytes) such as interferon* .

*link goes to cite showing lymphopenic effect of interferon

Regarding the remainder of your results, I was taught a helpful adage: a low/high normal is still normal.