Reading your bloods: what your immune cells are trying to tell you
Very often when I ask clients for blood test results, I hear “ Oh it’s fine, the doctor said they were all normal”. I still like to look at these blood results, as, often it is normally, technically, within range. But normal and optimal aren't always the same thing, and there's a surprising amount your white cells in particular can tell a practitioner about what's going on with your immune system, long before anything tips into "abnormal" on a standard report.
Red blood cells: not just about oxygen
Erythrocytes, your red blood cells, are the most abundant cell type in your body, and most of us only think of them in terms of carrying oxygen around. But they're also doing quiet immune work. Damaged red cells trigger an innate immune response, they carry surface receptors that bind to antibodies, and they even have some antimicrobial function of their own.
The optimal range sits at 3.8 to 5.2 for women, 4 to 5.9 for men, and I'm always looking for someone to sit in the middle of that range rather than skimming the bottom edge of "normal." Even subclinical anaemia, still technically in range but on the low side, is worth taking seriously, both for energy and for immune resilience. Levels naturally decline a little with age, and raised levels can point to dehydration, stress, a need for more vitamin C, or asthma.
White blood cells: your immune activity dial
Your total white cell count is really a sum of several different players: neutrophils, lymphocytes, monocytes, eosinophils and basophils. As a general guide, I like to see this sitting around 5 to 6, with anything above 7.6 suggesting some degree of immune activation, even if it's not yet flagged as abnormal.
Higher counts, above 11, tend to show up with physical exertion, acute stress, active infection, a flare of inflammation, or starting steroid medication. Low counts, below 4, are a different story altogether and can point towards autoimmunity, nutritional deficiency, chronic viral or spirochete infection (Lyme disease is one example), overwhelming bacterial infection, severe chronic stress, bone marrow issues, or immunosuppressant medication.
If eosinophils or basophils are running high specifically, that's usually your allergic tendencies talking, think hayfever and similar reactions.
The lymphocyte detail most people never hear about
This is where it gets interesting. Lymphocytes split into B cells and T cells, plus innate lymphoid cells like natural killer (NK) cells.
B cells are your antibody factories. T cells mature in the thymus gland, where they essentially learn to tell "self" from "stranger," and then go hunting for antigens using specialised receptors. T cells further divide into T helper cells, marked by a protein called CD4, and cytotoxic T cells, marked by CD8.
In healthy blood, the ratio of CD4 to CD8 cells sits at roughly two to one. When that ratio shifts, it's a meaningful clue, showing up in immunodeficiency conditions, autoimmune disease, ageing, and general inflammation. A lower ratio than expected suggests immune suppression, and tends to appear alongside chronic or acute infection, or in the context of cancer.
T helper patterns: a map of what your immune system is fighting
This is the part I find most useful clinically, because different patterns of T helper cell activity point towards quite different underlying pictures.
Th2 dominance tends to show up with allergies and parasitic infection, so think allergic rhinitis, hayfever, atopic asthma, mould exposure, or a heavy environmental antigen load.
Th1 dominance leans towards viral infections, certain bacterial infections, and, at the more serious end, cancer, usually alongside a notably high white cell count. Confusingly, Th1 activity can also look low in the context of chronic infection, alongside a low white cell count, so context always matters more than a single number.
Th17 dominance points towards dysbiosis, urinary tract and other bacterial infections, autoimmunity (often driven by a long-standing antigen burden), and fungal or yeast involvement. A pattern of low NK cells alongside elevated Th17 can suggest viral involvement, or presentations linked to mould exposure or Lyme disease.
More specialist testing, such as that offered through Lab4More, can map these patterns in far more detail than a standard NHS full blood count, which is worth knowing about if you've been told everything is "normal" but you still don't feel right.
The most important caveat
None of these patterns exist in isolation, and I want to be honest about that rather than making it sound like a simple lookup table. Most people I see in clinic have several of these threads overlapping at once, a bit of gut dysbiosis alongside an old viral trigger, alongside a stress response that's never quite reset. Reading bloods well means holding all of that complexity at once, not hunting for one tidy answer.
That's really the thread running through this whole series. Your immune system is not malfunctioning at random. It is responding, sensibly, to a set of signals, and the job of good practitioner work is figuring out which signals are still switched on and why, then giving your body what it needs to properly complete the job of switching them back off.
If you've had bloodwork come back "normal" but you still don't feel like yourself, that's exactly the kind of pattern I'd love to help you look at more closely. Get in touch and let's take a proper look together.