🛡️ Frequent Illness & Immune Resilience
For everyone · 8 markers · $97.65
with code CAMERON $108.50
Catching everything going round, infections that drag on for weeks, wounds or mouth ulcers that heal slowly, or cold sores that keep recurring.
🩸 Order this exact panel — 10% off
All 8 markers load into your cart in one click. No doctor's visit, drawn at any Quest location in the US, results by email in about two weeks. Code CAMERON applies automatically.
Add all 8 markers — $97.65 → Open the full Bloodwork Vault →Why this panel
Most people who get sick constantly don't have a broken immune system — they have one or two correctable deficiencies, an untreated metabolic problem, or they're simply run down. This panel checks the fixable causes and screens the blood counts that would suggest something more serious.
What this panel can settle, and by what logic
Eight tests, and their job is to find the small number of ordinary medical reasons an adult catches everything going round. Three of the eight carry almost all of that yield.
- The differential on the Complete Blood Count (CBC) with Differential is the highest-value line on the panel. Not the white count — the breakdown. A persistent lymphocyte count below roughly 1.0 x10⁹/L, or a neutrophil count below 1.5, is an objective abnormality and the single finding here that would send you to an immunologist Allaoui 2022.
- HbA1c (Hemoglobin A1c) is on an immunity panel because hyperglycemia is a real and reversible cause of recurrent skin, urinary and respiratory infection. An HbA1c of 7.8% explains a pattern of infections that no amount of zinc will fix — while noting that HbA1c is also a red-cell measurement and iron deficiency shifts it independently of glucose Chen 2022.
- Ferritin with hs-CRP (High-Sensitivity C-Reactive Protein) and ESR (Sed Rate) answers a different question than it looks like. Iron deficiency impairs immune function, but ferritin is also an acute-phase protein, so the CRP on the same tube is what makes the ferritin readable Luo 2023. There is still no single global ferritin threshold for deficiency Cancado 2025.
- Vitamin D (25-Hydroxy) and Zinc, Plasma are the two nutrients with actual infection trial data behind them, which is why they are here rather than a longer nutrient list Jolliffe 2021.
What it cannot settle, and what would
It cannot diagnose an immune deficiency, because it does not measure antibodies. The tests that do are serum IgG, IgA and IgM, specific antibody titers to tetanus and pneumococcus, and lymphocyte subsets — none of which is on this panel. Selective IgA deficiency is the commonest primary immunodeficiency in adults and is completely invisible to every marker here Allaoui 2022.
It cannot tell you that your infection rate is abnormal. Adults average two to three upper respiratory infections a year, and more if they live with young children. The clinical thresholds that justify an immunology workup are pattern-based — deep or unusual sites, organisms that should not cause disease, infections needing intravenous antibiotics, failure to clear — not a count of colds Allaoui 2022.
Correcting Vitamin D (25-Hydroxy) will do less than the marketing suggests. In pooled randomized trials 61.3% of participants given vitamin D still had at least one acute respiratory infection, a statistically significant but small reduction against placebo Jolliffe 2021. It is worth correcting a real deficiency; it is not an immune strategy.
And a plasma zinc is a weak measure of zinc status. Plasma zinc responds to a recent meal, to the time of day and to inflammation, and reflects body stores poorly Ceballos-Rasgado 2024. A borderline-low result here is not evidence you are zinc deficient.
Draw conditions that decide whether the money is wasted
Four conditions, and the first one decides whether the other seven markers say anything.
- Wait 2 to 3 weeks after the last infection. Testing while you are unwell measures the illness: the differential shifts, CRP and ESR rise, ferritin rises with them Luo 2023 and plasma zinc falls as part of the same acute-phase response Ceballos-Rasgado 2024. Every one of those moves in the direction that produces a wrong conclusion.
- Morning and fasted for the zinc, not just for the glucose. Plasma zinc falls after a meal and drifts across the day, so a mid-afternoon post-lunch sample is the version most likely to read falsely low Ceballos-Rasgado 2024.
- Insist the sample is not hemolyzed. Red cells are rich in zinc, so a traumatic draw releases it into the serum and produces a falsely reassuring result; sample handling and delay to centrifugation move several nutrition biomarkers on their own Abraham 2019.
- Take the Vitamin D (25-Hydroxy) seasonally, and from the same lab. Between-laboratory variability in 25-hydroxyvitamin D is measurable Wise 2021, so a winter result from one lab against a summer result from another is two errors stacked on a real seasonal difference.
How you would know it answered your question, and what each pattern means next
Five results, with the interval each earns.
- Lymphocyte or neutrophil count low on two draws 4 weeks apart: the one result here that goes to a clinician rather than a supplement — ask for immunoglobulins and specific antibody titers Allaoui 2022.
- HbA1c (Hemoglobin A1c) of 5.7% or above: treat this as the answer until proved otherwise and recheck in 3 months, which is one red-cell lifespan and the shortest interval at which HbA1c means anything new Chen 2022.
- Ferritin under 30 ng/mL with a normal hs-CRP (High-Sensitivity C-Reactive Protein): real iron deficiency. Treat and retest at 12 weeks, not at 4, because stores refill over months Cancado 2025.
- Vitamin D (25-Hydroxy) below 20 ng/mL: correct it and recheck at 3 months, when a daily dose has reached steady state. Expect better numbers, not obviously fewer colds Jolliffe 2021.
- All eight normal and you are still ill every month: the panel worked, and the next step is a description of the infections rather than another blood test — site, organism, severity and whether they clear Allaoui 2022.
Sources read for these sections
- Allaoui A, et al. When to suspect an immune deficiency in adults?. La Tunisie Medicale 2022 · PMID 36571726
- Jolliffe DA, et al. Vitamin D supplementation to prevent acute respiratory infections: a systematic review and meta-analysis of aggregate data from randomised controlled trials. Lancet Diabetes and Endocrinology 2021 · PMID 33798465
- Ceballos-Rasgado M, et al. Methods of Assessment of Zinc Status in Humans: An Updated Review and Meta-analysis. Nutrition Reviews 2024 · PMID 38917458
- Luo H, et al. A Practical Guide to Adjust Micronutrient Biomarkers for Inflammation Using the BRINDA Method. Journal of Nutrition 2023 · PMID 36792034
- Chen Z, et al. Interpretation of HbA1c lies at the intersection of analytical methodology, clinical biochemistry and hematology (Review). Experimental and Therapeutic Medicine 2022 · PMID 36382101
- Wise SA, et al. Vitamin D Standardization Program (VDSP) intralaboratory study for the assessment of 25-hydroxyvitamin D assay variability and bias. Journal of Steroid Biochemistry and Molecular Biology 2021 · PMID 34010687
- Cancado RD. Defining Global Thresholds for Serum Ferritin: A Challenging Mission in Establishing the Iron Deficiency Diagnosis in This Era of Striving for Health Equity. Diagnostics (Basel) 2025 · PMID 39941219
- Abraham RA, et al. Effect of temperature and time delay in centrifugation on stability of select biomarkers of nutrition and non-communicable diseases in blood samples. Biochemia Medica 2019 · PMID 31223262
The 8 markers — and why each one is here
White cell lines and the neutrophil-to-lymphocyte ratio — the core immune screen
Raised glucose measurably impairs neutrophil function — the unexpected one
Ongoing inflammation suggests something specific rather than 'run down'
Liver, kidney and protein status all affect immune competence
Ordering the panel tells you your numbers. The protocol tells you what to do with them — why recurrent infection is usually an under-resourced immune system rather than a broken one, the HbA1c finding that catches undiagnosed diabetes, and the free globulin check hiding on your CMP.
Join Skool — $10/mo →What this panel is ordered to decide
A panel is a set of numbers until it settles something. These are the decisions this one feeds — each links the pathway it belongs to, what that pathway claims, and what its test list is read for.
Neutrophil count and CRP describe the innate system's resting state. Vitamin D drives the antimicrobial peptides this arm depends on, which is much of why status tracks with infection rate.
The differential white count separates viral from bacterial better than how you feel does — and it decides whether anything in this pathway is even the right category.
The lymphocyte count is the one readable output of thymic function available on a routine panel — worth a baseline before and after a cycle, since it is the only way you'd know whether anything happened.
The lymphocyte count on a standard full blood count is a free read on adaptive immune capacity. Persistently low, with low zinc or vitamin D, is the most correctable part of immune ageing.
Secretory IgA is the first line and it is vitamin-A dependent. Around 70% of immune tissue sits along the gut, which makes this the least glamorous and most leveraged part of immunity.
Related panels
Frequently asked questions
8 markers: Complete Blood Count (CBC) w/ Differential, Vitamin D (25-Hydroxy), Zinc, Plasma, HbA1c (Hemoglobin A1c), Ferritin, hs-CRP (C-Reactive Protein, High Sensitivity), ESR (Sed Rate, Westergren), Comprehensive Metabolic Panel (CMP).
$108.50 before discount, $97.65 with code CAMERON applied automatically. Individual markers add a one-time $10 draw fee. Ordered through Marek Diagnostics and drawn at any Quest Diagnostics location in the US.
No. These are ordered direct-to-consumer through Marek Diagnostics — you order online, walk into a Quest location, and results are emailed to you in about two weeks. No physician visit or insurance required. Not available in NY, NJ or RI.
Fast 9–12 hours for the glucose. Wait at least 2–3 weeks after an infection — testing while you're actively unwell gives you the picture of being ill, not your baseline.
Low vitamin D or zinc → correct and reassess, these are the common wins. Raised HbA1c → glucose control is impairing your immune function. Low ferritin → iron deficiency impairs immunity independently of anemia. Persistently low white cells or lymphocytes, or an unexplained raised ESR, needs a doctor rather than a supplement.
Where this goes next
This page is how to read the panel. What to DO about each result — the dosing, the order to correct things in, the week-by-week schedule and what to retest — is a lesson inside Skool.