7 Novel Laboratory Tests to Assess Immune Function

Mar 21, 2024 | Written by Matthew Lees, PhD | Reviewed by Scott Sherr, MD and Marion Hall

7 Novel Laboratory Tests to Assess Immune Function

The immune system defends the body against infectious agents, pathogens, environmental threats, and helps repair injuries [1]. It comprises a multi-pronged battery of anatomical physical barriers (i.e., skin, mucous membranes, epithelial cells) and two downstream systems called the innate and adaptive immune systems.

Innate immunity has a rapid response and utilizes receptors to recognize invading particles. It is an immediate defense that is not as specific as antigen receptors, whereas adaptive immunity is specific to T and B cells. These cells recognize specific antigens on the invading microorganism and produce antibodies that target and destroy them.

Given the vitally important role of the immune system in overall health, it is crucial that its function be optimized and numerous testing methods can be used to monitor how well it's working. This article aims to enumerate these important methods and discuss how they can be used to improve or optimize immune function to promote better health.

1. Complete Blood Count

One of the most common laboratory tests performed today, the complete blood count (CBC) profiles the total numbers and characteristics of cell components in a person’s blood [2,3].

The white blood cell (WBC) count with differential determines the total number of WBCs (also called leukocytes) and the percentage of each type [2]. Leukocytes fight infection, and five different sub-populations have specific roles: neutrophils, monocytes, basophils, eosinophils, and lymphocytes (B cells, T cells, and natural killer cells). These WBCs make up a small percentage of blood volume (around 1% in a healthy person) and are responsible for finding, binding to, and destroying pathogens and external threats [4].

Abnormal findings from the CBC can be indicative of various conditions or ailments, therefore testing of this kind can be extremely informative for health and wellness.

2. General Micronutrient Testing

Our historical understanding of immune support by micronutrients relates to vitamin C deficiency and supplementation in times of scurvy centuries ago (and those pesky pirates, of course). We now appreciate that the complex, integrated immune system requires various micronutrients including vitamins A, C, E, D, B6, and B12, as well as trace elements such as folate, zinc, iron, copper, and selenium [5].

Micronutrients influence and support every stage of the immune response, with deficiencies leading to immunosuppression of the innate and adaptive immune systems and therefore increasing the susceptibility to infection. The specific micronutrients with the strongest evidence for their role in immune function are vitamin C, vitamin D, and zinc [5].

Testing for micronutrient levels can be a very useful procedure in highlighting deficiency or excess, in order to make direct dietary changes to optimize these levels to benefit immune function. One of the best ways is by using metabolomics and organic acid testing. You can go to HOMeHOPe for more information on this.

3. Hormone Optimization

Concentrations of certain hormones are particularly relevant to immune function, and optimization of these is crucial for both immune and general health. Take testosterone for example, the male sex hormone, wherein low serum levels can cause an impaired immune response to infection and an increased likelihood of hospitalization and all-cause mortality [6]. Conversely, levels of testosterone that are too high can reduce the efficiency of the immune response to vaccination [7]. Not incidentally, autoimmune disorders are higher in women than men, at least in part, due to their lower testosterone levels. 

Separately, the concentration of growth hormone, a peptide hormone that plays an essential role in maintaining tissues and organs across the lifespan, is implicated in immunoregulation, the stimulation of T and B cells, as well as antibody production [8].

Therefore, optimizing the levels of these hormones through the use of tests and the support of a physician can be of great value to immune system optimization.  

4. Oxidative Stress Testing

Reactive oxygen species (ROS) are molecules that form as byproducts of aerobic metabolism (the generation of cellular fuel in the presence of oxygen), a process that modulates immune system function [9]. An abundance of ROS can lead to oxidative stress, an imbalance between ROS production and the body's ability to eliminate them by protective methods (e.g., antioxidants) [10,11].

Although ROS can play an important role as signaling molecules in metabolism, a state of oxidative stress is closely related to the activity of the innate immune system and the promotion of inflammatory and DNA-damaging processes [12,13].

Oxidative stress testing examines bodily fluids such as blood and urine for the presence of ROS, antioxidants, and their state of balance in the body. For instance, blood levels of glutathione (an antioxidant) could be analyzed, as well as urine concentrations of 8-hydroxyguanosine (a marker of RNA damage resulting from oxidative stress) [14]. This type of testing battery can then help direct treatment, often in the form of nutritional optimization.

5. Vitamin D Assessment

It is well known that vitamin D plays an important role in the maintenance of skeletal health, yet it also has broad and far-reaching effects on other systems of the body, including the immune system [15-17].

Vitamin D is involved in the production of antimicrobial peptides from immune cells, as well as from epithelial cells in the respiratory tract [1,18,19]. Lower levels of vitamin D are associated with an increased susceptibility to viral infections such as influenza. Unfortunately, vitamin D deficiency is prevalent due to insufficient consumption from dietary sources and not getting enough sunlight (the principal source).

Testing of serum vitamin D levels can help direct supplementation strategies if needed and represent a very useful tool given the role of vitamin D in immune function and general health.

6. Inflammatory Markers

Many biological markers provide useful information on the extent of inflammation. Although beneficial in the short term, chronic inflammation is associated with a host of metabolic and other serious diseases/conditions.

A key marker that is widely used to assess low-grade chronic inflammation is the C-reactive protein (CRP) [20]. It can be measured accurately to identify individuals in this state [21].

7. Insulin Resistance

Insulin is a vital hormone that is implicated in nearly all cellular processes. While heavily studied in the context of the liver, skeletal muscle, and fat cells, immune cells also rely on insulin for their metabolic requirements and function [22].

In insulin resistance, the cells of the body do not respond as efficiently to the circulating insulin, forcing the pancreas to produce more of it to achieve the same effect. This is referred to as impaired insulin sensitivity. Insulin resistance is a leading cause of several metabolic diseases, as well as elevated blood glucose (sugar) levels which over time can cause type 2 diabetes.

One method in which the presence of insulin resistance is assessed is the HOMA-IR test [23], which requires blood glucose and insulin concentrations in the fasted state to generate an output number.


In this article, we identified some novel and extremely useful testing targets and methods to inform the effectiveness and efficiency of the immune system.

Some of these methods assess the general state of the system itself, such as the complete blood count and inflammatory markers, whereas others examine the levels of micronutrients, hormones, and other diet-derived factors in the blood.

While any one of these methods can give helpful insights into the function of the immune system, several methods often need to be employed to give an overall picture, with the support of a qualified physician.

If you're looking for an easy way to give your immune system a much-needed boost, check out Tro Mune, our health optimization troche for immune support that will swap your endless colds and constant inflammation for an immune shield of unmatched power and resilience. Take it before bed because it increases deep sleep too! 



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