Cytokines are important biomarkers of immune system activity, with dynamic fluctuations that reflect states of inflammation, infection, immune response, and other pathological conditions. Cytokines can also function as therapeutic agents and targets, highlighting their importance in clinical applications and drug development. Profiling cytokines can help illuminate the in vivo mechanisms of emerging therapies and uncover potential cytokine-mediated toxicities. The ability to compare cytokine signatures across clinical studies can also reveal patterns of off-target activity, particularly in the context of advanced immunotherapies (such as in cell and gene therapies). In this article, we examine some key challenges in cytokine detection and share expert perspectives on best practices for obtaining reliable results.

Working with complex samples

When selecting an assay, one of the first questions to ask is whether the detection method is compatible with your sample type. This consideration becomes especially critical when analyzing complex or clinically derived specimens such as blood, tissue, or other bodily fluids. In clinical samples, cytokines are physiologically produced at low concentrations, act primarily in localized environments, and often contain components that can interfere with immunoassay performance. “For more complex biological sample types, such as serum and plasma, assay interference from factors in the sample matrix can undermine performance and require significant sample dilution,” notes Dan Lazar, Senior Research Scientist of R&D Assay Design & Sample Analysis at Promega Corporation.

Common sources of interference include soluble cytokine receptors, anti-cytokine autoantibodies, and other endogenous antibodies that cross-react with assay reagents. Additional confounders such as rheumatoid factors and heterophile antibodies can also produce misleading signals or binding competition. High-titer autoantibodies to cytokines, in particular, can significantly distort quantitative results. Finally, the presence of therapeutic biologics that target cytokines or their receptors may further complicate analysis by directly competing with detection antibodies within the assay.

Users should be aware of any potential confounders that may be present in their sample and take precautions, such as including additional controls. “Verifying expected cytokine recovery when spiked into the intended sample matrix is always a good idea, especially if not demonstrated by the assay provider,” says Lazar.

If facing significant interference, consider supplementing cytokine measurements with surrogate biomarkers, such as cytokine-responsive gene products, to provide a more comprehensive and reliable assessment. Examples include cytokine-induced inflammatory markers like C-reactive protein (CRP), which can serve as indirect indicators of cytokine activity.

Options for multiplexing

The ability to measure multiple cytokines simultaneously is a common need among researchers, particularly when increasing throughput or working with limited sample amounts. Although traditional ELISAs remain the gold standard for quantifying individual cytokine targets, a range of multiplexing platforms now enable the parallel detection of multiple analytes within a single sample. These include bead- and array-based multiplex immunoassays, immuno-PCR, and flow cytometry-based platforms, among other technologies. Each approach offers distinct advantages and potential limitations that researchers should evaluate in the context of their specific goals and constraints.

“When efficient determination of multiple cytokine levels is desired, available multiplex formats can be quite effective, but cost, throughput, and the requirement for specialized instrumentation can be an important consideration,” notes Lazar at Promega. “Certainly, for high-throughput screeners, robust assay reagents and a simple, homogeneous workflow amenable to automation and batch plate processing are important. In all cases, the use of assay reagents with good sensitivity and high specificity for the cytokine of interest is critical.”

Researchers should also assess whether their study goals extend beyond bulk cytokine measurements to include context-specific information, such as the analysis of relevant cell populations. Spectral flow cytometry can be ideal when there is a need to both multiplex and characterize the cytokine-producing cells at the single cell level, especially in cases where sample amount is limited, notes Maria Jaimes, VP of Scientific Commercialization at Cytek Biosciences. “With conventional cytometry the ability to multiplex is limited and to obtain readouts from multiple cytokines, the sample must often be split to stain separately for different cytokines. Using spectral flow cytometry, many readouts (40 or more) can be detected simultaneously with high sensitivity, allowing for the analysis of samples from pediatric patients or other samples with limited volume.”

Managing variability

Assay variability and cross-study comparability remain persistent challenges in cytokine measurement, particularly in clinical settings. Because results and cutoff values are often assay-specific, they are rarely transferable across different platforms or laboratories. Achieving reproducible cytokine quantification therefore requires careful attention to assay sensitivity, sample integrity, and consistency in experimental workflows.

“Researchers often struggle with the variability and sensitivity of cytokine measurements—especially when working with low-abundance analytes or complex biological samples like plasma or serum. Use consistent sample types and preparation methods to ensure data comparability across studies. Validate controls early, and invest time in assay optimization upfront—it saves significant time, cost, and interpretation challenges downstream,” advises Vanitha Margan, Global Product Manager of Immunoassays at Bio-Rad.

Unsurprisingly, integrating automation into cytokine detection workflows not only improves throughput but also helps minimize variability introduced by manual processing. “Automation, pre-optimized multiplex panels, and ready-to-use reagents can significantly reduce hands-on time without compromising performance,” adds Margan. “Platforms that combine multiplexing with minimal manual intervention allow researchers to generate more data per run while ensuring accuracy and reproducibility across different sample types and studies.”

Optimizing cytokine assay workflows

Generally, assay workflows with fewer steps and shorter incubation times tend to be more desirable to users. A faster, streamlined preparation protocol not only improves efficiency but also minimizes opportunities for cytokine degradation. This is an important consideration given their inherently short half-lives, which can range from minutes to a few hours depending on the cytokine and nature of the sample matrix.

“The optimal solution for many is a simple add-and-read format that requires minimal reagent preparation, no transfer or wash steps, and excellent assay performance, including a broad linear range that minimizes the need for sample dilution,” comments Lazar at Promega. “Several homogeneous cytokine assay formats are available that rely upon one form or another of proximity-based assay chemistry, including HTRF, alphaLISA, and Lumit^® assays. Of these, only the Lumit^® cytokine assays are optimized for compatibility with direct addition to cell culture wells.”

Maintaining assay integrity also benefits from recognizing where flexibility can improve efficiency or useability. Even small procedural adjustments can make cytokine assays more manageable in routine laboratory settings. “In my experience, it is vitally important to have a robust assay protocol that clearly identifies critical steps that cannot be modified, but also allows for some flexibility in the execution. For example, when performing intracellular cytokine staining for flow cytometry, the ability to do overnight staining makes the workflow across days more user friendly,” comments Jaimes at Cytek. “Another example to streamline part of the process is to use temperature adjustable water baths when cells require stimulation at 37ºC for extended periods of time.” 

As cytokine detection technologies continue to evolve, success ultimately depends on thoughtful assay design, rigorous validation, and awareness of each method’s limitations. Keeping in mind strict, yet efficient workflows and emerging multiplex platforms, researchers can generate more reliable and clinically meaningful insights into the complex biology of cytokine signaling.

References

Biery DN, Turicek DP, Diorio C, Schroeder BA, Shah NN. Need for standardization of cytokine profiling in CAR T cell therapy. Mol Ther. 2024;32(9):2979-2983. doi:10.1016/j.ymthe.2024.03.030

Knight V, Sepiashvili L. Cytokine testing and challenges for diagnostic and clinical monitoring use. J Allergy Clin Immunol. 2025;155(2):410-413. doi:10.1016/j.jaci.2024.11.025

Mason E. Cytokine Detection Methods. Biocompare. Published December 17, 2024. Accessed October 2025.