5 Essentials of Diagnostic Assay Development: Enhancing Precision with Advanced Dispensing Technology

Infectious diseases, oncology, and genetic testing are driving a growing demand for reliable, high-performing diagnostic assays. As these fields evolve, assay developers must achieve scientific rigor and stringent regulatory compliance. From early-stage research to clinical deployment, precision and consistency are essential for diagnostic assay development and are made possible by technological advances in dispensing. This blog explores five essentials for modern assay development—sensitivity, specificity, miniaturization, reproducibility, and automation—highlighting how advanced technologies empower researchers to meet scientific and regulatory demands.

1. Sensitivity: Capturing the Lowest Detectable Signal

Sensitivity refers to the lowest concentration of analyte that can be consistently detected against the background signal of a given assay. High sensitivity is crucial for detecting low abundances of different target molecules, whether it’s plasma proteins in a biomarker study or a qPCR-based workflow looking for low-abundance DNA variants^1,2.

High sensitivity helps to avoid false negatives in which a test sample is incorrectly assumed to be devoid of the target analyte. This is an important factor in research but is crucial in clinical contexts where test results help doctors direct treatment plans³.

Assays optimized for high sensitivity demand precise handling and accurate dispensing of tiny volumes. The I.DOT from DISPENDIX provides nanoliter-scale dispensing, enabling the scaling down of high-sensitivity assays (Fig. 1).

Figure 1. The I.DOT non-contact liquid dispenser dispenses down to 4 nL with 0.1 nanoliter resolution to allow researchers to make the most of high-sensitivity assays.

2. Specificity: Eliminating Background Noise

Cross-reactivity and false positives can be just as problematic for researchers—and potentially harmful to patients—as false negatives⁴. Specificity refers to an assay’s ability to correctly identify the target analyte without reacting to non-target molecules, which includes maintaining a high target-to-background ratio. Achieving high and consistent specificity depends on the precise dispensing of solutions during assay development. Accurate and automated dispensing improves signal-to-background ratios by ensuring uniform reagent concentrations, precise volume dispensing, and consistent application to test “spots⁵.”

Inaccurate dispensing can introduce contaminants or cause cross-contamination of reagents during assay development, which can harm specificity. Non-contact dispensing methods, like those used by the I.DOT non-contact liquid dispenser, help eliminate these risks and enhance assay reliability.

3. Miniaturization: Reduce Cost, Boost Capacity

The reagents and materials used for assay development can be expensive. In particular, high-quality monoclonal primary antibodies can be difficult to source and are often some of the most costly reagents in an ELISA workflow⁶. Moreover, test samples are often limited and difficult to obtain in both research and clinical settings, making efficient use of samples and reagents all the more critical.

Considering these factors, the ability to accurately dispense very small volumes enables researchers and assay developers to conserve expensive reagents by up to 50%, reduce costs, and minimize the risk of errors⁷. Miniaturizing assays also helps preserve valuable samples, leaving more material available for future or repeated analyses.

Lastly, scaling down means more analytes or samples can be assessed in parallel, increasing throughput and data generation without increasing reagent consumption.

4. Reproducibility: Consistency is King in Diagnostics

Assay validation and reproducibility can be negatively impacted by inter-batch and inter-operator variability⁵. This is because dispensing tiny volumes can be incredibly challenging to perform consistently across long time scales and when different individuals use manual dispensing (Fig. 2)⁷. Reproducibility is essential for maintaining long-term assay performance and usability, as it ensures consistent accuracy in individual tests, reliable data over time, and continued safety for end users.

Figure 2. Even when leveraging multichannel pipettes, researchers are vulnerable to introducing assay variability and cannot achieve the throughput of automated systems like the I.DOT non-contact dispenser. (Source)

Advanced dispensing systems like the I.DOT from DISPENDIX automate liquid handling processes to eliminate operator-related variability in assay development. By allowing precise protocols to be programmed and consistently executed over time and in various locations, these instruments help ensure uniform assay performance, enhance reproducibility, and support reliable assay production across users and laboratories.

5. Automation: From Lab Bench to Scalable, Compliant Workflows

Automated platforms not only ensure accurate and consistent dispensing but also allow research and assay production teams to achieve and maintain compliance with global regulatory bodies. 

The In Vitro Diagnostic Regulation (IVDR) and Clinical Laboratory Improvement Amendments (CLIA) ensure diagnostic assays are clinically validated, accurate, and compliant with strict quality standards in the EU and U.S., respectively^8,9. Regarding data security, the FDA’s 21 CFR Part 11 mandates secure, auditable electronic records, supporting compliant assay development and data integrity¹⁰.

Automation helps to provide robust documentation, providing audit trails and integrating barcoding measures to track samples and reagents throughout the workflow, ensuring full traceability. Together, these automated features streamline compliance, enhance reproducibility, and accelerate time to market for diagnostic assays.

Conclusion

In summary, the five essentials—sensitivity, specificity, miniaturization, reproducibility, and automation—are crucial for reliable diagnostic assay development. Together, they contribute to more accurate, efficient, and scalable workflows that meet both scientific and regulatory demands. DISPENDIX’s I.DOT instrument empowers researchers and developers by enabling precise, non-contact, nanoliter-scale dispensing that supports every one of these pillars. DISPENDIX plays a key role in advancing scalable, compliant, and impactful diagnostic solutions, from reducing reagent use to enhancing reproducibility and ensuring regulatory compliance.

Download the I.DOT brochure to discover how automated dispensing can help transform your assay development workflows!

References

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2. Chen S, Huang V, Xu X, et al. Widespread and Functional RNA Circularization in Localized Prostate Cancer. Cell. 2019;176(4):831-843.e22. doi:10.1016/j.cell.2019.01.025
3. Monaghan TF, Rahman SN, Agudelo CW, et al. Foundational Statistical Principles in Medical Research: Sensitivity, Specificity, Positive Predictive Value, and Negative Predictive Value. Medicina (Kaunas). 2021;57(5):503. doi:10.3390/medicina57050503
4. Arevalo-Rodriguez I, Buitrago-Garcia D, Simancas-Racines D, et al. False-negative results of initial RT-PCR assays for COVID-19: A systematic review. PLoS One. 2020;15(12):e0242958. doi:10.1371/journal.pone.0242958
5. Luo Y, Pehrsson M, Langholm L, Karsdal M, Bay-Jensen AC, Sun S. Lot-to-Lot Variance in Immunoassays-Causes, Consequences, and Solutions. Diagnostics (Basel). 2023;13(11):1835. doi:10.3390/diagnostics13111835
6. Weller MG. Quality Issues of Research Antibodies. Anal Chem Insights. 2016;11:21-27. doi:10.4137/ACI.S31614
7. Holland I, Davies JA. Automation in the Life Science Research Laboratory. Front Bioeng Biotechnol. 2020;8(571777). doi:10.3389/fbioe.2020.571777
8. Revision of the In Vitro Diagnostic Devices Regulation. European Commission - European Commission. Accessed April 8, 2025. https://ec.europa.eu/commission/presscorner/detail/en/ip_24_346
9. CDC. Clinical Laboratory Improvement Amendments. Clinical Laboratory Improvement Amendments (CLIA). December 17, 2024. Accessed April 8, 2025. https://www.cdc.gov/clia/php/about/index.html
10. Commissioner O of the. Part 11, Electronic Records; Electronic Signatures - Scope and Application. January 10, 2024. Accessed October 30, 2024. https://www.fda.gov/regulatory-information/search-fda-guidance-documents/part-11-electronic-records-electronic-signatures-scope-and-application