Proprietary two-factor authentication mechanism
With traditional proximity extension assays, transient hybridization of antibody probes generates non-specific noise.
SPEAR employs a unique two-factor authentication mechanism, requiring antibodies to remain target-bound for an extended period of time to generate an amplifiable signal, leading to extremely low background.
A homogeneous assay without wash steps
1
Bind
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Incubate 1 µL of diluted sample with proprietary SPEAR probes, allowing sufficient time for antibodies to bind their target.
2
React
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Add reaction mix to the well without any washing. Two-factor authentication occurs, the key to achieving exceptional sensitivity and specificity.
3
Amplify
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After the reaction is complete, qPCR mix is added to the well without any washing. After amplification, target-specific signal is quantified from the qPCR results.
Proven sensitivity advantage
SPEAR delivers superior sensitivity compared to the most advanced heterogeneous platforms, including digital ELISA. Unlike wash-based assays, SPEAR’s performance is less constrained by antibody affinity, achieving consistently high sensitivity across a wide range of biomarkers—even with lower-affinity antibodies.
As shown in the example on the right, with low-affinity antibodies, digital ELISA improved sensitivity by only ~1 log for Analyte 1. In contrast, SPEAR consistently reached attomolar detection, delivering an over 5-log improvement versus conventional ELISA.
Parallel plexing with small volumes
SPEAR enables multiple biomarkers to be run in parallel, each using 1 µL of diluted sample, delivering unparalleled sensitivity, specificity, precision, and robustness with the convenience of a multiplex assay.
Targets incapable of traditional multiplexing can be measured in parallel from a single sample, in the same plate, and analyzed in the same qPCR run.
Boundless degrees of freedom
Our homogeneous assay format eliminates solid surface immobilization and the need for error-prone wash steps, offering multiple advantages that lead to robust protein quantification.
Increased specificity
Optimal orientation for epitope-specific interaction allowed in homogeneous solution.
Improved kinetics
Rapid diffusion leads to shorter incubation time for Ag-Ab binding.
High consistency
Three-step wash-free workflow minimizes error-prone processes.
Seamless automation
Streamlined workflow easily integrates with automation solutions.
Robust ultra-sensitivity
Absence of wash step eases the criteria for Ab affinity.
Greater binding efficiency
Ag–Ab binding maximized by lack of steric hindrance to solid surface.
Connect with Spear Bio
To learn how our ultra-sensitive biomarker assay technology can aid your investigation, let’s talk.
FAQs – SPEAR Biomarker Assays
SPEAR UltraDetect™ biomarker assays have 6 logs or more of dynamic range to work with, making them adaptable to most, if not all, biomarker assay applications. We optimize the assay calibration range to each specific biomarker and their intended use.
SPEAR UltraDetect™ biomarker assays work with plasma, serum, CSF, dried blood or plasma spots, nasal swabs, saliva, and others, depending on the specific biomarker assay application.
All SPEAR UltraDetect™ biomarker assay products are manufactured in an ISO 13485 facility following our QMS procedures. We are actively working to expand our ISO scope as we broaden the research applications of our biomarker assays. For more information on our ISO certification, please review our certificate or contact us.
Yes. We have demonstrated excellent concordance between the SPEAR UltraDetect™ Neurofilament light chain biomarker assay to the Quanterix and MSD biomarker assays for NfL. The data for SPEAR biomarker assays vs Quanterix and MSD can be reviewed in app note or on our poster from AAIC 2024 We also have demonstrated concordance for our SPEAR UltraDetect™ pTau 217 biomarker assay to the Quanterix ALZpath biomarker assay in this published app note, where you will see that SPEAR has an edge on the clinical application.
Yes. There is a preprint in review using our NAB-Sure™ biomarker assay and the manuscript describing SPEAR biomarker assay technology will be published soon.
Be sure to subscribe to our mailing list, to receive a notification on the completed manuscript, plus updates on any forthcoming publications, and more!
