Alzheimer’s disease diagnostics are changing rapidly. Amyloid-targeting therapies have reached clinical practice,1,2 and blood-based tests are becoming part of the diagnostic landscape.3 These developments are increasing the demands placed on biomarker assays, including the ability to reliably measure low concentrations of clinically relevant analytes such as amyloid beta (Aβ).
Alzheimer’s disease is the most common cause of dementia, accounting for an estimated 60-80% of cases.4 Amyloid beta is one of its earliest indicators, detectable years before major cognitive symptoms appear.5 Aβ1-40 and Aβ1-42 are among the most commonly measured forms of amyloid beta. The Aβ42/40 ratio can improve interpretation by accounting for interindividual differences in overall amyloid beta production.6
Please visit the below link if you'd like to read more on:
How IVD Enables Earlier and More Accurate Alzheimer’s Disease Diagnosis
The clinical role of biomarker testing is also evolving. Confirmation of amyloid pathology has become increasingly relevant as amyloid-targeting therapies enter clinical use.1,2 At the same time, blood-based biomarkers are creating less invasive approaches to the assessment of Alzheimer’s disease pathology.3,7 In May 2025, the U.S. FDA cleared the first blood test to aid in diagnosing Alzheimer’s disease, based on the p-tau217/Aβ1-42 ratio,3 and in July 2025 the Alzheimer’s Association issued its first clinical practice guideline with performance thresholds for blood-based biomarker tests.9 These developments create new analytical demands for biomarker assay development.
Medix Biochemica hosted a Webinar: Soluble Biomarkers for Alzheimer's Disease
The relevant question for assay developers is not simply whether an antibody recognizes amyloid beta, but whether an antibody pair can provide sufficient signal as analyte concentrations decrease. As amyloid pathology increases, cerebrospinal fluid (CSF) Aβ42 concentrations decrease,8 making reliable measurement at lower concentrations particularly important. In a sandwich immunoassay design, C-terminal antibodies can provide specificity for Aβ1-40 or Aβ1-42, while an N-terminal antibody can serve as the detection antibody for both forms.
Medix Biochemica’s R13622 and R13625 are N-terminal monoclonal antibodies recognizing both Aβ1-40 and Aβ1-42. They can be used as detection antibodies with the corresponding C-terminal capture antibodies: R13611 for Aβ1-40 and R13602 for Aβ1-42.
In an unoptimized fluorescence immunoassay (FIA) test format, the recommended antibody pairs demonstrated sensitive detection of Aβ1-40 and Aβ1-42, with detection extending into the low pg/mL range.10
In a patient-sample evaluation for Aβ1-42, R13602 paired with R13622 or R13625 showed strong correlation with Fujirebio Lumipulse measurements in the tested CSF samples, with R² values above 0.99.10
The recommended pairs have been evaluated for FIA and chemiluminescent immunoassay (CLIA) development and are applicable to other immunoassay formats.
These results provide supporting performance data for assay developers evaluating the antibody pairs in sensitive Aβ1-40 and Aβ1-42 immunoassays. Performance should be established in the intended assay format and sample matrix.
Beyond amyloid beta, the Medix Biochemica neurology portfolio includes tau biomarkers, GFAP, NfL and other biomarkers relevant to neurodegenerative disease research and diagnostics, together with human biospecimens for assay development and evaluation. The portfolio continues to expand, with additional products currently in development.
Read more: Prevalence and Growth of Neurological Conditions Worldwide
Ready to optimize your Alzheimer’s biomarker assay? Get in touch with our scientific team to discuss your development requirements and evaluate our antibody pairs.
Explore the Amyloid Beta antibodies and the wider neurology portfolio.
References