Day: September 30, 2025

Why cross-kit commutability matters for FAP ELISA Quantifying fibroblast activation protein (FAP; a serine endopeptidase with prolyl-specific activity) consistently across platforms is challenging because calibrators, capture/detection antibody pairs, assay buffers, and curve-fitting models differ by kit. “Commutability” asks whether a material shows the same numerical relationship between different measurement procedures as authentic clinical/research samples. In…

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Adsorption Controls (the biggest hidden loss)  Container material Polypropylene (PP, low-bind recommended): Lowest non-specific binding among common lab plastics; preferred for storage and aliquots. Polystyrene (PS): High protein adsorption; acceptable for short manipulations only if carrier/detergent is present. Avoid for long storage. Glass (borosilicate): Can be good with siliconization; uncoated glass may denature/adsorb proteins at…

Read More “Formulation & Stability Playbook for rhGM-CSF in Cell-Culture Workflows” »

Acceptable Matrices & Why They Matter  Serum, Plasma (EDTA/Heparin/Citrate), Whole Blood Serum. Coagulated blood; absence of fibrin can reduce matrix interference in some immunoassays. See fundamentals of specimen types in clinical chemistry curricula at UCSF, UMich, and sample processing primers from CDC and NIH. Plasma. Anticoagulated; anticoagulant choice affects ionic strength and protein interactions. EDTA…

Read More “Pre-Analytical Discipline for Field Reliability: Volumes, Dilutions, and Matrix Choice per IFU” »

Context and problem definition Fluorometric RNA High Sensitivity (HS) assays are widely used to quantify low-abundance RNA. Despite selectivity, dsDNA contributes measurable fluorescence, so residual gDNA in RNA preps leads to overestimation of “RNA”. This article provides a complete operating procedure to (i) profile dye selectivity in practice, (ii) design paired measurements (RNA HS vs…

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Why it matters. Most water-soluble B-vitamins—B1, B2, B3, B5, B6, B7, B9, B12—are low-molecular-weight analytes (<1 kDa) that lack two distinct antibody-accessible epitopes. As a result, competitive immunoassay formats are typically required, with success hinging on hapten design, choice of tracer/coating strategy, stringent cross-reactivity profiling across vitamers and degradants, and calibrators that are traceable and…

Read More “Designing Competitive ELISAs for Small-Molecule B-Vitamins: From Hapten–Carrier Conjugates to Commutable Calibrators” »