Comparison of potential higher order reference methods for total haemoglobin quantification—an interlaboratory study

Abstract

The total haemoglobin (Hb) concentration in blood is one of the most frequently measured analytes in clinical medicine because of its significance for evaluating the health state of a human. The spectrophotometric cyanmethaemoglobin (HiCN) method is the internationally accepted conventional reference method to determine this biomarker. It is frequently used in clinical routine diagnostics but is not traceable to the International System of Units and thus does not meet highest metrological demands. A further critical issue is the toxicity of the necessary potassium cyanide. Different methods to solve these problems are reported here. They all were validated against the HiCN method in an interlaboratory comparison by measuring the total Hb concentration present in the certified reference material JCCRM 912-2M. Methods considered were the spectrophotometric alkaline haematin detergent (AHD) method as well as several isotope dilution (ID)-based approaches. The latter include inductively coupled plasma mass spectrometry (ICP-MS), species-specific (SS) ICP-MS, organic MS and Raman spectrometry. Graphical abstract ᅟ.

All-in-one superparamagnetic and SERS-active niosomes for dual-targeted in vitro detection of breast cancer cells

“…Since we chose TNB as the Raman-active compound, the hybrid niosomes possess the inherent capability to establish a quantification principle using the isotope dilution (ID) technique, which has already been used in combination with SERS. [93][94][95] Therefore, apart from ex vivo quantification procedures to investigate biomarker concentrations in human fluids (blood, cerebrospinal fluid etc. ), an in vivo ID-SERS approach could aim to establish a correlation between the isotope-based Raman-shift and 2D-SERS measurements to draw conclusions about the volume and shape of the tumor.…”

All-in-one Superparamagnetic and SERS-active Niosomes for Dual-targeted in Vitro Detection of Breast Cancer Cells

“…Furthermore, the niosome shell induced the formation of interparticle hot spots and shielded the AuNPs To validate SERS-based imaging and monitoring of tumorous tissues for ex vivo diagnosis or even for staining tumor cells in vivo using the presented hybrid niosomes, extensive and elaborate in vivo experiments are mandatory. Since we chose TNB as the Raman-active compound, the hybrid niosomes possess the inherent capability to establish a quanti cation principle using the isotope dilution (ID) technique, which has already been used in combination with SERS [78][79][80]. Therefore, apart from ex vivo quanti cation procedures to investigate biomarker concentrations in human uids (blood, cerebrospinal uid etc.…”

Step‐by‐step monitoring of a magnetic and SERS‐active immunosensor assembly for purification and detection of tau protein

“…The simplified preparation concept for a controlled formation for a SERS‐active immunosensor greatly improves the applicability of this approach and allows a larger scale implementation. Furthermore, a quantification principle will be established utilizing the isotope dilution (ID) technique, which is mostly used in mass spectrometry, but which has also been shown to work excellently when combined with Raman spectroscopy . Besides the advantages of having molecular specificity, accuracy and a high sensitivity during quantification, an ID‐SERS approach also could provide SI‐traceability of the measurement results when combined with well‐characterized reference materials.…”

“…For this purpose, so‐called reference measurement methods must be provided, which are ideally connected directly to the international system of units (SI) . It has already been demonstrated that SERS‐based methods are basically suitable for realizing the required SI‐traceability . However, the establishment of a reference measurement method to quantify extremely low concentrations of large biomarker molecules such as tau protein is still challenging and time consuming.…”