A method for determining the amount of specific analyte of a sample which may show interferences by photometric assays, wherein the analyte is quantified from the change in the optical signal of the reaction mixture after the interaction of the analyte with analyte specific reagents. Multiple calibration curves are generated for multiple wavelengths for the specific analyte. An interference test is performed simultaneously to the determination of the specific analyte, for quantifying the amount of interfering substances present in the sample. The amount of each interfering substances is compared to predetermined cut-off values. The optical signal for the specific analyte is measured in the reaction mixture at multiple wavelengths over the complete reaction time, and a calibration curve is selected depending on the interfering substances. The amount of specific analyte is quantified by comparison with the selected calibration curve for the chosen wavelengths.

The present invention provides a method for detection of a basic peptide by mixing a sample suspected to contain the basic peptide and a reagent containing denatured albumin and detecting turbidness due to a complex of the basic peptide and denatured albumin.

Disclosed herein are methods of protein quantification and normalization using haloalkylated tryptophan fluorescence. Complex protein samples, i.e., samples that each contain 1,000 or more distinct proteins, from diverse sources that do not have common protein profiles are treated with a halo-substituted organic compound (i.e. haloalkane) that reacts with tryptophan residues to form fluorescent products. Irradiation of the samples with ultraviolet light and the detection and quantification of the resultant fluorescent emissions from all proteins in each sample are then used to obtain comparative values for total protein content among the various samples. The values thus obtained are found to be valid indications of comparative total protein content, despite the fact that the tryptophan levels vary widely among the various proteins in any single sample and the samples, due to the diversity of their origins, tend to differ among themselves in the identities and relative amounts of the proteins that they contain. Protein samples are also normalized to correct for differences in sample dilution, sample loading, and protein transfer inconsistencies, by using stain-free detection of total protein in each of the samples, or detection of subsamples within each sample.

The present invention provides biomarkers of oxidative stress in subjects with retinitis pigmentosa, age-related macular degeneration, diabetic retinopathy, Fuchs' dystrophy, diabetic macular edema (DME), geographic atrophy, Stargardt's disease, or retinal vein occlusion (RVO), and their use in identifying subjects in need of treatment and methods for staging the severity of the disease.

A method of quantifying target molecules comprising the steps of: binding target molecules to a surface, wherein the target molecules are presented for a quantification assay; cleaning the target molecules of contaminating reagents, wherein the target molecules remain bound to the surface; directly quantifying the target molecules, wherein the target molecules remain bound to the surface, wherein direct quantification of the target molecules is performed by measurement of intrinsic fluorescence of the target molecules.

This present disclosure provides methods and compositions that can be used to quantify cfDNA in biofluids using a hybridization approach.

Systems and methods are provided for sample processing. A device may be provided, capable of receiving the sample, and performing one or more of a sample preparation, sample assay, and detection step. The device may be capable of performing multiple assays. The device may comprise one or more modules that may be capable of performing one or more of a sample preparation, sample assay, and detection step. The device may be capable of performing the steps using a small volume of sample.

In a method for analyzing cells, a sample fluid having a suspending medium and cells is fed to a microfluidic device having at least one cell processing unit having a trapping region, a reaction unit, and an outlet arrangement. The trapping region is delimited by at least an input valve and a sieve valve, in particular a v-type valve that is capable of retaining the cells while letting fluids pass. The method includes trapping cells in the trapping region, subsequently establishing a flow of a reaction fluid through the trapping region while the sieve valve assumes the open state, such that the reaction fluid transfers the trapped cells from the trapping region into the reaction unit, decomposing the transferred cells into cell fragments through a decomposition process, collecting the cell fragments in the outlet arrangement, and analyzing the cell fragments.

A multiplex proteome quantification method based on isobaric dimethyl labeling, which implements dimethyl labeling of peptide N-terminal in an acidic condition and C-terminal in an alkaline condition one after another by means of a property that a dimethylation reaction has different rates on an amino group at the peptide N-terminal and an amino group on a Lysine side chain at the peptide C-terminal in the acidic condition. Multiplex labeling of peptide samples is implemented by means of the organic combination of various isotope forms of a dimethyl labeling reagents. The mass-to-charge ratios in MS1 of peptides after multiplex labeling are completely the same, the mass-to-charge ratios of the fragment ions in MS2 are different, and multiplex quantitative analyses are carried out by extracting the intensity values of corresponding fragment ions in the MS2. The method has advantages of high quantitative accuracy, high precision, wide dynamic range and high-throughput of quantitative analysis, which can implement the simultaneous quantitative analysis of six protein samples, thereby greatly improving the throughput of the quantitative analysis of proteins and saving the analysis time.

A method for determining the amount of a specific analyte by photometric assays, wherein the specific analyte in a sample reacts with an analyte specific reaction partner in a reaction mixture. At least two calibration curves are generated, the first calibration curve recorded at a first wavelength is optimized for low concentrations of the specific analyte thereby maximizing the lower detection limit and, the second calibration curve recorded at a second wavelength is optimized for high concentrations of the specific analyte thereby maximizing the upper detection limit. The optimized lower detection limit and the optimized upper detection limit results in an extended dynamic range.