Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the strain of coronavirus that causes coronavirus disease 2019 (COVID-19), the respiratory illness responsible for the COVID-19 pandemic. Antibodies produced from an immune response against SARS-CoV-2 are used to analyze prior exposure to the virus. The present invention provides methods for detecting antibodies in response to SARS-CoV-2 infection in a single multiplex immunoassay.

Provided herein are red blood cell control compositions comprising one or more populations of lysable hydrogel particles having an impedance that is substantially similar to the impedance of a human red blood cell of average diameter; and a population of hemoglobin molecules or a population of dye molecules that have substantially similar absorbance as hemoglobin; wherein (i) and/or (ii) are present in an amount that corresponds to a normal blood sample or disease state, or (i) and (ii) are present at a ratio that corresponds to a normal blood sample or disease state.

Methods and reference compositions for quantifying protein using tagged standards. In an exemplary method, a reference composition and a protein may be electrophoresed in respective lanes of a gel. The reference composition may include quantitation standards of different size and each including a tag present at a different concentration. The quantitation standards and the protein may be transferred from the gel to a solid support to create a blot. Luminescence may be detected from the blot to obtain respective luminescence values separately representing an abundance of the tag of each quantitation standard and an abundance of the protein. A quantity of the protein may be determined using the respective luminescence values.

A method of producing a solution containing hemoglobin A2 and a method of producing a hemoglobin precision control substance, the methods including contacting a solution containing hemoglobin and having a pH of from 7.8 to 9.5 with an anion exchanger, are provided.

The present invention relates to a standard material composition for verifying a bio-analysis equipment, comprising quantum dot-containing nanoparticles. Through a standard strip and/or a standard tray, which are made of the standard material composition, the present invention may increase the analysis accuracy of a bio-analysis equipment.

Provided herein are red blood cell control compositions containing one or more populations of lysable hydrogel particles having an impedance that is substantially similar to the impedance of a human red blood cell of average diameter; and a population of hemoglobin molecules or a population of dye molecules that have substantially similar absorbance as hemoglobin; wherein (i) and/or (ii) are present in an amount that corresponds to a normal blood sample or disease state, or (i) and (ii) are present at a ratio that corresponds to a normal blood sample or disease state.

Provided herein are red blood cell control compositions comprising one or more populations of lysable hydrogel particles having an impedance that is substantially similar to the impedance of a human red blood cell of average diameter; and a population of hemoglobin molecules or a population of dye molecules that have substantially similar absorbance as hemoglobin; wherein (i) and/or (ii) are present in an amount that corresponds to a normal blood sample or disease state, or (i) and (ii) are present at a ratio that corresponds to a normal blood sample or disease state.