Description Enzyme Immunoassay for the quantitative determination of Beta 2-microglobulin (B2M) in human serum, plasma, and urine samples. Quality controls are included with the kit. Developed and manufactured in Europe by PromedeusLab. Summary Urinary excretion of Beta 2-microglobulin (beta 2M) is a widely used test of renal proximal tubular function (1). Proximal tubular dysfunction leads to an increased urinary concentration (2). The serum level of beta 2-microglobulin is determined by the glomerular filtration rate and the rate of synthesis. Increased production, with raised serum levels, is sometimes observed in malignancy-mainly at an advanced state (2). A strong correlation between lupus nephritis (LN), disease activity, and serum beta 2-microglobulin (b2MG) was observed. Serum b2MG level could potentially be a valuable predictor for LN, clinical disease activity, and damage score (3). Other Names β2 microglobulin (B2M), B2MG, beta-2-microglobulin, Β2 microglobulin, UniProtKB# P61769 Principle of Method The microtiter plate is coated with the antibody specifically binding the Beta 2-microglobulin. The human serum, plasma or urine is incubated in the plate with the capture antibody. The specimen is washed out and the specifically bound protein is incubated with HRP-labelled detection antibody. Unbound reagent is then washed out. Horseradish peroxidase (HRP) bound in the complex reacts with the chromogenic substrate (TMB) creating the blue colour. The reaction is stopped by addition of STOP solution (H2SO4). The absorbance values are measured at 450 nm (optionally 450/630 nm) and are proportional to the concentration of the Beta 2-microglobulin the specimen. The concentration of Beta 2-miroglobulin in unknown samples is determined from the calibration curve which is created by plotting the absorbance values against the standard concentration values. Sample Types Serum, Plasma, Urine Typical Standard Curve Assay Range: 1.25 ng/mL - 40 ng/mL Sensitivity The limit of detection, defined as a concentration of human Beta 2-microglobulin giving absorbance higher than absorbance of blank +3 standard deviations, is better than 0.42 ng/mL of sample. Precision Intra-Assay Test sample Mean (ng/mL) SD CV 1 1049 49 5% 2 2178 131 6% Inter-Assay (Run-to-Run) Test sample Mean (ng/mL) SD CV 1 1191 115 10% 2 1469 88 6% Accuracy Dilution Linearity: Test sample Dilution Measured Concentration (ng/mL) Expected Concentration (ng/mL) Yield 1 2195 - - 1 2x 1048 1097 96% 1 4x 495 549 90% 1 8x 235 274 86% 2 1295 - - 2 2x 586 647 91% 2 4x 324 324 100% 2 8x 138 162 85% Spiking Recovery: Test sample Spike (ng/mL) Measured Concentration (ng/mL) Expected Concentration (ng/mL) Yield 1 - 1059 - - 1 3000 4186 4059 103% 1 1500 2937 2559 115% 1 750 1934 1809 107% Storage The kit must be stored at 2–8 °C. The opened components can be stored for one week at 2–8 °C. Usage This assay is for in vitro research use only and is not for use in diagnostic procedures. Resources Product Datasheet (PDS) Summary References Davey PG, Gosling P. beta 2-Microglobulin instability in pathological urine. Clin Chem. 1982 Jun;28(6):1330-3. PMID: 6176371. Karlsson FA, Wibell L, Evrin PE. beta 2-Microglobulin in clinical medicine. Scand J Clin Lab Invest Suppl. 1980;154:27-37. PMID: 6163193. Gamal DM, Badr FM, Taha SIAEF, Moustafa NM, Teama MAEM. Serum beta-2 microglobulin as a predictor of nephritis, disease activity, and damage score in systemic lupus erythematosus: a cross-sectional study. Rheumatol Int. 2022 Oct 7. doi: 10.1007/s00296-022-05221-1. Epub ahead of print. PMID: 36205758. Ilex Life Sciences LLC is an authorized distributor of PromedeusLab.
