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Clin Lab ; 70(2)2024 Feb 01.
Article En | MEDLINE | ID: mdl-38345970

BACKGROUND: Serum Protein Electrophoresis (SPE) is crucial for the diagnosis and follow-up of monoclonal gammopathy (MG), as it helps to separate and identify these paraproteins. Currently, Pakistan lacks standardized guidelines for SPE reporting and analytical performance. This survey aims to analyze reporting variations from Consultant Chemical Pathologists in Pakistani laboratories. METHODS: This cross-sectional survey was conducted by the section of Chemical Pathology, Department of Pathology and Laboratory Medicine, at Aga Khan University Hospital, Karachi. A previously validated and published tool was used with some modifications to assess analytical techniques, reporting patterns, and interpretations provided with SPE by different laboratories. Frequency and percentages were calculated for each response and descriptive results were also evaluated. Differences between laboratories were also assessed qualitatively. RESULTS: Out of the eight laboratories contacted, seven participated in the survey, yielding a response rate of 87.5%. Immunofixation Electrophoresis (IFE) was used by all labs for serum immunotyping. All labs reported a new small abnormal band in patients with no known monoclonal gammopathy or with a known M-protein. Variations were found in terminologies used to label paraprotein, terminologies used to report normal and pathological SPE patterns, electrophoretic technique, methods for quantifying paraprotein in the gamma region on SPE and for albumin quantification. Similarly, the number of decimal places reported, reporting of multiple monoclonal proteins and small paraprotein in the beta region or monoclonal proteins less than 1 g/L, approach for screening, number of fractions reported in gamma region and reporting of interferences were also not standardized and var-iations were noticed. CONCLUSIONS: Our survey highlighted variations in practices of SPE reporting. These differences in laboratory practices could result in inconsistent test results, which could adversely affect patient care.

Paraproteinemias , Humans , Pakistan , Cross-Sectional Studies , Electrophoresis , Paraproteinemias/diagnosis , Paraproteins/analysis , Paraproteins/metabolism
Methods Mol Biol ; 2763: 45-50, 2024.
Article En | MEDLINE | ID: mdl-38347398

Studying salivary gland mucins is important for elucidating the pathogenesis of salivary gland diseases, including tumors and xerostomia, and developing diagnostic methods for them. Classic methods for isolating mucins from salivary glands require sacrificing several animals to obtain sufficient quantities of mucin and are time-consuming. Supported molecular matrix electrophoresis (SMME) was used to characterize mucins and their glycans. With this method, mucins can be analyzed within 2 days using less than 100 mg of tissue and without using expensive equipment, such as an ultracentrifuge. This chapter describes a method for preparing mucin solutions for SMME analysis of salivary gland mucins.

Mucins , Submandibular Gland , Animals , Submandibular Gland/chemistry , Salivary Glands , Electrophoresis/methods , Polysaccharides
Methods Mol Biol ; 2763: 79-97, 2024.
Article En | MEDLINE | ID: mdl-38347402

Distinct bands of mucins cannot be banded using a gel electrophoresis based on a molecular sieving effect due to their very large molecular weight and remarkable diversity in glycosylation. In contrast, membrane electrophoresis can separate mucins as round bands. Here, we present an analysis of mucin separation via membrane electrophoresis using a porous polyvinylidene difluoride membrane, which is highly stable against chemical modifications and various organic solvents. The separated mucins can not only be stained with dyes but also with antibodies and lectins, and glycans can be released from the excised bands and analyzed.

Coloring Agents , Mucins , Electrophoresis/methods , Mucins/chemistry , Coloring Agents/chemistry , Lectins , Glycosylation , Electrophoresis, Polyacrylamide Gel
J Chromatogr A ; 1717: 464685, 2024 Feb 22.
Article En | MEDLINE | ID: mdl-38310700

This study contributes to the renewed interest in the study of nonlinear electrophoresis of colloidal particles. In this work the influence of cell shape on electrophoretic migration under the nonlinear regimes of moderate and strong field regimes was assessed. Four types of bacterial and yeast cells (one spherical, three non-spherical) were studied and their electrophoretic mobilities for the moderate and strong electric field magnitude regimes were estimated experimentally. The parameter of sphericity was employed to assess the effect cell shape on the nonlinear electrophoresis migration velocity and corresponding mobility under the two electric field magnitude regimes studied. As particle migration under nonlinear electrophoresis depends on particle size and shape, the results in terms of mobilities of nonlinear electrophoresis were presented as function of cell hydrodynamic diameter and sphericity. The results indicated that the magnitude of the mobilities of nonlinear electrophoresis for cells increase with increasing cell size and increase with increasing deviations from spherical shape, which is indicated by lower sphericity values. The results presented here are the very first assessment of the two types of mobilities of nonlinear electrophoresis of cells as a function of size and shape.

Electricity , Hydrodynamics , Cell Shape , Electrophoresis/methods , Particle Size
Anal Chim Acta ; 1287: 342110, 2024 Jan 25.
Article En | MEDLINE | ID: mdl-38182347

BACKGROUND: Liposomal formulations have traditionally been considered the most therapeutically effective drug delivery systems (DDS). However, their pharmacokinetics study and efficacy assessment are still challenging given size heterogeneity and unknown forms in vivo. The pharmacodynamic evaluation that solely analyzes total drug concentration is unfit for the liposomal formulation study. Hence, it is crucial to develop effective strategies for the separation and analysis of different forms of liposomal formulations in order to contribute to the study of pharmacokinetic profiles associated with both liposome-incorporated and non-liposomal drugs. (84) RESULTS: A laboratory-built circular nonuniform electric field gel electrophoresis (CNEFGE) system was developed in this study for simultaneous separation and analysis of various forms of doxorubicin hydrochloride (DOX•HCl) liposomes. Liposomes were effectively fractionized based on their size and higher concentration in situ in the concentration zone, obtaining liposome recovery >95 % and a 3.04 concentration factor. It was found that the technique could be used to evaluate not only the size distribution of liposomes but also the drug loading capacity related to size. The charge-to-size-based separation mechanism has also allowed the simultaneous separation of liposome-entrapped drugs, protein-bound drugs, and free drugs in various forms, and the technique has been successfully employed in serum. Moreover, the quantification analysis of liposomes incubated with serum for 72 h showed that the proportion of the ratio of DOX•HCl in liposome-entrapped drugs, protein-bound drugs, and free drugs is approximately 97:2:1. (143) SIGNIFICANCE: Using the separation principle of gel electrophoresis and the electrification characteristics of drug carriers, this study developed and implemented an efficient approach for the simultaneous separation and concentration of multiple forms of drug liposomes in vivo. This approach offers a wide range of applications in the pharmacokinetics, efficacy, and safety evaluation of drug carriers and liposomes. (56).

Drug Carriers , Liposomes , Drug Delivery Systems , Doxorubicin , Electrophoresis
Anal Chim Acta ; 1287: 342053, 2024 Jan 25.
Article En | MEDLINE | ID: mdl-38182365

Rapid and specific detection of virulent bacterial strains is a great challenge for food safety regarding large amounts of contaminated samples. Herein, a dual-mode hydrogel array biosensor was constructed to simultaneously rapidly screen and precisely quantitatively detect virulent Escherichia coli O157:H7 (E. coli O157:H7) based on a novel DNA-modified phage probe. First, E. coli O157:H7 was incubated with alginate to form the E. coli O157:H7/hydrogel premix complex. Subsequently, hydrogel formation by cross-linking upon the addition of calcium ions and phages for E. coli O157:H7 modified with a DNA primer (phage-DNA) was added to the alginate hydrogel. The DNA on the complex could trigger rolling circle amplification (RCA) to form a phage probe containing a long-chain DNA skeleton (phage@RCA-DNA). The RCA-DNA was then hybridized with the complementary DNA (cDNA) to form double-stranded DNA fragments (phage@RCA-dsDNA), which could be stained by the SYBR Green dye to emit visual green fluorescence (FL) and determined by a smartphone for rapid screening. Meanwhile, the unreacted cDNA in the supernatant could be quantitatively detected by microfluidic chip electrophoresis (MCE). The signal decrement was also proportional to the bacterial concentration. The detection limit values of E. coli O157:H7 were 50 CFU mL-1 by the FL signal and 6 CFU mL-1 by the MCE signal. The two results could be mutually corrected to decrease the false-positive results. This assay was also employed to detect virulent Salmonella Typhimurium (S. Typhimurium) using the corresponding S. Typhimurium phage@RCA-DNA probe. All these results demonstrated that the universal bioassay was suitable for simultaneous rapid screening and precisely quantitative detection of virulent bacterial strains.

Bacteriophages , Escherichia coli O157 , DNA, Complementary , Hydrogels , Microfluidics , DNA Probes , Alginates , Coloring Agents , Electrophoresis
Anal Chim Acta ; 1289: 342207, 2024 Feb 08.
Article En | MEDLINE | ID: mdl-38245206

Electrophoresis titration chip (ETC) is a versatile tool for onsite and point-of-care quantification analyses because it affords naked-eye detection and a straightforward quantification format. However, it is vulnerable to changes in environmental temperature, which regulates the electrophoretic migration by affecting the ion mobility and the target recognition by influencing the enzyme activity. Therefore, the quantification accuracy of the ETC tests was severely compromised. Rather than using the dry bath or heating/cooling units, we proposed a facile model of dual calibration standards (DCS) to mathematically eliminate the effects of temperature on quantification accuracy. To verify our model, we deployed the ETC device at different temperatures ranging from 5 to 40 °C. We further utilized the DCS-ETC to determine the protein content and uric acid concentration in real samples outside the laboratory. All the experimental results showed that our model significantly stabilized the quantification recovery from 35.31-153.44 % to 99.38-103.44 % for protein titration; the recovery of uric acid titration is also stable at 96.25-106.42 %, suggesting the enhanced robustness of the ETC tests. Therefore, DCS-ETC is a field-deployable test that can offer reliable quantification performance without extra equipment for temperature control. We envision that it is promising to be used for onsite applications, including food safety control and disease diagnostics.

Point-of-Care Systems , Uric Acid , Temperature , Calibration , Electrophoresis , Proteins
Eur Biophys J ; 53(1-2): 1-13, 2024 Feb.
Article En | MEDLINE | ID: mdl-38160206

Gel electrophoresis, a transport technology, is one of the most widely used experimental methods in biochemical and pharmaceutical research and development. Transport technologies are used to determine hydrodynamic or electrophoretic properties of macromolecules. Gel electrophoresis is a zone technology, where a small volume of sample is applied to a large separation gel matrix. In contrast, a seldom-used electrophoresis technology is moving boundary electrophoresis, where the sample is present throughout the separation phase or gel matrix. While the zone method gives peaks of separating macromolecular solutes, the moving boundary method gives a boundary between solute-free and solute-containing phases. We will review electrophoresis as a transport technology of zone and moving boundary methods and describe its principles and applications.

Hydrodynamics , Research Design , Electrophoresis
Rev. esp. enferm. dig ; 115(12): 742-744, Dic. 2023. ilus
Article En | IBECS | ID: ibc-228733

We present a case of a 67-year-old male presenting with severe abdominal pain, laboratory tests revealed IgG levels of 63.5 g/L, IgG4 levels of 63.7 g/L, and negative results for ANCA (Anti-Neutrophil Cytoplasmic Antibodies), Hematuria immunofixation electrophoresis, as well as Cold globulin qualitative test. 18F-FDG PET/CT revealed multiple lesions with increased metabolism in the submaxillary saliva gland, intrahepatic bile ducts, prostate, seminal vesicle glands, and the body of the pancreas. Additionally, a circular cystic-solid lesion with metabolic heterogeneity was observed in the head of the pancreas, accompanied by visible dilatation of the pancreatic duct. The diagnostic imaging suggested IgG4-related disease (IgG4-RD), while pancreatic malignancy could not be definitively ruled out. The patient underwent fine-needle aspiration (FNA) biopsies of lung nodules and the prostate gland, all of which were consistent with the diagnosis of IgG4-RD. Additionally, FNA biopsy of a pancreatic lesion is consistent with the diagnosis of pancreatic ductal adenocarcinoma.(AU)

Humans , Female , Aged , Electrophoresis , Pancreatic Neoplasms , Fluorodeoxyglucose F18 , Positron Emission Tomography Computed Tomography , Immunoglobulin G4-Related Disease
J Avian Med Surg ; 37(3): 266-274, 2023 Nov.
Article En | MEDLINE | ID: mdl-37962319

Plasma electrophoresis is an ancillary diagnostic tool in avian medicine, with agarose gel electrophoresis (AGE) and capillary zone electrophoresis (CZE) being the most common techniques. Frozen samples can be used for quantitative studies or comparative diagnostic purposes, but stability of avian plasma proteins under freezing is poorly described. To evaluate the influence of plasma freezing on electrophoretograms in white storks (Ciconia ciconia), heparin blood was sampled from 30 individuals during annual health examinations. Plasma samples were obtained after centrifugation of fresh samples and divided into aliquots. Both AGE and CZE were performed on fresh aliquots. The remaining aliquots were frozen at -20°C (-4°F) or -180°C (-292°F) and thawed following different protocols: 1 freeze/thaw cycle after 6 months at -20°C; 1, 2, 4, and 7 cycles over 12 months at -20°C; and 1 cycle after 18 months at -180°C. For both techniques, electrophoretic profiles obtained from these thawed aliquots were compared to fresh electrophoretograms. Quantitatively, significant differences (P < 0.05) in most fractions were seen from 6 months postfreezing at -20°C for both techniques. Fewer statistically significant differences were observed after 18 months under cryogenic preservation (-180°C). Qualitatively, AGE provided more repeatable and stable results than CZE over time on samples stored at -20°C, and electrophoretograms were stable after 18 months of cryogenic storage. An electromigration distortion associated with freezing was seen with CZE only. Plasma samples stored in a conventional freezer (-20°C) should not be compared to fresh plasma. For quantitative studies, cryogenic storage should be privileged.

Cold Temperature , Specimen Handling , Animals , Freezing , Temperature , Specimen Handling/veterinary , Electrophoresis/veterinary
Arch Razi Inst ; 78(3): 1077-1085, 2023 Jun.
Article En | MEDLINE | ID: mdl-38028839

Feline infectious peritonitis (FIP) continues to be one of the most researched infectious diseases of cats. The diagnosis of FIP is challenging, and diverse techniques have been developed for its accurate diagnosis. However, they have some limitations. The present study was conducted to investigate the efficacy of specific modulation frequency (SMF), compared to other routine diagnostic methods for detecting feline coronavirus. Blood samples were collected from 30 diseased cats suspected of having FIP based on clinical signs. Electrophoresis, polymerase chain reaction (PCR), and SMF tests were performed for each sample. The sensitivity and specificity of each test, as well as the agreement between the tests and the gold standard (the combination of PCR, electrophoresis, and bioresonance results), were calculated using the Kappa coefficient method. The sensitivity and specificity of electrophoresis, PCR, and SMF for the diagnosis of FIP were 70.6%, 70.6%, 100%, and 100%, 72.7%, 81.8%, respectively. According to the findings of the present study, SMF is effective and safe in FIP diagnosis, which is a challenge in veterinary medicine diagnosis.

Cat Diseases , Coronavirus, Feline , Feline Infectious Peritonitis , Animals , Cats , Feline Infectious Peritonitis/diagnosis , Reverse Transcriptase Polymerase Chain Reaction , Polymerase Chain Reaction/veterinary , Coronavirus, Feline/genetics , Electrophoresis
Anal Chem ; 95(45): 16710-16716, 2023 11 14.
Article En | MEDLINE | ID: mdl-37916500

Extracellular vesicles (EVs) are cell-derived, naturally produced, membrane-bound nanoscale particles that are linked to cell-cell communication and the propagation of diseases. Here, we report the design and testing of in-plane nanofluidic devices for resistive-pulse measurements of EVs derived from bovine milk and human breast cancer cells. The devices were fabricated in plane with three nanopores in series to determine the particle volume and diameter, two pore-to-pore regions to measure the electrophoretic mobility and zeta potential, and an in-line filter to prevent cellular debris and aggregates from entering the nanopore region. Devices were tested with and without the channels coated with a short-chain PEG silane to minimize electroosmotic flow and permit an accurate measurement of the electrophoretic mobility and zeta potential of the EVs. To enhance throughput of EVs, vacuum was applied to the waste reservoir to increase particle frequencies up to 1000 min-1. The nanopores had cross-sections 200 nm wide and 200 nm deep and easily resolved EV diameters from 60 to 160 nm. EVs from bovine milk and human breast cancer cells had similar particle size distributions, but their zeta potentials differed by 2-fold, -8 ± 1 and -4 ± 1 mV, respectively.

Breast Neoplasms , Extracellular Vesicles , Nanopores , Humans , Female , Electrophoresis , Electroosmosis
Anal Chem ; 95(45): 16453-16458, 2023 11 14.
Article En | MEDLINE | ID: mdl-37916921

Synchronous coefficient of drag alteration refers to a multidimensional transport mechanism where a net drift of molecules is achieved under a zero-time-average alternating motive force by perturbing their drag coefficient synchronously with the applied force. An electrophoretic form of the method is often applied to focus and purify nucleic acids in a gel under rotating electric fields. However, this method requires lengthy operation due to the use of limited field strengths. Here, using DNA as target molecules, we demonstrate that the operation time can be reduced from hours to minutes by replacing polymer gel with a microfabricated artificial sieve. We also describe an electrophoretic protocol that facilitates the collection of purified DNA from the sieve, which is shown to yield amplifiable DNA from crude samples including the lysates of cultured cells and whole blood. The sieve can be further equipped with nucleic acid amplification and detection functions for a point-of-care diagnostic application.

DNA , Nucleic Acids , Electrophoresis/methods , Polymers , Nucleic Acid Amplification Techniques
Sci Rep ; 13(1): 17281, 2023 10 12.
Article En | MEDLINE | ID: mdl-37828082

Dielectrophoresis (DEP) is widely utilized for trapping and sorting various types of cells, including live and dead cells and healthy and infected cells. This article focuses on the dielectric characterization of erythrocytes (red blood cells or RBCs) by quantifying DEP crossover frequency using a novel point-and-planar microwell device platform. Numerical simulations using COMSOL Multiphysics software demonstrate that the distribution of the DEP force is influenced by factors such as the shape of the point electrode, spacing between the point and planar electrodes, and the type of bioparticle being investigated. The dependency on electrode spacing is experimentally evaluated by analyzing the DEP crossover response of erythrocytes. Furthermore, the results are validated against the traditional electrical characterization technique called electrorotation, which typically requires laborious fabrication and operation using quadrupole electrodes. Other significant factors, including erythrocyte storage age and the changes in cell properties over time since collection, osmolarity, and temperature, are also assessed to determine the optimal conditions for erythrocyte characterization. The findings indicate a significant difference between fresh and stored erythrocyte samples (up to 4 days), highlighting the importance of maintaining an isotonic medium for cell storage.

Erythrocytes , Stress, Physiological , Temperature , Electrophoresis/methods , Electrodes
Appl Microbiol Biotechnol ; 107(24): 7647-7655, 2023 Dec.
Article En | MEDLINE | ID: mdl-37815615

Immotile yeast cells were transiently moved in nonuniform sinusoidal electric fields using multiple pairs of micro-parallel cylindrical electrodes equipped with a sequential signal generator (SSG) to analyze cell viability at a clinical scale for the brewery/fermentation industry. Living yeast cells of Saccharomyces cerevisiae during the exponential-stationary phase, with a cell density of 1.15 × 105 cells mL-1 were suspended in sucrose medium. The conductivity (σs) was adjusted to 0.01 S m-1 with added KCl. Cells exposed in electric field strengths ranging from 32.89 to 40.98 kV m-1, exhibited positive dielectrophoresis (pDEP) with the lower critical frequencies (LCF) at 85.72 ± 3.59 kHz. The optimized value of LCF was shifted upwards to 780.00 ± 83.67 kHz when σswas increased to 0.10 S m-1. Dielectrophoretic and LCF spectra (translational speed of cells vs. electric field frequencies) of yeast suspensions during positive dielectrophoresis were analyzed in terms of the dielectric properties of the cell membrane and cytoplasm which reflect yeast cell viability and metabolic health status. The dielectrophoretic collection yield of cells using positive dielectrophoresis was reported on the monitor of sequential signal generator software to evaluate the number of living and dead cells through a real-time image processing analyzer. The spectra of both positive dielectrophoresis of the living and dead cells had distinguishable dielectric properties. The conductivity of the yeast cytoplasm (σc) of the dead cells was significantly less (≈ ≤ 0.05 S m-1) than that of the living yeast cells which typically had a cytoplasmic conductivity of ≈ 0.2 S m-1. This difference between viable and non-viable cells is sufficient for cell separation procedures. KEY POINTS: • Dielectrophoresis can be used to separate viable and non-viable yeast cells, • Cellular dielectric properties can be derived from the analysis of their dielectric spectra, • Cytoplasmic conductivity of viable cells is ≈ 0.2 S m-1 while that of non-viable cells ≈ ≤ 0.05 S m-1.

Electricity , Saccharomyces cerevisiae , Cytoplasm , Electric Conductivity , Cell Membrane , Electrophoresis/methods
Phys Chem Chem Phys ; 25(41): 28034-28042, 2023 Oct 25.
Article En | MEDLINE | ID: mdl-37846110

Nanopore-based biomolecule detection has emerged as a promising and sought-after innovation, offering high throughput, rapidity, label-free analysis, and cost-effectiveness, with potential applications in personalized medicine. However, achieving efficient and tunable biomolecule capture into the nanopore remains a significant challenge. In this study, we employ all-atom molecular dynamics simulations to investigate the capture of double-stranded DNA (dsDNA) molecules into graphene nanopores with varying positive charges. We discover a non-monotonic relationship between the DNA capture rate and the charge of the graphene nanopore. Specifically, the capture rate initially decreases and then increases with an increase in nanopore charge. This behavior is primarily attributed to differences in the electrophoretic force, rather than the influence of electroosmosis or counterions. Furthermore, we also observe this non-monotonic trend in various ionic solutions, but not in ionless solutions. Our findings shed light on the design of novel DNA sequencing devices, offering valuable insights into enhancing biomolecule capture rates in nanopore-based sensing platforms.

Graphite , Nanopores , DNA/analysis , Molecular Dynamics Simulation , Electrophoresis
Anal Methods ; 15(43): 5885-5890, 2023 11 09.
Article En | MEDLINE | ID: mdl-37905587

The active ingredients from tobacco extracts were continuously separated and purified using a homemade free-flow electrophoresis apparatus. A rectangular free flow electrophoresis device was constructed for the continuous separation and preparation, and the operating conditions of the device were optimized. The fractions obtained from the free-flowing component collection unit were then detected by HPLC and GC-MS. The results showed that a 90% methanol-water solution could maximize the extraction of the active components from tobacco. Chlorogenic acid and nicotine were enriched in three and four of 24 fractions, respectively, after free-flow isoelectric focusing electrophoresis. 2-Hydroxy-2-cyclopentene-1-one, 1-(2-methyl-1,3-oxathiolan-2-yl) ethanone, nornicotine, cotinine, and scopolamine were separated and enriched synchronously. Overall, the use of free-flow electrophoresis technology for the separation and purification of the active substances in tobacco can improve the comprehensive utilization rate of tobacco.

Cotinine , Electrophoresis , Isoelectric Focusing/methods , Chromatography, High Pressure Liquid
Electrophoresis ; 44(23): 1837-1846, 2023 Dec.
Article En | MEDLINE | ID: mdl-37753817

Malaria is a tropical disease caused by parasites in the genus Plasmodium, which still presents 241 million cases and nearly 627,000 deaths recently. In this work, we used the dielectrophoresis (DEP) to characterize red blood cells in a microchannel. The purpose of this work is to determine the difference between the normal and the malaria-infected cells based on the DEP characteristics. The samples were infected cells and normal red blood cells, which were either prepared in culture or obtained from volunteers. Diamond-shaped and curved micropillars were used to create different degrees of DEP in the gap between them. The DEP crossover frequencies were observed with the diamond-shaped micropillars. The cell velocity under negative dielectrophoresis (nDEP) at a low frequency was examined with the curved micropillars. The measured lower crossover frequencies were remarkably different between the malaria-infected cells and the normal cells, whereas the higher crossover frequencies were similar among the samples. The velocity under nDEP was lower for the infected cells than the normal cells. The results imply that the malaria infection significantly decreases the capacitance but increases the conductance of the cell membrane, whereas a change in cytoplasmic conductivity may occur in a later stage of infection.

Erythrocytes , Malaria , Humans , Cytoplasm , Cell Membrane , Electric Conductivity , Electrophoresis/methods
J Appl Lab Med ; 8(6): 1101-1114, 2023 11 02.
Article En | MEDLINE | ID: mdl-37725944

BACKGROUND: The serum-free immunoglobulin light chain assay has been recommended as a screening test for monoclonal gammopathy. We evaluated the usefulness of urine free immunoglobulin light concentration for selection of specimens for immunofixation electrophoresis. METHODS: Using kits from The Binding Site for Freelite ®, we validated examination of urine for measuring free κ and λ light chains. The results of urine free light chain concentrations were evaluated to ascertain if the results could be used to reduce the number of specimens requiring urine protein immunofixation electrophoresis. RESULTS: In the 515 specimens examined, there was no evidence of monoclonal gammopathy or history of monoclonal gammopathy in 331. Monoclonal κ or λ light chains were detectable in 42 and 30 specimens, respectively. There was history of κ or λ chain associated monoclonal gammopathy in 62 and 50 patients, respectively. In the 38 monoclonal κ positive urine specimens, with light chain data, κ/λ ratio was >5.83 in all specimens. In 27 specimens positive for monoclonal λ light chains, with light chain data, the urine λ/κ ratio was > 0.17 in 24 of 27 specimens and > 0.041 in all specimens. In patients without monoclonal gammopathy all specimens had a κ/λ ratio of >5.83 or λ/κ ratio >0.17. CONCLUSIONS: The Freelite ® assay from The Binding Site is suitable for quantification of free light chains in urine. In patients with known history of monoclonal gammopathy, urine immunofixation electrophoresis may be omitted in specimens with κ/λ ratio of <5.83 for κ associated lesions and λ/κ ratio of <0.041 for λ associated lesions. However, the results do not support using this test for first-time urine testing for monoclonal light chains as it is not predictive of positive result, nor does it exclude a monoclonal light chain in urine.

Monoclonal Gammopathy of Undetermined Significance , Paraproteinemias , Humans , Immunoglobulin Light Chains/urine , Paraproteinemias/diagnosis , Immunoglobulin lambda-Chains , Electrophoresis/methods
Lab Med ; 54(6): e201-e203, 2023 Nov 02.
Article En | MEDLINE | ID: mdl-37707512

Serum protein electrophoresis (SPE) and immunofixation (IFE) assays are commonly used to diagnose and monitor patients with multiple myeloma (MM). Identifying analytical interferences in SPE and IFE caused by therapeutic monoclonal antibodies (tmAbs) can be challenging. Here we report the case of a 72-year-old male with a long history of relapsed immunoglobulin (Ig)G kappa MM. A follow-up SPE showed the original peak plus 2 additional cathode peaks. Immunofixation was ordered as a reflex test to investigate the new peaks that showed initial patient monoclonal IgG kappa in addition to 2 restricted bands of the IgG kappa type. Therapeutic monoclonal antibody interference was suspected and the patient's chart was reviewed. The patient was not on any antimyeloma monoclonal antibody therapy. However, preexposure prophylaxis therapeutic monoclonal antibodies tixagevimab plus cilgavimab (Evusheld) for severe acute SARS-CoV-2 was administered approximately 45 minutes before sample collection, which led to the identifiable spikes and correlated bands. After 2 days, the IgG kappa bands disappeared, confirming this therapy's effect on SPE and IFE. Therefore, clinical pathologists should be aware of when providers prescribe new monoclonal antibody therapy and become familiar with the position of commonly prescribed (tmAbs) therapies at their institutions.

COVID-19 , Multiple Myeloma , Male , Humans , Aged , Spike Glycoprotein, Coronavirus , Blood Protein Electrophoresis/methods , COVID-19/diagnosis , SARS-CoV-2 , Electrophoresis , Antibodies, Monoclonal , Multiple Myeloma/diagnosis , Immunoglobulin G