scholarly journals MON-477 Anti-Streptavidin Interference in Multiple Hormones Immunoassays: Case Report

2020 ◽  
Vol 4 (Supplement_1) ◽  
Author(s):  
Luciana Pinto Brito ◽  
Aline Lenczuk ◽  
Luciana Leopoldino ◽  
Valeria Samuel Lando ◽  
Berenice Bilharinho Mendonca ◽  
...  
Keyword(s):  
Solid Phase ◽  
High Specificity ◽  
Turnaround Time ◽  
Repeated Measurements ◽  
Normal Range ◽  
Free T4 ◽  
Analytical Interference ◽  
Clinical Pictures ◽  
Antigen Antibody ◽  
Initial Results

Abstract Automated immunoassays are the most commonly current methods used in clinicial laboratory to hormone tests, due short turnaround time and high specificity and sensibility. However immunoassays are not free from interferences. Several immunoassays use biotin-streptavidin interaction to anchor antigen-antibody complexes in solid phase and so are susceptible to biotine intake or anti-streptavidin antibody. In sample with these interferents, the results in competitive assays are falsely high and in non-competitive assays are falsely low. OBJECTIVE: To report a case of multiple hormones immunoassay interference by an anti-streptavidin antibody. MATERIAL AND METHODS: A 11-years-old boy with child obesity, and no other symptoms, had discordant laboratory results with markedly elevated free T4, total T4 and total T3 with normal TSH. Repeated measurements in the same sample and in a new collected sample confirmed the initial results and revealed low PTH and high TRAb without hypocalcemia or hyperthiroidism clinical pictures. All the parameters were measured on the automated Cobas e602, Roche plataform.The patient and your family denied biotin ingestion, so anti-streptavidin interference could explain the multiple interference.The serum was pre-incubated with streptavidin microparticles during an hour and centrifuged for 10min (3000 rpm) to removed the analytical interference. RESULTS: The results of post-incubation with microparticles were all in the normal range. Three control samples were not affected by the incubation. Since luminescence is inversely proportional to analyte concentration in competitive assays, low signals lead to falsely high levels (like in free T4, total T4, Total T3 and TRAb in our patient). The reverse occurs with immunometric assays, in which low signals result in falsely reduced values (like in PTH in our patient). CONCLUSION: In literature, streptavidin antibodies seem to be a rare occurrence. In samples with biotin or anti-streptavidin suspection, pre-incubation with streptavidin microparticles is a simple and effective procedure to remove this interference.

Increased Serum Concentration of Free L-Triiodothyronine in Patients Treated with L-Thyroxine

1983 ◽  
Vol 22 (05) ◽  
pp. 251-254
Author(s):  
R. Schmitz ◽  
H. Bongers ◽  
A. Löw ◽  
J. Mahlstedt ◽  
K. Joseph ◽  
...  
Keyword(s):  
Oral Dose ◽  
Serum Concentration ◽  
Normal Level ◽  
Binding Sites ◽  
Carrier Proteins ◽  
Normal Range ◽  
Free T4 ◽  
Normal Concentration ◽  
Free T3 ◽  
High Doses

This study demonstrates that in spite of measured normal concentrations of carrier proteins one cannot deduce in all cases a normal fT3 from a normal level of TT3 when 1-thyroxine given for diagnostic or therapeutic purposes is present in excess. The displacement of 1-triiodothyronine from its binding sites is shown in 35 patients with non-toxic goitre who received an oral dose of 200 μg 1-thyroxine/die for two weeks. Apart from a significant increase of TT4 (from 7.85 to 14.21 μg/dl ≙ + 81 %) and of fT4 (from 1.58 to 3.7 ng/dl ≙ + 134%) there is only a slight increase in TT3 from 148 to 158 ng/dl (≙ + 10%) after 14 days of treatment. By contrast fT3 rises clearly from 4.97 to 8.07 pg/ml ≙ + 63% (normal range: 2.8-5.6 pg/ml). Compared with the increase of TT3 (+ 10%) the free T3 rises by a factor of 6.3 (63 %/10%). On account of higher affinity of 1-thyroxine to binding proteins the free T4 is influenced to a lesser degree. Compared with the increase of TT4 (+ 81 %) free T4 rises by a factor of 1.6 (134%/81 %). It is supposed that the serum concentration of free T3 can be increased despite a normal concentration of TT3 when 1-thyroxine is present in excess. Therefore, for laboratory work fT3 should be assigned a higher validity than TT3 when patients are treated with comparatively high doses of 1-thyroxine.

A Nylon Filter A-ELISA for Detecting Viruses in Water

1993 ◽  
Vol 27 (7-8) ◽  
pp. 135-141 ◽  
Author(s):  
Abidelfatah M. Nasser ◽  
Yehudit Elkana ◽  
Leon Goldstein
Keyword(s):  
Positive Result ◽  
Solid Phase ◽  
Enteric Viruses ◽  
High Specificity ◽  
Negative Results ◽  
Order Of Magnitude ◽  
Lower Background

This study was designed to develop a modification of A-ELISA performed in microtitre plates. Nylon filters have been utilized successfully as a solid phase for the performance of A-ELISA. The use of nylon filters resulted in lower background than nitro-cellulose and paper filters, indicating their suitability as a solid phase for developing A-ELISA. With enteric viruses, human rotaviruses and MS-2 coliphage, negative results were obtained, suggesting high specificity of the developed technique for poliovirus 1. The sensitivity of the developed A-ELISA has been shown to be at least one order of magnitude greater than ordinary ELISA. A positive result with the nylon A-ELISA can be obtained with samples containing 100-1000 pfu/ml of poliovirus. Up to date methods used for detecting viruses in water are elaborate, time consuming and costly. Applying the nylon A-ELISA may overcome some of these disadvantages.

Personalized antibiotic therapy – a rapid high performance liquid chromatography–tandem mass spectrometry method for the quantitation of eight antibiotics and voriconazole for patients in the intensive care unit

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Tony Böhle ◽  
Ulrike Georgi ◽  
Dewi Fôn Hughes ◽  
Oliver Hauser ◽  
Gudrun Stamminger ◽  
...  
Keyword(s):  
Intensive Care ◽  
Antibiotic Therapy ◽  
High Performance ◽  
High Specificity ◽  
Serum Levels ◽  
Turnaround Time ◽  
Target Range ◽  
Therapeutic Drug ◽  
Monitoring Method ◽  
Adjustment Procedure

AbstractObjectivesFor a long time, the therapeutic drug monitoring of anti-infectives (ATDM) was recommended only to avoid the toxic side effects of overdosing. During the last decade, however, this attitude has undergone a significant change. Insufficient antibiotic therapy may promote the occurrence of drug resistance; therefore, the “one-dose-fits-all” principle can no longer be classified as up to date. Patients in intensive care units (ICU), in particular, can benefit from individualized antibiotic therapies.MethodsPresented here is a rapid and sufficient LC-MS/MS based assay for the analysis of eight antibiotics (ampicillin, cefepime, cefotaxime, ceftazidime, cefuroxime, linezolid, meropenem, and piperacillin) applicated by continuous infusion and voriconazole. In addition a dose adjustment procedure for individualized antibiotic therapy has been established.ResultsThe suggested dose adjustments following the initial dosing of 121 patient samples from ICUs, were evaluated over a period of three months. Only a minor percentage of the serum levels were found to be within the target range while overdosing was often observed for β-lactam antibiotics, and linezolid tended to be often underused. The results demonstrate an appreciable potential for β-lactam savings while enabling optimal therapy.ConclusionsThe presented monitoring method provides high specificity and is very robust against various interferences. A fast and straightforward method, the developed routine ensures rapid turnaround time. Its application has been well received by participating ICUs and has led to an expanding number of hospital wards participating in ATDM.

Evaluation of the first immunosuppressive drug assay available on a fully automated LC-MS/MS-based clinical analyzer suggests a new era in laboratory medicine

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Sebastian Hörber ◽  
Andreas Peter ◽  
Rainer Lehmann ◽  
Miriam Hoene
Keyword(s):  
High Specificity ◽  
Turnaround Time ◽  
Immunosuppressive Drugs ◽  
Immunosuppressive Drug ◽  
Ease Of Use ◽  
Analytical Performance ◽  
University Hospital ◽  
Therapeutic Monitoring ◽  
Mean Deviation ◽  
Liquid Chromatography Tandem Mass

AbstractObjectivesDue to its high specificity, liquid chromatography-tandem mass spectrometry (LC-MS/MS) is considered the gold standard in diagnostic areas such as therapeutic monitoring of immunosuppressive drugs (ISDs). However, many laboratories still rely on immunoassays for ISD quantification in a tradeoff between analytical performance and the advantages of fully automated analyzers – shorter turnaround times, greater ease of use, and 24/7 availability.MethodsThe LC-MS/MS-based Thermo Scientific™ Cascadion™ SM Immunosuppressant Panel was evaluated for >6 months in the routine laboratory of a university hospital. We assessed the analytical performance of the panel and compared it to conventional LC-MS/MS as well as to immunoassays (cyclosporine A, sirolimus, tacrolimus (Siemens) and everolimus (Thermo Fisher)). In addition, both ISD panel and Cascadion analyzer were scrutinized with regards to, e.g., turnaround time, usability, and robustness.ResultsAll ISDs showed high linearity and precision (CV≤6%) and a good correlation with conventional LC-MS/MS. The mean deviation to the immunoassays was 17–19% and negative for all ISDs except everolimus with a positive 19% bias. No weak points were revealed when challenging assay and system with, e.g., high haematocrit, sedimented whole blood or priority samples. The Cascadion integrated well into our 24/7 routine and could easily be operated simultaneously with several other analyzers by technical staff without LC-MS experience.ConclusionsThe ISD panel showed excellent analytical performance and demonstrated that a fully automated LC-MS-based analysis starting from primary samples is feasible, suggesting that LC-MS could become an integral part of 24/7 diagnostics in the near future.

scholarly journals A rapid and affordable point of care test for antibodies against SARS-CoV-2 based on hemagglutination and artificial intelligence interpretation

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Vanessa Redecke ◽  
Kazuki Tawaratsumida ◽  
Erin T. Larragoite ◽  
Elizabeth S. C. P. Williams ◽  
Vicente Planelles ◽  
...  
Keyword(s):  
Test Performance ◽  
Learning Algorithm ◽  
Point Of Care ◽  
Method Comparison ◽  
High Specificity ◽  
Turnaround Time ◽  
Analysis Tool ◽  
Point Of Care Test ◽  
Specificity And Sensitivity ◽  
A Cell

AbstractDiagnostic tests that detect antibodies (AB) against SARS-CoV-2 for evaluation of seroprevalence and guidance of health care measures are important tools for managing the COVID-19 pandemic. Current tests have certain limitations with regard to turnaround time, costs and availability, particularly in point-of-care (POC) settings. We established a hemagglutination-based AB test that is based on bi-specific proteins which contain a dromedary-derived antibody (nanobody) binding red blood cells (RBD) and a SARS-CoV-2-derived antigen, such as the receptor-binding domain of the Spike protein (Spike-RBD). While the nanobody mediates swift binding to RBC, the antigen moiety directs instantaneous, visually apparent hemagglutination in the presence of SARS-CoV-2-specific AB generated in COVID-19 patients or vaccinated individuals. Method comparison studies with assays cleared by emergency use authorization demonstrate high specificity and sensitivity. To further increase objectivity of test interpretation, we developed an image analysis tool based on digital image acquisition (via a cell phone) and a machine learning algorithm based on defined sample-training and -validation datasets. Preliminary data, including a small clinical study, provides proof of principle for test performance in a POC setting. Together, the data support the interpretation that this AB test format, which we refer to as ‘NanoSpot.ai’, is suitable for POC testing, can be manufactured at very low costs and, based on its generic mode of action, can likely be adapted to a variety of other pathogens.

scholarly journals Cytohistopathological Study of Salivary Gland Lesions in Bundelkhand Region, Uttar Pradesh, India

2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
Anita Omhare ◽  
Sanjeev Kumar Singh ◽  
Jitendra Singh Nigam ◽  
Ankit Sharma
Keyword(s):  
Salivary Gland ◽  
Low Cost ◽  
Uttar Pradesh ◽  
Diagnostic Technique ◽  
High Specificity ◽  
Turnaround Time ◽  
Malignant Tumours ◽  
Female Ratio ◽  
Specificity And Sensitivity ◽  
Benign Tumours

Background. FNAC is a useful method for evaluating suspicious salivary glands lesions due to its low cost, minimum morbidity, rapid turnaround time, high specificity, and sensitivity. Aim. To know the frequency of the salivary gland lesions and cytohistological correlation in the Jhansi region, Uttar Pradesh, India. Material and Methods. In present study 124 cases were included and cytohistological correlation was made in 86 cases only. FNA was performed by using a 23/24-gauge needle without local anaesthesia. Air dried and 95% ethyl alcohol fixed wet smears were stained with Giemsa stain and Papanicolaou stain, respectively. Paraffin embedded tissue sections were stained with Haematoxylin and Eosin. Results. Parotid gland was the most commonly involved salivary gland. The commonest age group was 20 to 29 years, 30 to 39 years, and 60 to 69 years for nonneoplastic lesions, benign tumours, and malignant tumours, respectively. The overall male to female ratio was 1.17 : 1. The diagnostic accuracy of FNAC was 100%, 93.3%, and 88.2% for nonneoplastic lesions, benign tumours, and malignant tumours, respectively. Conclusion. The high accuracy, sensitivity, and specificity of FNAC confirm that preoperative cytology is a useful, quick, reliable diagnostic technique for rapid diagnosis and suitable for developing countries.

Colorimetric solid-phase minisequencing assay illustrated by detection of alpha 1-antitrypsin Z mutation

1993 ◽  
Vol 39 (11) ◽  
pp. 2282-2287 ◽  
Author(s):  
L Harju ◽  
T Weber ◽  
L Alexandrova ◽  
M Lukin ◽  
M Ranki ◽  
...  
Keyword(s):  
Solid Phase ◽  
Colorimetric Assay ◽  
Point Mutations ◽  
High Specificity ◽  
Microtiter Plate ◽  
Test Results ◽  
Single Nucleotide ◽  
Nitrophenyl Phosphate ◽  
Simple Alternative ◽  
Alpha 1 Antitrypsin

Abstract In solid-phase minisequencing, a defined point mutation is detected in microtiter plate-immobilized DNA by a single nucleotide primer extension reaction. We have here developed the method into a colorimetric assay and applied it to the detection of the Z mutation of the alpha 1-antitrypsin gene. We used novel nucleoside triphosphates modified with dinitrophenyl (DNP) hapten, permitting detection by anti-DNP-alkaline phosphatase conjugate, with p-nitrophenyl phosphate as substrate. The Z mutation is detected in two reactions: DNP-labeled dCTP is incorporated when the template is normal, DNP-dUTP when the Z mutation is present. Both modified nucleotides were incorporated with high specificity and with an efficiency similar to that of unmodified nucleotides. The test results are measured by spectrophotometry, yielding quantitative absorbance values. Calculation of the ratio of C to U signal permitted unambiguous distinction of normal homozygous, ZZ homozygous, and ZM heterozygous genotypes. The colorimetric minisequencing assay is rapid, standardized, and automatable, and thus provides an accurate and simple alternative for the analysis of known point mutations.

Monoclonal antibodies used in solid-phase and liquid-phase assays, as exemplified by progesterone assay.

1987 ◽  
Vol 33 (8) ◽  
pp. 1331-1337 ◽  
Author(s):  
W Schramm ◽  
T Yang ◽  
A R Midgley
Keyword(s):  
Monoclonal Antibodies ◽  
Liquid Phase ◽  
Solid Phase ◽  
Protein A ◽  
High Specificity ◽  
Binding Properties ◽  
Affinity Constants ◽  
Hybridoma Cell Lines ◽  
One Year ◽  
Better Than

Abstract Two immunoglobulins secreted by hybridoma cell lines have been systematically investigated to determine if they could be used in solid-phase assays to give results comparable with those obtained by conventional liquid-phase radioimmunoassay (RIA). The antibodies, BQ.1 and BQ.2, bind with high specificity to the steroid hormone progesterone. The affinity constants, Ka, to 125I-labeled progesterone derivatives are 1.1 X 10(11) L/mol and 9.1 X 10(9) L/mol, respectively. Progesterone inhibited the binding of radioiodinated derivatives (amides of tyramine, histamine, and tyrosine methylester with 11 alpha-progesterone hemisuccinate) equally well. For solid-phase assays, we immobilized antibody BQ.1 via Protein A to different polystyrene surfaces (about 30 pg per tube at 50% inhibition of radiolabeled tracer). Under these conditions, the performance of this antibody for the quantification of progesterone was equivalent to that obtained in RIA. For the immobilized antibody BQ.2, only 1/10 of the amount used for optimal results in RIA was required in solid-phase assays. Binding of either antibody to the antigen was undiminished after several freezing-thawing cycles. When immobilized on solid matrices, both antibodies retained up to 95% of their binding properties for one year. Thus high-affinity, high-specificity monoclonal antibodies can be obtained for haptens and, when suitably immobilized, can be used in solid-phase assays with results equal to or better than those obtained with liquid RIA.

Competitive enzyme-linked immunoassay for Factor VIII antigen.

1979 ◽  
Vol 25 (11) ◽  
pp. 1924-1927 ◽  
Author(s):  
L D Yorde ◽  
C V Hussey ◽  
D E Yorde ◽  
E A Sasse
Keyword(s):  
Horseradish Peroxidase ◽  
Factor Viii ◽  
Peroxidase Activity ◽  
Solid Phase ◽  
Microtiter Plate ◽  
Antigen Binding ◽  
Normal Range ◽  
Antigen Concentration ◽  
Soluble Complex ◽  
Factor Viii Antigen

Abstract We describe a competitive enzyme-linked immunoassay for Factor VIII antigen. Binding of anti-factor VIII to solid-phase Factor VIII antigen is competitively inhibited by the free factor VIII antigen that is to be measured. The amount of anti-Factor VIII bound to solid-phase VIII is measured by applying in sequence a heterologous bridging antibody and a soluble antibody/enzyme immune complex. The soluble complex used was rabbit antiperoxidase/horseradish peroxidase. Peroxidase activity is inversely proportional to the Factor VIII antigen concentration in the original test plasma and is measured spectrophotometrically. The assay can be performed in as little as 4 h with only a microtiter plate, antisera, antigen, and a spectrophotometer. It is sensitive to 0.05 units of Factor VIII antigen per milliliter, and reproducibility, linearity, and normal range are similar to those reported for other techniques.

A solid-phase enzyme-linked immunosorbent assay for the quantitation of human plasma alpha 1-acid glycoprotein.

1979 ◽  
Vol 25 (4) ◽  
pp. 546-549 ◽  
Author(s):  
H P Wang ◽  
C Y Chu
Keyword(s):  
Alkaline Phosphatase ◽  
Human Plasma ◽  
Immunosorbent Assay ◽  
Specific Antibody ◽  
Solid Phase ◽  
Enzyme Linked Immunosorbent Assay ◽  
Normal Range ◽  
Oral Contraceptive Pills ◽  
Acid Glycoprotein ◽  
Contraceptive Pills

Abstract We describe a solid-phase enzyme-linked immunosorbent assay for alpha 1-acid glycoprotein in human plasma. Plasma samples are incubated with alkaline phosphatase-linked, purified alpha 1-acid glycoprotein in alpha 1-acid glycoprotein-specific antibody-coated polystyrene tubes. The alkaline phosphatase that becomes attached to the tube via an immunological reaction between the alpha 1-acid glycoprotein and the specific antibody is measured spectrophotometrically. This assay is accurate reproducible, simple, and economical. As little as 4 microgram of alpha 1-acid glycoprotein per liter can be detected. The normal range for alpha 1-acid glycoprotein in the plasma of healthy adults, as measured by this method, is 0.48-1.27 g/L; the range is significantly different, 0.29-0.73 g/L, for women who are taking oral contraceptive pills.

Sign in / Sign up

Export Citation Format

Share Document