-
Journal of Clinical Pathology Sep 1978Purified human spleen ferritin was labelled with 125I. On Sepharose 6-B gel filtration four species of labelled products were separated: a component with a higher...
Purified human spleen ferritin was labelled with 125I. On Sepharose 6-B gel filtration four species of labelled products were separated: a component with a higher molecular weight than ferritin; a component which is eluted in the same volume as unlabelled ferritin; and two labelled compounds with molecular weights lower than ferritin. When these labelled materials were used in a double antibody radioimmunoassay, the high molecular weight fraction showed variable and high non-specific binding and was poorly displaced by unlabelled ferritin; the fraction behaving like true ferritin gave good standard curves and showed non-specific binding of less than 1%. The remaining two components showed poor binding to rabbit antiferritin. Using labelled material from the second fraction, a double antibody radioimmunoassay capable of measuring 2 microgram ferritin protein/litre of serum was developed. Inter- and intra-assay variation was between 3% and 8% over a concentration range of 0 to 250 microgram ferritin protein/litre. Good agreement between serum ferritin levels assayed by the present method and by an immunoradiometric method was obtained. Labelled ferritin was stable for at least six weeks. The simplicity of the methodology makes it possible to assay serum ferritin in large batches.
Topics: Ferritins; Humans; Radioimmunoassay
PubMed: 711918
DOI: 10.1136/jcp.31.9.872 -
Journal of Veterinary Diagnostic... Mar 2023The Wellness Ready Test (WRT) is a lateral flow, stall-side assay that measures equine insulin in whole blood and requires validation before recommending clinical use....
The Wellness Ready Test (WRT) is a lateral flow, stall-side assay that measures equine insulin in whole blood and requires validation before recommending clinical use. We evaluated intra- and inter-assay precision and linearity and compared the WRT with a radioimmunoassay (RIA). Tested concentrations ranged from <139 to >695 pmol/L (<20 to >100 μIU/mL). For 20 replicates at each insulin level, intra-assay CVs of the WRT for insulin were 13.3%, 12.9%, and 15.3% at low (139-278 pmol/L; 20-40 μIU/mL), intermediate (278-417 pmol/L; 40-60 μIU/mL), and high (>417 >60 μIU/mL) concentrations, respectively. For 10 replicates at each level (3 assay lots), inter-assay CVs were 15.9%, 11.0%, and 11.7%, respectively. In the weighted linear regression of 5 measured insulin concentrations against expected concentrations, = 0.98, slope = 1.02, and y-intercept = 14.4 pmol/L (2.08 μIU/mL). The Spearman correlation coefficient () was 0.90 (95% CI: 0.85-0.94) between the WRT and RIA; the WRT = f(RIA) Passing-Bablok regression yielded the fit, y = 1.005x + 24.3 pmol/L (3.50 μIU/mL). The WRT result averaged 10.4% higher than the RIA result, with targeted bias of 25.9, 26.1, and 26.7 pmol/L (3.74, 3.76, and 3.84 μIU/mL) for cutoffs used to diagnose insulin dysregulation of 312, 347, and 451 pmol/L (45, 50, and 65 μIU/mL). Assay clinical sensitivities, specificities, and accuracies determined at the 3 selected clinical cutoffs and using the RIA as gold standard were 87-95%, 92-96%, and 91-95%, respectively ( = 99 samples). Observed total error was 28.4-30.4%. The WRT had acceptable precision, excellent linearity, and good association with the RIA.
Topics: Animals; Biological Assay; Horses; Insulin; Point-of-Care Systems; Radioimmunoassay; Sensitivity and Specificity; Reproducibility of Results
PubMed: 36482705
DOI: 10.1177/10406387221142288 -
Journal of Clinical Microbiology Mar 1975A radioimmunoassay procedure was developed for determining smallpox and vaccinia antibodies in human sera. The test detected and measured both primary and secondary... (Comparative Study)
Comparative Study
A radioimmunoassay procedure was developed for determining smallpox and vaccinia antibodies in human sera. The test detected and measured both primary and secondary immune responses in persons infected with variola virus or vaccinia virus. The antibody titers obtained by complement fixation, hemagglutination inhibition, plaque reduction neutralization, and radioimmunoassay methods were compared. In sequential serum specimens, the radioimmunoassay test indicated fourfold or greater increases in all of the smallpox patients and in six of eight vaccinated persons. Both the complement fixation and the hemagglutination inhibition tests were less effective. In persons who had been vaccinated, radioimmunoassay and plaque reduction neutralization tests appeared to measure the same immune response. However, in smallpox patients the immune response was readily detected by radioimmunoassay, whereas an immune response was not detected by the plaque reduction neutralization test when vaccinia virus was the antigen in the test system. Radioimmunoassay is an operationally simple procedure which provides objective and quantitative end-point titers in serological determinations.
Topics: Antibodies, Viral; Antibody Formation; Complement Fixation Tests; Evaluation Studies as Topic; Hemagglutination Tests; Humans; Neutralization Tests; Radioimmunoassay; Smallpox; Vaccination; Vaccinia virus; Variola virus
PubMed: 170309
DOI: 10.1128/jcm.1.3.311-317.1975 -
Journal of Nuclear Medicine : Official... Jul 1979
Topics: Environmental Health; Forensic Medicine; Hair; Humans; Opioid-Related Disorders; Radioimmunoassay
PubMed: 541720
DOI: No ID Found -
Journal of Veterinary Diagnostic... Jan 2022Determination of serum or plasma progesterone (P4) concentrations is important to recognize pregnant and non-pregnant ewes, and also to predict the number of carried...
Determination of serum or plasma progesterone (P4) concentrations is important to recognize pregnant and non-pregnant ewes, and also to predict the number of carried lambs. The 2 most common methodologies for the detection of plasma P4 are radioimmunoassay (RIA) and enzyme immunoassay (EIA). RIA is very expensive, and not all laboratories are equipped to perform this test; EIA is commercially available for human use, but only a few companies produce species-specific kits, which are expensive. We verified for ovine plasma a less expensive and easily available ELISA kit (DiaMetra) designed to quantify P4 in humans. Pools of ovine and human plasma were used to compare repeatability, accuracy, sensitivity, and stability of P4 measured by the DiaMetra kit. Repeatability data were within 15%, and accuracy values were ~90% for both plasma matrices. Stability data showed a loss of <20% for freeze-thaw and <30% for 30-d storage. All parameters were acceptable under international guidelines for method validation. The human ELISA kit was used successfully to quantify plasma P4 in 26 ewes during pregnancy until delivery. P4 concentrations were also correlated with the number of carried lambs.
Topics: Animals; Enzyme-Linked Immunosorbent Assay; Female; Humans; Immunoenzyme Techniques; Pregnancy; Progesterone; Radioimmunoassay; Sheep
PubMed: 34470514
DOI: 10.1177/10406387211043513 -
Clinical Immunology (Orlando, Fla.) Nov 2007The predominant autoantibody assays employed in basic immunologic studies are variations of solid-phase assays where autoantigens are bound to 96-well plates. Though the... (Comparative Study)
Comparative Study Review
The predominant autoantibody assays employed in basic immunologic studies are variations of solid-phase assays where autoantigens are bound to 96-well plates. Though the assay format is convenient and often appropriate for studies of induced immune responses in inbred strains of mice, we will argue that this assay format usually, but not always, leads in clinical medicine to what should be unacceptable false positive results as well as lower sensitivity compared to the current generation of high throughput fluid-phase radioassays. Utilizing simple in vitro transcription and translation labeling of autoantigens, it is now possible to rapidly create fluid-phase radioassays for most (but not all) autoantigens, thereby allowing direct comparison between the different assay formats. In addition, adding a fluid-phase competition step to both solid-phase ELISA assays and even fluid-phase radioassays can enhance specificity. Development in a field of such assays with excellent specificity and sensitivity (e.g. studies of type 1A diabetes) is fostered by Societies sponsoring workshops where blinded samples are evaluated with "competing" assay formats for sensitivity, specificity, and reproducibility.
Topics: Autoantibodies; Autoantigens; Autoimmune Diseases; Enzyme-Linked Immunosorbent Assay; Humans; Radioimmunoassay; Reproducibility of Results; Sensitivity and Specificity
PubMed: 17904423
DOI: 10.1016/j.clim.2007.08.005 -
Journal of Veterinary Internal Medicine Mar 2017Many diagnostic tests for insulin dysregulation use reference intervals established with an insulin radioimmunoassay (RIA) that is no longer available. A...
BACKGROUND
Many diagnostic tests for insulin dysregulation use reference intervals established with an insulin radioimmunoassay (RIA) that is no longer available. A chemiluminescent immunoassay (CLIA) is commonly used for the measurement of serum insulin concentration in clinical practice but requires further validation, especially at clinically relevant reference intervals.
OBJECTIVES
To evaluate the CLIA for measurement of equine insulin and compare it to the previously validated, but now unavailable RIA.
SAMPLES
Equine serum samples (n = 78) from clinical and experimental studies.
METHODS
In this experimental study, performance of the CLIA was evaluated using standard variables, including comparison with the RIA. Continuous and binary outcomes were analyzed.
RESULTS
The CLIA showed good intra-assay (coefficient of variation [CV], 1.8-2.4%) and interassay (CV, 3-7.1%) precision. Acceptable recovery on dilution (100 ± 10%) was achieved only at dilutions <1:1. Recovery on addition was acceptable. Comparison of the CLIA and RIA showed strong positive correlation (r = 0.91-0.98), with fixed and proportional bias. At 3 diagnostic cutoffs, sensitivity of CLIA compared with RIA ranged from 67 to 100% and specificity from 96 to 100%.
CONCLUSIONS AND CLINICAL IMPORTANCE
The CLIA is a highly repeatable assay which is suitable for within- and between-horse comparisons. Dilution of high concentration samples should be performed with charcoal-stripped serum (CSS) and at the lowest dilution factor possible. At concentrations commonly used for diagnosis of insulin dysregulation (≤100 μIU/mL), results from the CLIA tend to be lower than from the RIA and should be interpreted accordingly. Further standardization of equine insulin assays is required.
Topics: Animals; Horses; Immunoassay; Insulin; Luminescent Measurements; Radioimmunoassay; Reproducibility of Results; Sensitivity and Specificity
PubMed: 28124389
DOI: 10.1111/jvim.14657 -
The AAPS Journal Mar 2014As part of the GBC (Global Bioanalysis Consortium), the L3 assay format team has focused on reviewing common platforms used to support ligand binding assays in the... (Review)
Review
As part of the GBC (Global Bioanalysis Consortium), the L3 assay format team has focused on reviewing common platforms used to support ligand binding assays in the detection of biotherapeutics. The following review is an overview of discussions and presentations from around the globe with a group of experts from different companies to allow an international harmonization of common practices and suggestions for different platforms. Some of the major platforms include Gyrolab, Erenna, RIA, AlphaLISA, Delfia, Immuno-PCR, Luminex, BIAcore, and ELISAs. The review is meant to support bioanalysts in taking decisions between different platforms depending on the needs of the analyte with a number of recommendations to help integration of platforms into a GLP environment.
Topics: Cooperative Behavior; Enzyme-Linked Immunosorbent Assay; Ligands; Polymerase Chain Reaction; Practice Guidelines as Topic; Radioimmunoassay
PubMed: 24343771
DOI: 10.1208/s12248-013-9552-9 -
The Tohoku Journal of Experimental... Oct 1976A new procedure for radioimmunoassay (RIA) was applied to determine the serum concentration of thyroxine (T4). Mixtures of T4-methylester hydrochloride-bovine serum...
A new procedure for radioimmunoassay (RIA) was applied to determine the serum concentration of thyroxine (T4). Mixtures of T4-methylester hydrochloride-bovine serum albumin complex and complete Freund's adjuvant were injected to rabbits to get them immunized. Specific anti-T4 rabbit serum, high in titer, could be obtained 18 months after the start of immunization. RIA for T4 extracted by ethanol from serum was performed by an application of dextran-coated charcoal to separate bound and free 125-i-t4. on the other hand, RIA for T4 performed directly in the serum containing 100 mg/100 ml of 8-anilino-1-naphthalene-sulfonic acid (ANS) gave a similar standard curve for T4 obtained by the ethanol-extraction method. Serum T4 values obtained by the methanol-extraction method were 9.7 +/- 3.3 mug/100 ml for patients with hyperthyroidism and 0.6 +/- 0.3 mug/100 ml for those with hypothyroidism. The corresponding figures obtained by RIA in the serum containing ANS were 11.1 +/- 2.1, 19.1 +/- 3.3 and 0.7 +/- 0.7 mug/100 ml, respectively. The figures positively correlated respectively to the serum T4 values obtained by the competitive protein-binding analysis method (Tetrasrob-125).
Topics: Humans; Radioimmunoassay; Thyroxine
PubMed: 982432
DOI: 10.1620/tjem.120.125 -
Antimicrobial Agents and Chemotherapy Oct 1982Radioimmunoassay and enzyme immunoassay methods for analysis of serum gentamicin levels have been shown to be comparable. The purpose of this study was to determine if... (Comparative Study)
Comparative Study
Radioimmunoassay and enzyme immunoassay methods for analysis of serum gentamicin levels have been shown to be comparable. The purpose of this study was to determine if serum concentration-time data from the same patient assayed by radioimmunoassay and enzyme immunoassay would provide the same estimates for half-life, elimination rate constant, distribution volume, drug clearance, and gentamicin dose. A total of 103 pre- and postinfusion serum samples were obtained from 32 patients. The samples were divided and assayed by radioimmunoassay and enzyme immunoassay. Serum concentration-time data were fitted to a one-compartment model, and kinetic calculations were performed using the method of Sawchuk et al. (Clin. Pharmacol. Ther. 21:362-369, 1977). While good correlation was established between the two assay methods, significant (P less than 0.05) mean differences were seen in distribution volume (25%), gentamicin clearance (15%), and half-life (11%), using the quantitative data from both methods. Because of differences noted in these pharmacokinetic parameters, significant differences were also noted in dosage calculations. We conclude that there are differences in the pharmacokinetic parameters obtained using results from the radioimmunoassay and enzyme immunoassay. These differences also translate into significant differences between dosage recommendations when individualization of the gentamicin regimen is attempted.
Topics: Adolescent; Adult; Aged; Female; Gentamicins; Half-Life; Humans; Immunoenzyme Techniques; Kinetics; Male; Middle Aged; Radioimmunoassay
PubMed: 6758688
DOI: 10.1128/AAC.22.4.648