PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Fluorescence Polarization Immunoassay”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 recordsLinked to original sources
PubMed1996

Instability of standard calibrators may be involved in overestimating vancomycin concentrations determined by fluorescence polarization immunoassay.

Fluorescence polarization immunoassay (FPIA) is widely used to determine serum vancomycin concentrations, and it has been shown to over-estimate vancomycin concentrations in sera from renally impaired patients. This phenomenon has generally been thought to result from interference by vancomycin crystalline degradation products (CDP-1). In this study, we confirmed that serum vancomycin concentrations in various patients determined by FPIA were higher than those determined by high-performance liquid chromatography (HPLC) or enzyme multiplied immunoassay (EMIT). However, the quantitative differences in the serum vancomycin concentrations determined by FPIA versus HPLC were higher than the CDP-1 concentrations, even when the cross-reactivity of FPIA to CDP-1 is assumed to be 100%. When the vancomycin calibrators for FPIA were stored at 4 degrees C for 30 days, their concentrations determined by FPIA and HPLC decreased by 14 and 20%, respectively, and CDP-1 corresponding to 20% of primary vancomycin was formed. When stored at 25 degrees C, the degradation of vancomycin was more marked. We concluded that not only the cross-reactivity of FPIA to CDP-1 but also the instability of calibrators may cause the overestimation of serum vancomycin concentrations determined by FPIA.

Aged↗
PubMed1988

Measurement of angiotensinogen in human serum by fluorescence polarization immunoassay.

Fluorescence polarization immunoassay (F.P.I.A.) has rarely been used to measure components of the renin system. Using an Abbott TDX polarimeter and fluorescein - labelled angiotensin I as a tracer we measured angiotensin I by F.P.I.A. Combining this procedure with a renin incubation step enabled measurement of angiotensinogen in human serum. Using sera from male patients and from pregnant females, a good correlation between radioimmunoassay (R.I.A.) and F.P.I.A. was found. Two procedures were developed; one involving taking samples from the renin incubation mixture, the other involving measurement of generated angiotensin I at intervals without interrupting the renin incubation procedure. F.P.I.A. is less expensive and somewhat simpler than R.I.A. but, with the instrument used, it was less sensitive. An unexpected observation was that human renin increases polarization in solutions containing fluorescein labelled angiotensin I, indicating possible binding of renin to angiotensin I.

Angiotensin I↗
PubMed1992

Evaluation of instrumental, nonisotopic immunoassays (fluorescence polarization immunoassay and enzyme-multiplied immunoassay technique) for cyclosporine monitoring in whole blood after kidney and liver transplantation.

Two new instrumental methods, an enzyme-multiplied immunoassay technique (EMIT) and a fluorescence polarization immunoassay (FPIA), were evaluated for monitoring of cyclosporine (CyA) in whole blood samples of renal and liver transplant patients. They are considered as being specific to the parent drug and they were compared with a specific radioimmunoassay (RIA) and a nonspecific FPIA. The data reveal that the novel procedures provide slightly overestimated CyA levels compared with specific RIA (6-12% for EMIT, 20-25% for FPIA). For both assays, intrarun and interrun reproducibilities were found to be in the 2-8% range. The ease of performance and the possibility of performing approximately 40 assays/h make the two methodologies very attractive for both routine and emergency analyses. These approaches are viewed to be complementary to the only previously available instrumental method, the nonspecific FPIA, which provides three- to fourfold higher CyA levels than those obtained with specific methods. Specific and nonspecific monitoring of CyA levels allowed variations in proportions of metabolites to total CyA and metabolites to be distinguished. A higher percentage and variability of cross-reacting metabolites were found in whole blood samples after liver transplantation compared with those in blood of kidney transplant recipients.

Cyclosporine↗
PubMed1992

Evaluation of the Boehringer Mannheim ES 300 immunoassay analyzer and comparison with enzyme immunoassay, fluorescence polarization immunoassay, and radioimmunoassay methods.

The ES 300 (Boehringer Mannheim Diagnostics, Indianapolis, IN) is a new automated immunoassay analyzer intended for the quantitative determination of a wide range of analytes. We compared its performance to enzyme immunoassay (EIA), fluorescence polarization immunoassay (FPIA), and radioimmunoassay (RIA) methods for cortisol, digoxin, ferritin, prolactin, T4-uptake, total-T3, and TSH. The ES 300 methods showed excellent precision and the manufacturers' linearity claims were met in all cases. Cortisol, prolactin, total-T3, and TSH showed no bias and acceptable correlation with other methods. Digoxin, ferritin and total T4 showed positive bias but acceptable correlation. The ES 300 T4-uptake correlated poorly with the TDx method and showed positive bias; however, these assays appear comparable (although deficient) in diagnostic sensitivity when compared to TSH and T4 data for the same patient population. In all, we found the ES 300 to be an acceptable instrumental alternative for the high volume immunoassay laboratory.

Blood Chemical Analysis↗
PubMed1984

Analytical accuracy of determinations of aminoglycoside concentrations by enzyme multiplied immunoassay, fluorescence polarization immunoassay, and radioimmunoassay in the presence of heparin.

The accuracy of gentamicin, netilmicin, and tobramycin concentration determinations by enzyme multiplied immunoassay technique (EMIT; Syva Corp., Palo Alto, Calif.), fluorescence polarization immunoassay (TDx; Abbott Diagnostics, Irving, Tex.), and radioimmunoassay were compared in the presence of 0 to 3,000 USP units of porcine heparin per ml. Gentamicin, netilmicin, and tobramycin concentrations determined by EMIT decreased by 10 and 50% in the presence of 75 and 1,000 USP units/ml, 2 and 5 USP units/ml, and 2 and 7.5 USP units/ml, respectively. Accuracy of the TDx and radioimmunoassay determinations, however, were not affected by the presence of heparin. Blood samples for the determination of gentamicin, netilmicin, and tobramycin by EMIT should not be collected in evacuated heparinized tubes.

Aminoglycosides↗
PubMed1987

Observed differences in amikacin pharmacokinetic parameters and dosage recommendations determined by enzyme immunoassay and fluorescence polarization immunoassay.

Enzyme immunoassay (EIA) and fluorescence polarization immunoassay (FPIA) methods are commercially available for quantitation of serum amikacin concentration. The purpose of this study was to determine if the two assay methods were comparable and would provide the same estimates for pharmacokinetic parameters and dosage recommendations. A total of 73 amikacin serum samples were used to evaluate the two assay techniques. Forty-four of these samples, obtained from 10 patients, were used to evaluate the comparability of pharmacokinetic parameters and dosage regimens. The correlation coefficient between the two assay methods was 0.98 (y = 1.03x + 0.64). There were substantial differences in assay performance noted in samples less than 10 mg/L, 10-20 mg/L, and greater than 20 mg/L, typical concentration ranges for serum sampling used in pharmacokinetic analysis. A difference of approximately 10% was observed in the determination of amikacin half-life, total body clearance, and dosage calculation. A 7% difference was noted in the volume of distribution. A significant difference (p less than 0.05) in volume of distribution and dosage recommendations was noted. Although the two methods for determining amikacin serum concentrations appear to be interchangeable on the basis of the in vitro comparison, significant differences were observed between the two assays in pharmacokinetic parameters and dosage recommendations.

Amikacin↗
PubMed1979

Direct fluorescence polarization immunoassay.

Direct fluorescence polarization immunoassay of serum cortisol was established. Non-specific binding of fluorescent-labelled cortisol to serum proteins was successively eliminated by sodium dodecyl sulfate. The minimal amount of cortisol detected was 0.1 ng/tube and serum concentration of 1.0 microgram/dl to 100 microgram/dl of cortisol could be measured. This fluorescence polarization immunoassay satisfied the standard criteria of accuracy and precision. The values correlated well with those obtained by radioimmunoassay.

Fluorescent Antibody Technique↗
PubMed1991

Comparison of enzyme immunoassay and fluorescence polarization immunoassay as techniques for measuring anticonvulsant drugs on the same analytical instrument.

We have applied kits for enzyme immunoassay and fluorescence polarization immunoassay of anticonvulsant drugs to the same centrifugal analyser. There was a good correlation between the two techniques for the assay of phenytoin, carbamazepine, and phenobarbitone. Within- and between-batch reproducibility was also comparable but only the fluorescence polarization system allowed the use of stored calibration curves. The ability to use stored curves may be particularly advantageous to laboratories required to run a large number of stat assays or who are handling low workloads of particular analytes.

Carbamazepine↗
PubMed1998

Comparison of capillary electrophoresis-based immunoassay with fluorescence polarization immunoassay for the immunodetermination of methamphetamine using various methamphetamine antibodies.

An accurate and simple immunoassay using capillary electrophoresis (CE) with laser-induced fluorescence (LIF) was performed for the detection of methamphetamine (MA) in urine. The CE-LIF was conducted with an untreated fused-silica column using antiserum and a tracer of fluorescein isothiocyanate (FITC)-labeled MA. This CE-LIF system was compared with fluorescence polarization immunoassay (FPIA) in a TDx analyzer in the photo-check mode using the same FITC-labeled tracer and the same antiserum. Various antibodies, not only those prepared by our own immunogens but also those from commercial sources, were screened and characterized in both assay systems with regard to sensitivity, precision, and cross-reactivity. Both systems satisfied analytical precision and gave similar cross-reactivity patterns. However, the CE-LIF-based immunoassay was approximately one order superior to FPIA in sensitivity, requiring less volume of sample, antiserum, and tracer for the assay. Considering that the FPIA system is well known to be a useful tool for screening antibodies and detecting drugs, the CE-LIF-based immunoassay system, which is seemingly more advantageous than the FPIA system, appears to have great power for the characterization of antibodies and for the detection of MA in urine.

Antibodies↗
PubMed1989

Evaluation of an enzyme immunochromatography method for carbamazepine: a comparison with enzyme-multiplied immunoassay technique, fluorescence polarization immunoassay, and high-performance liquid chromatography.

A noninstrumented enzyme immunochromatography (EIC) method for monitoring carbamazepine using whole blood was compared to the enzyme-multiplied immunoassay technique (EMIT), fluorescence polarization immunoassay (FPIA), and high-performance liquid chromatography (HPLC). Samples from 74 patients were evaluated in the comparison study, yielding correlation coefficients of 0.961 (EMIT), 0.974 (FPIA), and 0.867 (HPLC). The EIC method produced within-run coefficients of variation of 4.3%, 4.9%, and 5.8% for three carbamazepine concentrations. The between-run coefficient of variation over 107 days was 4.9%. The spiked serum sample analysis yielded recovery rates ranging from 98 to 102%. Enzyme immunochromatography was found to be a useful noninstrumented method for on-site testing. The test gives quantitative patient sample results comparable to the results obtained using established laboratory methods.

Adolescent↗
PubMed1992

Specific enzyme-multiplied immunoassay and fluorescence polarization immunoassay for cyclosporin compared with Cyclotrac [125I]radioimmunoassay.

The analysis of cyclosporin-A (CsA) has proved a valuable adjunct to clinical care of patients who have received organ grafts. The measurement of CsA in whole blood by specific methods has recently taken a new direction with the introduction of a range of rapid methods, including a homogeneous enzyme immunoassay technique (EMIT) and a monoclonal fluorescence polarization immunoassay (FPIA). The present paper compares these two methods with the established Cyclotrac specific [125I]RIA (radioimmunoassay) using both commercial CsA-spiked control material as well as a group of 60 patient specimens (predominantly renal transplants). While each of the new methods showed acceptable precision and accuracy with the commercial quality control material, significant differences were demonstrated with patient specimens, such that FPIA was 12.5% greater than [125I]RIA (p less than 0.0001), which was in turn 5.9% greater than EMIT (p = 0.007). These data suggested that the FPIA may have residual CsA-metabolite interference and that the EMIT method was the most "specific" for parent CsA of the three tested, potentially therefore more comparable to high-performance liquid chromatography (HPLC).

Antibodies, Monoclonal↗
PubMed1986

Comparison of particle-enhanced turbidimetric inhibition immunoassay and fluorescence polarization immunoassay using monoclonal antibodies for theophylline.

The DuPont theophylline assay reagent kit, a particle-enhanced turbidimetric inhibition immunoassay (PETINIA) method adapted for use on a centrifugal fast analyzer, was evaluated. It was compared with fluorescence polarization immunoassay (FPIA). Day-to-day precision was 4.7% at 6.8 micrograms/ml, and 3.3% at 26.6 micrograms/ml. The assay is linear to a concentration of 40 micrograms/ml. Good correlation was found between the two methods (PETINIA/FPIA: y = 1.04x + 0.15, r = 0.988, Syx = 1.19) in the evaluation of 176 patients receiving theophylline. This method offers a precise and accurate alternative to FPIA.

Animals↗
PubMed1999

Particle counting immunoassay for urinary cotinine. Comparison with chromatography, enzyme-linked immunoassay and fluorescence polarization immunoassay.

Urinary cotinine was measured according to its inhibitory activity on the agglutination of cotinine-coated latex particles by anti-cotinine antibodies, the agglutination being measured by optical counting of the remaining non-agglutinated particles (particle counting, PaC). The detection limit was 0.03 microgram/ml and the practical range extended from 0.03 to 3.9 micrograms/ml. The correlation results of 320 urine samples with those of high pressure liquid chromatography, enzyme-linked (Coti-Tracq EIA, Serex Inc., Maywood, NJ, USA), and fluorescence polarization immunoassay (TDX instrument, Abbott, Abbott Park, IL, USA) were r = 0.90, r = 0.69, r = 0.87, respectively, whereas the correlation coefficients between the assays other than particle counting ranged from 0.62 to 0.88. PaC does not require any separation step and can thus be easily automated.

Chromatography, High Pressure Liquid↗
PubMed1996

[Fluorescence polarization immunoassay and microparticle enzyme immunoassay].

We describe a new clinical laboratory instrument, the Abbott AxSYM, which provides random- and continuous-access testing for immunoassays, 20 onboard reagents, primary tube sampling, and a throughput of 80 to 120 tests per hour. The AxSYM incorporates three separate analytical technologies for processing immunoassays: microparticle enzyme immunoassay, fluorescence polarization immunoassay, and a novel technology known as ion-capture immunoassay. The system incorporates both common and technology-specific subsystems controlled by a real-time software scheduling processor. Tests can be processed in one- or two-step sandwich or competitive formats, with variable pipetting steps, incubation periods, optical read formats, and wash sequences. Menu capabilities include test for hepatitis, retrovirus, tumor markers, fertility markers, thyroid functions, and therapeutic drugs. The time to first result is 15 approximately 25 min for most routine assay and < or = 15 min for stat assays (i.e., creatine kinase MB isoenzyme, human chorionic gonadotropin beta subunit, and therapeutic drugs). AxSYM assay performance for 23 assays was comparable with that of the Abbott IMx and TDx analyzers; specimen correlation data had correlation from 0.99 to 1.10. Within-run imprecision (CV) was 1.5% to 11.4%, with most assays (19 of 23) demonstrating CVs < or = 8.0%.

Fluorescence Polarization Immunoassay↗
PubMed2003

Fluorescence polarization immunoassays for pesticides.

Fluorescence polarization immunoassay methods for the detection of pesticides and their metabolites or degradation products are reviewed. Advantages and limitations for application to pesticide detection in environmental and food samples are discussed. The influence of the structure of fluorescent-labeled tracers and the affinity and specificity of antibodies on analytical performance is examined. The methods are simple, readily automated, and rapid (total time for assay of a water sample is about 1 min) with sensitivity of 1 - 10 ng/ml pesticide in 0.01 - 0.1 ml sample.

Environmental Pollutants↗
PubMed1984

Laboratory evaluation of five assay methods for vancomycin: bioassay, high-pressure liquid chromatography, fluorescence polarization immunoassay, radioimmunoassay, and fluorescence immunoassay.

We compared the precision and accuracy of five methods used to measure the concentration of vancomycin in serum: bioassay, high-pressure liquid chromatography, fluorescence polarization immunoassay (FPIA [TDX; Abbott Laboratories, North Chicago, Ill.]), radioimmunoassay (RIA), and fluorescence immunoassay. Based on an analysis of seven standards and of 106 patient samples, all five methods were accurate, and four (bioassay, high-pressure liquid chromatography, FPIA, and RIA) were also precise. The FPIA was the most precise and the fluorescence immunoassay was the least precise of the methods tested; intrarun coefficients of variation for these two methods were 0.9 to 3.0% versus 8.9 to 14.5%, and interrun coefficients of variation were 2.8 to 8.1% versus 12.2 to 16.2%, respectively. The RIA was inconvenient because it required an extra dilution of the specimen being tested and an additional (64 micrograms/ml) vancomycin standard for specimens with 32 to 64 micrograms of vancomycin per ml. Based on its rapid turnaround time and the stability of its standard curve, we believe that the FPIA is the best method currently available to quantitate vancomycin in the clinical laboratory.

Biological Assay↗
PubMed1991

Clinical evaluation of teicoplanin fluorescence polarization immunoassay.

A teicoplanin fluorescence polarization immunoassay (FPIA) developed by International BioClinical (IBC) was evaluated by using serum samples from patients who had been receiving teicoplanin at Detroit Receiving Hospital (DRH) as part of a clinical investigation. Patient samples collected over a 1-year span were assayed at DRH and at IBC, and the results were compared with those of a standard microbiological assay performed at Merrell Dow Research Institute, Indianapolis, Ind. The FPIA has a rapid turnaround time (circa 20 min), utilizes small sample volumes (less than 100 microliters) and is sensitive and accurate in determining concentrations in the range of 5 to 100 micrograms/ml. The intra-assay and interassay coefficient of variation for controls (7, 35, and 75 micrograms/ml) was less than or equal to 13%. Concentrations greater than 100 micrograms/ml must be diluted prior to the assay, which may introduce additional error in determination. The FPIA compared well with the bioassay (r = 0.901) for 193 clinical samples. The results obtained utilizing the FPIA system were reproducible at two different sites, as illustrated by the high degree of correlation between the results at DRH and IBC (r = 0.92). There was less than 7% interference noted when teicoplanin was assayed in the presence of other antibiotics. Patient samples stored for up to 1 year retained their potency: the mean recovery rate in these samples was 107%. The FPIA should be useful for monitoring and adjusting teicoplanin dosage regimens in patients.

Anti-Bacterial Agents↗