Variability among commercially available digoxin radioimmunoassay kits in cross reactivity to dihydrodigoxin.

1978 ◽  
Vol 24 (1) ◽  
pp. 155-157 ◽  
Author(s):  
W G Kramer ◽  
N L Kinnear ◽  
H K Morgan
Keyword(s):  
Human Serum ◽  
Therapeutic Range ◽  
Cross Reactivity ◽  
Serum Samples ◽  
Serum Digoxin ◽  
The Cross ◽  
High Degree ◽  
Free Serum ◽  
Digoxin Radioimmunoassay

Abstract We evaluated four commercially available 125I-digoxin radioimmunoassay kits with regard to their ability to cross react with the digoxin metabolite dehydrodigoxin. We prepared dihydrodigoxin serum samples in digoxin-free serum over the concentration range 0.4 to 5.0 microgram/liter and assayed them with each kit according to the manufacturer's instructions. The metabolite was able to displace the 125I-labeled digoxin derivative from the antibody supplied with all four kits. However, the extent of the cross reactivity depended on the kit, ranging from essentially zero to a high degree of interference. Dihydrodigoxin is the only metabolite of digoxin to have been quantitiated in human serum, and may comprise up to 30% of total glycosides. Over the clinical and therapeutic range of serum digoxin concentrations, enough dihydrodigoxin can be produced to interfere in the determination of serum digoxin concentrations by this method. We suggest that laboratories evaluate their specific kit with regard to cross reactivity to this metabolite.

Cross reactivity of digitoxin and spironolactone in two radioimmunoassays for serum digoxin.

1978 ◽  
Vol 24 (4) ◽  
pp. 706-709 ◽  
Author(s):  
H Müller ◽  
H Bräuer ◽  
B Resch
Keyword(s):  
Oral Administration ◽  
Solid Phase ◽  
Cross Reactivity ◽  
Serum Digoxin ◽  
The Cross ◽  
Oral Doses ◽  
Digoxin Radioimmunoassay

Abstract We measured the cross reactivity of two medications--digitoxin and spironolactone--in two digoxin radioimmunoassay (liquid and solid-phase) kit procedures. Both tests showed similar average percentages of cross reactivity with digitoxin (7.2 and 8.9% for intravenous, and 11.9 and 10.9% for oral administration), but no cross reactivity with spironolactone or its metabolites after equal intravenous or oral doses.

Simultaneous Determination of Chloroquine and Pyrimethamine with Cetirizine in an Active Form and Human Serum by RP-HPLC

2021 ◽  
Author(s):  
Hina Shamshad ◽  
Ali Sayqal ◽  
Jahan Zeb ◽  
Agha Zeeshan Mirza
Keyword(s):  
Human Serum ◽  
Simultaneous Determination ◽  
Active Form ◽  
Internal Standard ◽  
Hplc Method ◽  
Serum Samples ◽  
Rp Hplc ◽  
Cetirizine Hydrochloride ◽  
Bulk Drug

Abstract A simple, accurate and precise RP-HPLC method was developed for the simultaneous determination of chloroquine, pyrimethamine and cetirizine hydrochloride concentrations in bulk drug and human serum. The assay was performed using a mobile phase of methanol: water (70:30) at pH of 2.8 ± 0.05 on the Purospher C-18 column with UV detection at 230 nm and rosuvastatin used as an internal standard. The retention times observed for chloroquine, pyrimethamine and cetirizine hydrochloride were 3.5, 2.5 and 5.5 minutes, respectively. The method was found to be specific for the assayed drugs showing a linear response in the concentration range of 1–100 μg mL−1 with coefficients of determination values of (r = 0.999). The method was developed and validated according to ICH guidelines. The method was used to monitor the serum samples and was found to be sensitive for therapeutic purposes, showing the potential to be a useful tool for routine analysis in laboratories.

Simultaneous determination of ascorbic and uric acids and dopamine in human serum samples using three-way calibration with data from square wave voltammetry

2016 ◽  
Vol 129 ◽  
pp. 205-212 ◽  
Author(s):  
Adrian Marcelo Granero ◽  
Gastón Darío Pierini ◽  
Sebastián Noel Robledo ◽  
María Susana Di Nezio ◽  
Héctor Fernández ◽  
...  
Keyword(s):  
Human Serum ◽  
Simultaneous Determination ◽  
Square Wave Voltammetry ◽  
Serum Samples ◽  
Square Wave ◽  
Human Serum Samples ◽  
Wave Voltammetry

scholarly journals Conductimetric Biosensor for the Detection of Uric Acid by Immobilization Uricase on Nata de Coco Membrane—Pt Electrode

2011 ◽  
Vol 6 ◽  
pp. ACI.S7346 ◽  
Author(s):  
Ani Mulyasuryani ◽  
Arie Srihardiastutie
Keyword(s):  
Uric Acid ◽  
Human Serum ◽  
Candida Utilis ◽  
Medical Laboratory ◽  
Membrane Thickness ◽  
Serum Samples ◽  
Ph Change ◽  
Pt Electrode ◽  
Enzyme Biosensor

A conductimetric enzyme biosensor for uric acid detection has been developed. The uricase, as enzyme, is isolated from Candida utilis and immobilized on a nata de coco membrane-Pt electrode. The biosensor demonstrates a linear response to urate over the concentration range 1-6 ppm and has good selectivity properties. The response is affected by the membrane thickness and pH change in the range 7.5-9.5. The response time is three minutes in aqueous solutions and in human serum samples. Application of the biosensor to the determination of uric acid in human serum gave results that compared favourably with those obtained by medical laboratory. The operational stability of the biosensor was not less than three days and the relative error is smaller than 10%.

Determination of ciprofloxacin and enoxacin in human serum samples by micellar liquid chromatography

2004 ◽  
Vol 516 (1-2) ◽  
pp. 135-140 ◽  
Author(s):  
José Luis Vı́lchez ◽  
Lilia Araujo ◽  
Avismelsi Prieto ◽  
Alberto Navalón
Keyword(s):  
Liquid Chromatography ◽  
Human Serum ◽  
Micellar Liquid Chromatography ◽  
Serum Samples ◽  
Human Serum Samples

Reduced variation of tracer binding in digoxin radioimmunoassay by use of (125I)-labeled tyrosine-methyl-ester derivative: relation of thyroxine concentration to binding.

1976 ◽  
Vol 22 (10) ◽  
pp. 1732-1734 ◽  
Author(s):  
B H Kroening ◽  
M Weintraub
Keyword(s):  
Methyl Ester ◽  
Binding Proteins ◽  
Serum Samples ◽  
Methyl Ester Derivative ◽  
Ester Derivative ◽  
Free Serum ◽  
Digoxin Radioimmunoassay

Abstract Between-sample variation in tracer binding in the 125I-labeled digoxin radioimmunoassay was investigated with two tracers, 3-O-succinyl-digoxigenin-[125I]-labeled tyrosine and [125I]-labeled tyrosine-methyl-ester-digoxin. Digoxin-free serum samples having various concentrations of thyroxine were assayed with both tracers. The percentage of tracer bound when the samples were assayed with the first-mentioned tracer was increased significantly for the low thyroxine groups when compared to the normal (P less than 0.001) or the high thyroxine groups (P less than 0.05). Little difference existed when the latter tracer was used. There was variation in tracer binding when serum from dogs dosed with thyrotropin was assayed with the first tracer, but there was little variation with the second. Tracer binding may be influenced by thyroxine-binding proteins. Variation in tracer binding appears to be reduced when [125I]-labeled tyrosine-methyl-ester-digoxin is used.

P0301FIT FOR PURPOSE VALIDATION OF A CLINICAL ASSAY FOR THE DETECTION OF SERUM LEVELS OF GALACTOSE-DEFICIENT IMMUNOGLOBULIN A1 (GD-IGA1) IN PATIENTS WITH IGA NEPHROPATHY (IGAN)

2020 ◽  
Vol 35 (Supplement_3) ◽  
Author(s):  
Laura Sponton ◽  
Hulin Jin ◽  
Markus Fluck ◽  
Yusuke Suzuki ◽  
Amy Kao
Keyword(s):  
Quantitative Determination ◽  
Human Serum ◽  
Iga Nephropathy ◽  
Calibration Curve ◽  
Clinical Studies ◽  
Serum Samples ◽  
Freeze Thaw ◽  
Healthy Donors ◽  
Validation Parameters

Abstract Background and Aims Analysis of serum or plasma from patients with IgA nephropathy (IgAN) has confirmed the presence of elevated levels of circulating immune complexes containing Gd-IgA1 (Czerkinsky 1986). New sensitive and reasonably specific noninvasive tests are emerging to guide the therapeutic strategy that is applicable to all stages of IgAN (Suzuki 2014). Here we are reporting the fit for purpose validation of an ELISA method for the quantitative determination of Gd-IgA1 in human serum samples to support biomarker investigations in clinical studies of Merck KGaA, Darmstadt. Method The assay was developed based on a commercially available immunoassay kit. The dynamic range of the calibration curve was determined from 1.56 ng/mL (LLOQ) to 100 ng/mL (ULOQ). With a minimum required dilution of 200-fold and standard assay volume of 50.0 μL, the range of the method in matrix was from 312 ng/mL to 20, 000 ng/mL. In assay validation phase, multiple validation parameters were evaluated, which included minimum required dilution (MRD), calibration curve, matrix effect, Intra- & Inter run accuracy & precision, selectivity, and parallelism. Additional validation parameters include sample stability (short/long term, freeze-thaw) and batch-to-batch comparison. Results All samples measured for intra & Inter - assay precision, accuracy, fulfilled the specifications according to the acceptance criteria. The selectivity was assessed using blank serum matrix from 10 individuals: the result indicated that matrix components in serum did not interfere with the detection of Gd-IgA1. Parallelism assessment was performed successfully for both samples from healthy donors and IgAN patient samples up to dilution factor (DF) 3200 (serum samples from healthy donors were determined up to DF 1600). All DF-corrected results within the assay range were determined with %CV ≤ 30.0%. Batch to batch comparison was assessed successfully based on the known shelf life of the kit. Short term stability using QC samples were given for up to 24hrs at room temperature. Freeze-thaw stability was given for up to 3 cycles at -20°C±5°C and -75°C±15°C. The investigations were performed according to general guidelines for method validation and applicable regulations. The results of investigated validation parameters fulfilled the requirements and recommendations, generally accepted for bioanalytical projects. Conclusion The present validation qualified the method for the quantitative determination of Gd-IgA1 in human serum samples from clinical studies.

scholarly journals Characterization of cardiac troponin subunit release into serum after acute myocardial infarction and comparison of assays for troponin T and I

1998 ◽  
Vol 44 (6) ◽  
pp. 1198-1208 ◽  
Author(s):  
Alan H B Wu ◽  
Yue-Jin Feng ◽  
Robert Moore ◽  
Fred S Apple ◽  
Paul H McPherson ◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
Acute Myocardial Infarction ◽  
Cardiac Troponin ◽  
Troponin I ◽  
Troponin T ◽  
Cross Reactivity ◽  
Binary Complex ◽  
Serum Samples ◽  
Binary And Ternary Complexes ◽  
The Cross

Abstract We examined the release of cardiac troponin T (cTnT) and I (cTnI) into the blood of patients after acute myocardial infarction (AMI). Three postAMI serum samples were applied in separate analytical runs onto a calibrated gel filtration column (Sephacryl S-200), and the proteins were separated by molecular weight. Using commercial cTnT and cTnI assays measured on collected fractions, we found that troponin was released into blood as a ternary complex of cTnT-I-C, a binary complex of cTnI-C, and free cTnT, with no free cTnI within the limits of the analytical methodologies. The serum samples were also examined after incubation with EDTA and heparin. EDTA broke up troponin complexes into individual subunits, whereas heparin had no effect on the assays tested. We added free cTnC subunits to 24 AMI serum samples and found no marked increase in the total cTnI concentrations, using an immunoassay that gave higher values for the cTnI-C complex than free cTnI. To characterize the cross-reactivity of cTnT and cTnI assays, purified troponin standards in nine different forms were prepared, added to serum and plasma pools, and tested in nine quantitative commercial and pre-market assays for cTnI and one approved assay for cTnT. All nine cTnI assays recognized each of the troponin I forms (complexed and free). In five of these assays, the relative responses for cTnI were nearly equimolar. For the remainder, the response was substantially greater for complexed cTnI than for free cTnI. Moreover, there was a substantial difference in the absolute concentration of results between cTnI assays. The commercial cTnT assay recognized binary and ternary complexes of troponin on a near equimolar basis. We conclude that all assays are useful for detection of cardiac injury. However, there are differences in absolute cTnI results due to a lack of mass standardization and heterogeneity in the cross-reactivities of antibodies to various troponin I forms.

scholarly journals Direct Injection Liquid Chromatographic Technique for Simultaneous Determination of Two Antihistaminic Drugs and Their Main Metabolites in Serum

2007 ◽  
Vol 90 (2) ◽  
pp. 384-390 ◽  
Author(s):  
Samy Emara ◽  
Alaa El-Gindy ◽  
Mostafa K Mesbah ◽  
Ghada M Hadad
Keyword(s):  
Human Serum ◽  
Simultaneous Determination ◽  
Chromatographic Technique ◽  
Simple Liquid ◽  
Good Precision ◽  
Active Metabolites ◽  
Serum Samples ◽  
Antihistaminic Drugs ◽  
Liquid Chromatographic

Abstract A very simple liquid chromatographic technique was developed and validated for the simultaneous determination of 2 antihistaminic drugs, loratadine (LT) and terfenadine (TR), and their major active metabolites, desloratadine (DL) and fexofenadine (FX), respectively, in human serum. LT, DL, TR, and FX from directly injected serum samples were enriched on a protein-coated RP8 silica precolumn (10 4.6 mm id) while serum constituents, such as proteins and salts, were eluted to waste. Using an online column-switching system, the drugs and their metabolites were quantitatively transferred and separated on a second analytical column (Shim-pack 5 μm particle size cyanopropyl, 250 × 4.6 mm id) followed by ultraviolet detection at 243 nm for LT and DL and 220 nm for TR and FX. Very good precision, accuracy, and linearity were obtained over the range of 101000 ng/mL for LT and DL, 10500 ng/mL for TR, and 103000 ng/mL for FX in human serum. High extraction recoveries from serum ranging from 96.03 to 98.19, 95.44 to 97.26, 95.61 to 98.17, and 95.60 to 97.89 for LT, DL, TR, and FX, respectively, were obtained.

Radioimmunoassay of creatine kinase isoenzymes in human serum: isoenzyme BB.

1978 ◽  
Vol 24 (3) ◽  
pp. 422-428 ◽  
Author(s):  
M H Zweig ◽  
A C Van Steirteghem ◽  
A N Schechter
Keyword(s):  
Creatine Kinase ◽  
Human Serum ◽  
Cross Reactivity ◽  
Healthy Adults ◽  
Serum Samples ◽  
Creatine Kinase Isoenzymes ◽  
Specific Radioimmunoassay ◽  
Assay Precision ◽  
Free Antigen ◽  
Healthy Persons

Abstract We describe a sensitive, specific radioimmunoassay for the BB isoenzyme of creatine kinase (CK-BB) in serum. A sequential saturation assay was used to achieve sufficient sensitivity to detect the isoenzyme in 100-microliter serum samples of all healthy persons and patients tested. Bound and free antigen were separated by a second antibody system. Large excesses of purified isoenzyme MM did not react in the assay. Cross reactivity of two preparations of CK-MB was only 1 to 7+. The 95th percentile of serum CK-BB in 208 healthy adults was 6.2 microgram/liter. Within-assay and between-assay precision ranged from 5.5 to 11.9% and 9.7 to 13.6%, respectively.

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