Enzyme immunoassay of carbamazepine with a centrifugal analyzer.

1979 ◽  
Vol 25 (2) ◽  
pp. 295-298 ◽  
Author(s):  
D A Lacher ◽  
R Valdes ◽  
J Savory
Keyword(s):  
Enzyme Immunoassay ◽  
Sample Volume ◽  
Gas Liquid Chromatography ◽  
Good Precision ◽  
Concentration Data ◽  
Kinetic Rate ◽  
Analytical Recovery ◽  
Assay Time ◽  
Quantitative Results ◽  
Carbamazepine Concentration

Abstract We describe a rapid enzyme immunoassay for carbamazepine with a centrifugal analyzer (Rotochem IIA-36). Reagent costs are reduced fourfold while good precision and sensitivity are maintained. Sample volume is 10 microliter, and as many as 28 patients' sera can be measured during an assay time of 225 s. Assay temperature is 30 degrees C, the wavelength 340 nn. Linearity is excellent for a carbamazepine concentration range of 1 to 12 mg/L; analytical recovery is quantitative. Results correlate well with those by liquid- and gas-liquid chromatography. Absorbance rates for each carbamazepine concentration are acquired by a multi-point kinetic rate program and a computer program provides a logit-log transformation of absorbance rate vs. concentration data for final calculations in the assay. Hemoglobin interference precludes analysis of severely hemolyzed specimens.

Radioimmunoassay, enzyme immunoassay, spectrophotometry, and gas-liquid chromatography compared for determination of phenobarbital and diphenylhydantoin.

1976 ◽  
Vol 22 (6) ◽  
pp. 749-753
Author(s):  
V Spiehler ◽  
L Sun ◽  
D S Miyada ◽  
S G Sarandis ◽  
E R Walwick ◽  
...  
Keyword(s):  
Liquid Chromatography ◽  
Enzyme Immunoassay ◽  
Correlation Coefficients ◽  
Gas Liquid Chromatography ◽  
Ultraviolet Spectrophotometry ◽  
Epileptic Patients ◽  
Quantitative Results ◽  
Analytical Procedures

Abstract Sera from epileptic patients were assayed for phenobarbital and diphenylhydantoin by four different analytical procedures. Quantitative results obtained by radioimmunoassay (I) and enzyme immunoassay (II) were compared to each other and to the results obtained on aliquots of the same sample by gas-liquid chromatography (III) and ultraviolet spectrophotometry (IV). For phenobarbital the correlation coefficients were I vs. II, 0.909; I vs. III, 0.947; II vs. III, 0.917; I vs. IV, 0.950; II vs. IV, 0.953. For diphenylhydantoin the correlation coefficients were I vs. II, 0.953; I vs. III, 0.951; II vs. III, 0.957; I vs. IV, 0.862; II vs. IV, 0.898. The immunoassays can be substituted for liquid chromatography or ultraviolet spectrophotometry without changing the resulting clinical interpretations.

Radioimmunoassay, enzyme immunoassay, spectrophotometry, and gas-liquid chromatography compared for determination of phenobarbital and diphenylhydantoin.

1976 ◽  
Vol 22 (6) ◽  
pp. 749-753 ◽  
Author(s):  
V Spiehler ◽  
L Sun ◽  
D S Miyada ◽  
S G Sarandis ◽  
E R Walwick ◽  
...  
Keyword(s):  
Liquid Chromatography ◽  
Enzyme Immunoassay ◽  
Correlation Coefficients ◽  
Gas Liquid Chromatography ◽  
Ultraviolet Spectrophotometry ◽  
Epileptic Patients ◽  
Quantitative Results ◽  
Analytical Procedures

Abstract Sera from epileptic patients were assayed for phenobarbital and diphenylhydantoin by four different analytical procedures. Quantitative results obtained by radioimmunoassay (I) and enzyme immunoassay (II) were compared to each other and to the results obtained on aliquots of the same sample by gas-liquid chromatography (III) and ultraviolet spectrophotometry (IV). For phenobarbital the correlation coefficients were I vs. II, 0.909; I vs. III, 0.947; II vs. III, 0.917; I vs. IV, 0.950; II vs. IV, 0.953. For diphenylhydantoin the correlation coefficients were I vs. II, 0.953; I vs. III, 0.951; II vs. III, 0.957; I vs. IV, 0.862; II vs. IV, 0.898. The immunoassays can be substituted for liquid chromatography or ultraviolet spectrophotometry without changing the resulting clinical interpretations.

Enzyme immunoassay of thyroxin-binding globulin.

1982 ◽  
Vol 28 (12) ◽  
pp. 2408-2411 ◽  
Author(s):  
K Miyai ◽  
M Ito ◽  
N Hata
Keyword(s):  
Pregnant Women ◽  
Enzyme Immunoassay ◽  
Normal Subjects ◽  
Sample Volume ◽  
Coefficients Of Variation ◽  
Analytical Recovery ◽  
The Mean ◽  
Free Serum ◽  
Test Serum ◽  
Measurable Range

Abstract We describe a new double-antibody enzyme radioimmunoassay for thyroxin-binding globulin (TBG) in serum. A TBG-beta-D-galactosidase complex was prepared with m-maleimidobenzoyl N-hydroxysuccinimide ester. The mean analytical recovery of TBG added to serum was 99%, sample volume and TBG value were linearly related, and values for TBG determined by this method and those determined by radioimmunoassay correlated well (r = 0.98). Coefficients of variation averaged 7.6% within assay, 6.6% between assay. The measurable range of TBG in the serum was 3.3 to 52 mg/L, but higher TBG concentrations could be measured by diluting the test serum with TBG-free serum. Mean (and SD) serum TBG concentrations as determined by this method were as follows: for 20 normal subjects, 21.2 (3.7) mg/L; for 10 pregnant women, 50.1 (9.5 mg/L; and for 10 patients with TBG deficiency, not detectable.

Simultaneous enzyme immunoassay of two thyroid hormones.

1982 ◽  
Vol 28 (7) ◽  
pp. 1469-1473 ◽  
Author(s):  
C Blake ◽  
M N Al-Bassam ◽  
B J Gould ◽  
V Marks ◽  
J W Bridges ◽  
...  
Keyword(s):  
Thyroid Hormones ◽  
Enzyme Immunoassay ◽  
Sample Volume ◽  
Significant Advance ◽  
Assay Method ◽  
Reagent Cost ◽  
Assay Time ◽  
Catalyzed Reactions ◽  
Enzyme Labels ◽  
Beta Galactosidase

Abstract We describe an enzyme immunoassay in which the two thyroid hormones, triiodothyronine and thyroxin, are measured simultaneously in a single tube. The method involves labeling the two with separate enzymes (beta-galactosidase and alkaline phosphatase, respectively), whose catalyzed reactions can easily be distinguished from each other by absorption spectrophotometry, with o-nitrophenyl-beta-galactoside and phenolphthalein monophosphate as substrates. Performance of this dual assay method compares well with that of conventional single-hapten enzyme-labeled assays, and results compare well with those by two single-hapten radioimmunoassays. The dual assay has certain advantages over single-hapten methods: smaller sample volume, lower reagent cost, and shorter overall assay time. As presented here, the use of enzyme labels to measure two (or more) haptens simultaneously represents a significant advance in the use of immunoassay techniques.

scholarly journals The European Sero-Epidemiology Network: standardizing the enzyme immunoassay results for measles, mumps and rubella

2000 ◽  
Vol 125 (1) ◽  
pp. 127-143 ◽  
Author(s):  
N. ANDREWS ◽  
R. G. PEBODY ◽  
G. BERBERS ◽  
C. BLONDEAU ◽  
P. CROVARI ◽  
...  
Keyword(s):  
Enzyme Immunoassay ◽  
European Countries ◽  
Reference Laboratory ◽  
Sampling Methodology ◽  
Local Standard ◽  
Quantitative Results ◽  
Network Project ◽  
Reference Country

The ESEN (European Sero-Epidemiology Network) project was established to harmonize the seroepidemiology of five vaccine preventable infections including measles, mumps and rubella in eight European countries. This involved achieving comparability both in the assay results from testing in different centres and also sampling methodology. Standardization of enzyme immunoassay results was achieved through the development of common panels of sera by designated reference centres. The panels were tested at the reference laboratory and then distributed to each participating laboratory for testing using their routine methods. Standardization equations were calculated by regressing the quantitative results against those of the reference laboratory. Our study found large differences in unitage between participants, despite all using an EIA method standardized against an international or local standard. Moreover, our methodology adjusted for this difference. These standardization equations will be used to convert the results of main serosurvey testing into the reference country unitage to ensure inter-country comparability.

Solid-phase enzymoimmunoassay for osteocalcin in human serum or plasma, with use of a monoclonal antibody.

1989 ◽  
Vol 35 (10) ◽  
pp. 2087-2092 ◽  
Author(s):  
M J Power ◽  
P F Fottrell
Keyword(s):  
Monoclonal Antibody ◽  
Detection Limit ◽  
Horseradish Peroxidase ◽  
Human Serum ◽  
Solid Phase ◽  
Sample Volume ◽  
Microtiter Plates ◽  
Analytical Recovery ◽  
Peroxidase Conjugate

Abstract In this solid-phase enzymoimmunoassay on microtiter plates for osteocalcin in serum or plasma, we use an osteocalcin-horseradish-peroxidase conjugate and a monoclonal antibody raised against bovine osteocalcin. We thoroughly standardized the assay for measurement of osteocalcin in both serum and plasma, demonstrating independence of sample volume, and determining the analytical recovery and within-and between-assay CVs. The detection limit was between 0.6 and 1.1 micrograms/L and the ED50 was 16 micrograms/L for a 5-microL sample volume. The intra-assay CV over the range 3 to 74 micrograms/L was less than or equal to 15%. The interassay CV over the range 3.6 to 46 micrograms/L was less than or equal to 16%. Results by this assay and by an in-house radioimmunoassay in which the same monoclonal antibody was used correlated well (r2 = 0.948). Osteocalcin concentrations in serum and plasma as measured with the present assay agreed well with published values.

Homogeneous enzyme immunoassay for tobramycin evaluated and compared with a radioimmunoassay.

1982 ◽  
Vol 28 (6) ◽  
pp. 1370-1374 ◽  
Author(s):  
J Woo ◽  
M A Longley ◽  
D C Cannon
Keyword(s):  
Enzyme Immunoassay ◽  
Room Temperature ◽  
Correlation Study ◽  
Stability Study ◽  
Data Handling ◽  
Handling System ◽  
Analytical Recovery ◽  
Assay Precision ◽  
Absorbance Data ◽  
Homogeneous Enzyme Immunoassay

Abstract We evaluated a commercially available homogeneous enzyme immunoassay (EMIT, Syva Co.) for tobramycin against a reference radioimmunoassay (RIA) method. Between-assay precision (CV) was 2.9% at 6.2 mg/L and 3.0% for values in the range of 1.0-7.6 mg/L. Accuracy based on a recovery experiment (1.0-13.0 mg/L) yielded an analytical recovery of 88-112%. A correlation study with 75 sera from patients on tobramycin therapy showed that EMIT = 0.984 RIA - 0.0808, r = 0.993. Neither the EMIT nor the RIA procedure was affected by the presence of gentamicin, amikacin, and vancomycin. Absorbance data from the EMIT system calculated with the conventional RIA logit-log algorithm correlate well with results generated by the Syva data-handling system (logit-log = 1.077 Syva - 0.318, r = 0.998). A reagent stability study indicated that the EMIT reagents, once reconstituted, remain stable for at least 17 days when stored at refrigerated temperatures, or 11 days if stored at room temperature, thus enabling frequent "stat" assays without the need to prepare a calibration curve each time.

Radioreceptor Assay for Quantifying FK-506 Immunosuppressant in Whole Blood

1992 ◽  
Vol 38 (7) ◽  
pp. 1307-1310 ◽  
Author(s):  
J N Murthy ◽  
Y Chen ◽  
V S Warty ◽  
R Venkataramanan ◽  
J G Donnelly ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Enzyme Immunoassay ◽  
Whole Blood ◽  
Binding Protein ◽  
Radioreceptor Assay ◽  
Fk 506 ◽  
Blood Concentrations ◽  
Chromatographic Columns ◽  
Analytical Recovery

Abstract We describe a quantitative radioreceptor assay (RRA) for quantifying FK-506 in whole blood. FK-506 extracted from whole blood with a cyclohexyl-sorbent column competes with [3H]dihydro-FK-506 for binding to a partially purified preparation of FK-506 binding protein (FK-BP). Free and protein-bound FK-506 are separated on LH 20 Sephadex chromatographic columns. We compared the results of this method with those of an enzyme immunoassay that uses a monoclonal antibody: r = 0.97, Sy/x = 0.039. Between-day precisions (CV) at FK-506 concentrations of 8 and 17 micrograms/L were 9.2% and 8.2%, respectively. Within-run precisions were 5.9%, 8.1%, and 9.4%, respectively, at 4, 8, and 15 micrograms/L. Analytical recovery, evaluated at 5, 10, 15, 20, and 25 micrograms/L for FK-506 added to whole blood, ranged from 98% to 103%. The assay can reliably quantify FK-506 blood concentrations between 1.0 and 25 micrograms/L.

Homogeneous enzyme immunoassay for cortisol with a centrifugal analyzer.

1984 ◽  
Vol 30 (11) ◽  
pp. 1824-1826 ◽  
Author(s):  
J M Izquierdo ◽  
A Quirós ◽  
J Alvarez-Uría ◽  
P Sotorrío
Keyword(s):  
Enzyme Immunoassay ◽  
Protein Complex ◽  
Acidic Solution ◽  
Serum Cortisol ◽  
Standard Curve ◽  
Analytical Recovery ◽  
Target Values ◽  
Assay Precision ◽  
Homogeneous Enzyme Immunoassay ◽  
Control Samples

Abstract We determine serum cortisol by a homogeneous enzyme immunoassay in the Cobas Bio centrifugal analyzer. To unbind cortisol from its protein complex, serum is treated for 15 min with an acidic solution. The reaction then proceeds automatically in the analyzer at 37 degrees C. To 50 microL of sample mixture is added 125 microL of reagent (cortisol antibodies, glucose 6-phosphate, and NAD+). This mixture is incubated for 60 s, after which 25 microL of a cortisol derivative labeled with glucose 6-phosphate is added; the increase in absorbance is monitored at 340 nm. The standard curve was linear from 10 to 500 micrograms of cortisol per liter. Within-assay precision (CV) varied from 0.2 to 0.6%, between-assay precision from 6.2 to 10.6%. Analytical recovery ranged from 100 to 103%. Results for control samples deviated from target values by 1.4 to 7.8%. Results compared well with those by radioimmunoassay. The method is reliable and practicable and will usefully replace previous routine methods for serum cortisol.

Adaptation of "EMIT" technique for serum phenobarbital and diphenylhydantoin assays to the miniature centrifugal analyzer.

1976 ◽  
Vol 22 (6) ◽  
pp. 905-907 ◽  
Author(s):  
S D Brunk ◽  
T P Hadjiioannou ◽  
S I Hadjiioannou ◽  
H V Malmstadt
Keyword(s):  
Gas Chromatography ◽  
Enzyme Immunoassay ◽  
Reaction Rates ◽  
Anticonvulsant Drugs ◽  
Rate Measurement ◽  
Serum Samples ◽  
Analytical Recovery ◽  
Reagent Cost ◽  
Measurement Mode ◽  
Multiple Samples

Abstract We used a miniature centrifugal analyzer in a spectrophotometric rate-measurement mode to determine the anticonvulsant drugs phenobarbital and diphenylhydantoin in serum, by use of a modified enzyme immunoassay ("EMIT", Syva Corp.) We decreased reagent cost per determination by at least sixfold by means of microscale techniques. Also, the analysis rate is increased by measuring multiple samples simultaneously. Our method requires only 3 mul of serum for duplicate determinations. Replicate analyses of sera containing phenobarbital and diphenylhydantoin gave reaction rates with a CV of 1.5%. Run-to-run CV was 15%. Analytical recovery for drug-supplemented serum samples was 98%, and results for a series of samples compared well with results obtained by gas chromatography (for phenobarbital, r = 0.95; for diphenylhydantoin, r = 0.91).

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