Fluorescence polarization immunoassay of urinary vanillylmandelic acid

1990 ◽  
Vol 36 (1) ◽  
pp. 110-112 ◽  
Author(s):  
G W Mellor ◽  
G Gallacher
Keyword(s):  
Urine Sample ◽  
Fluorescence Polarization ◽  
Minimum Detectable Concentration ◽  
Vanillylmandelic Acid ◽  
Fluorescence Polarization Immunoassay ◽  
Standard Curve ◽  
Analytical Recovery ◽  
Detectable Concentration ◽  
Hydroxyindoleacetic Acid ◽  
Neural Crest Tumors

Abstract This rapid fluorescence polarization immunoassay for urinary vanillylmandelic acid (VMA) involves use of our previously described antiserum and label and the program for 5-hydroxyindoleacetic acid in the Abbott TDx fluorimeter. Urine samples were measured directly, without pretreatment. The minimum detectable concentration was 0.3 mg/L, and the range of the standard curve was 0.3-200.0 mg/L. Precision, analytical recovery, and correlation of results with those by the Pisano method (Clin Chim Acta 1962;7:285-91) were all satisfactory. With this procedure one can determine the VMA concentration in 10 urine sample in 22 min. This is the first report of a clinical immunoassay for VMA and should greatly simplify screening for neural crest tumors.

Competitive particle concentration fluorescence immunoassay for measuring 5,10-dideaza-5,6,7,8-tetrahydrofolic acid (lometrexol) in serum

1991 ◽  
Vol 37 (2) ◽  
pp. 254-260 ◽  
Author(s):  
Larry D Taber ◽  
Peter O'Brien ◽  
Ronald R Bowsher ◽  
J Richard Sportsman
Keyword(s):  
Particle Concentration ◽  
Cross Reactivity ◽  
Minimum Detectable Concentration ◽  
Fluorescence Immunoassay ◽  
Standard Curve ◽  
Coefficients Of Variation ◽  
Analytical Recovery ◽  
Detectable Concentration ◽  
Tetrahydrofolic Acid ◽  
Cancer Agent

Abstract A competitive particle concentration fluorescence immunoassay (PCFIA) is described for measuring 5,10-dideaza-5,6,7,8-tetrahydrofolic acid (lometrexol; Lilly) in human serum. b-Phycoerythrin-labeled lometrexol competes with free lometrexol for binding to a limiting concentration of lometrexol-specific antibodies immobilized by a second antibody to submicrometer-diameter polystyrene particles in specially designed 96-well plates. Reaction particles are washed and concentrated onto filter membranes in the wells of the plates and the fluorescence is measured at 575 nm. The method, including sample preparation and data reduction, is automated and can be completed in less than 2 h. The assay has a standard curve maximum measurable concentration of 1000 micrograms/L and a minimum detectable concentration of 0.1 microgram/L. Analytical recovery of lometrexol in serum is quantitative at concentrations greater than 1 micrograms/L. Intra- and interassay coefficients of variation at 50 micrograms/L in serum are 7.1% (n = 9) and 7.5% (n = 33), respectively. The cross-reactivity of naturally occurring folates, folic acid analogs, and the anti-cancer agent methotrexate is minimal. We report the use of the PCFIA during Phase I clinical studies designed to evaluate the pharmacokinetics of lomextrexol after intravenous administration to cancer patients.

Digoxin-like immunoreactivity eliminated from serum by centrifugal ultrafiltration before fluorescence polarization immunoassay of digoxin.

1987 ◽  
Vol 33 (4) ◽  
pp. 606-608 ◽  
Author(s):  
R H Christenson ◽  
S D Studenberg ◽  
S Beck-Davis ◽  
F A Sedor
Keyword(s):  
Fluorescence Polarization ◽  
Renal Dialysis ◽  
Fluorescence Polarization Immunoassay ◽  
Dialysis Patients ◽  
Sulfosalicylic Acid ◽  
Blood Samples ◽  
Assay Procedure ◽  
Analytical Recovery ◽  
Endogenous Compounds ◽  
Centrifugal Ultrafiltration

Abstract Digoxin determined in the Abbott "TDx" by fluorescence polarization immunoassay by the manufacturer's recommended method involving precipitation of protein with 5-sulfosalicylic acid (SSA) is subject to interference from endogenous compounds having digoxin-like immunoreactivity. Guided by the work of Graves et al. (Clin Chem 1986;32:1506-9), we eliminated interference caused by digoxin-like immunoreactivity by substituting ultrafiltration for precipitation with SSA to remove protein. Using the manufacturer's method, we quantified digoxin in serum from 53 patients in three clinically defined groups who were receiving no digoxin, finding apparent digoxin in excess of the 200 ng/L detection limit in 24% of the 17 pregnant women, 59% of the 17 renal-dialysis patients, and all of 19 neonatal cord-blood samples examined. No measurable digoxin immunoreactivity was observed by fluorescence polarization immunoassay for any of the 53 clinically defined patients after removal of protein by ultrafiltration. For 22 men for whom digoxin was prescribed, digoxin measurement after protein removal by SSA and by ultrafiltration correlated well (r = 0.98), with good proportionality (slope = 1.04). Analytical recovery of added digoxin from adulterated serum was 115% after SSA, but 100% after ultrafiltration. Thus, before this assay procedure, we recommend ultrafiltration, to remove digoxin-like interference.

Colorimetry of hemoglobin in plasma with 2,2'-azino-di(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS).

1984 ◽  
Vol 30 (3) ◽  
pp. 357-359 ◽  
Author(s):  
M Takayanagi ◽  
T Yashiro
Keyword(s):  
Hydrogen Peroxide ◽  
Calibration Curve ◽  
Plasma Proteins ◽  
Sulfonic Acid ◽  
Minimum Detectable Concentration ◽  
Colored Form ◽  
Analytical Recovery ◽  
Detectable Concentration ◽  
Precision And Accuracy

Abstract Hemoglobin in plasma can be determined by the color-developing action of 2,2'-azino-di(3-ethylbenzthiazoline-6-sulfonic acid), which is oxidized to a colored form by a peroxidase-like effect of hemoglobin in the presence of hydrogen peroxide. Sensitivity, precision, and accuracy are discussed. The calibration curve is linear for hemoglobin concentrations up to 1 g/L; the minimum detectable concentration is 20 mg/L. The within-run precision (CV) was 2.39%, analytical recovery 101.8%. Interference from plasma proteins and lipids was eliminated by centrifuging the reaction mixture before measuring its absorbance at 410 nm.

Simultaneous liquid-chromatographic determination of urinary vanillylmandelic acid, homovanillic acid, and 5-hydroxyindoleacetic acid.

1988 ◽  
Vol 34 (12) ◽  
pp. 2504-2506 ◽  
Author(s):  
A Gironi ◽  
G Seghieri ◽  
M Niccolai ◽  
P Mammini
Keyword(s):  
Homovanillic Acid ◽  
Clinical Laboratory ◽  
Chromatographic Determination ◽  
Gradient Elution ◽  
Vanillylmandelic Acid ◽  
Liquid Chromatographic Method ◽  
Analytical Recovery ◽  
Hydroxyindoleacetic Acid ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract We describe a liquid-chromatographic method for quantifying, simultaneously by a single procedure, vanillylmandelic acid (VMA), homovanillic acid (HVA), and 5-hydroxyindoleacetic acid (5-HIAA) in urine. After solvent extraction of acidified urine, the analytes were chromatographed on a C8 column, with use of a mobile phase of phosphate buffer (20 mmol/L, pH 4.0) and methanol with a variable gradient elution, and detected fluorometrically. We report the analytical recovery, sensitivity, precision, working linear range, and potential for interference from similar molecules or drugs. The results of such tests demonstrate that the proposed method is sensitive and reproducible. It is, furthermore, easy to perform, and thus is suitable for use in the clinical laboratory.

Radioimmunoassay of serotonin (5-hydroxytryptamine) in cerebrospinal fluid, plasma, and serum.

1982 ◽  
Vol 28 (4) ◽  
pp. 624-628 ◽  
Author(s):  
F Engbaek ◽  
B Voldby
Keyword(s):  
Cerebrospinal Fluid ◽  
Polyethylene Glycol ◽  
Normal Subjects ◽  
Minimum Detectable Concentration ◽  
Minimum Concentration ◽  
Bovine Albumin ◽  
Platelet Poor Plasma ◽  
Detectable Concentration ◽  
Disc Herniations ◽  
Hydroxyindoleacetic Acid

Abstract We describe a direct radioimmunoassay for serotonin (5-hydroxytryptamine) in cerebrospinal fluid, platelet-poor plasma, and serum. We raised antisera in rabbits against serotonin diazotized to a conjugate of bovine albumin and D,L-p-aminophenylalanine. Polyethylene glycol, alone or in combination with anti-rabbit immunoglobulins, is used to separate bound and unbound tritiated serotonin. The minimum concentration of serotonin detectable is 2 nmol/L in a 200-microL sample. Within-day precision (CV) is 4.3%, between-day precision 7.7%. Analytical recoveries of serotonin are 109% and 101% for cerebrospinal fluid and plasma, respectively. Tryptophan, 5-hydroxytryptophan, 5-hydroxyindoleacetic acid, and 5-hydroxytryptophol do not interfere with the assay. However, 5-methoxytryptamine and tryptamine cross react. Of samples of cerebrospinal fluid from patients with disc herniations (n = 21) or low-pressure hydrocephalus (n = 10), one-third had concentrations of 2-4 nmol/L and two-thirds were below the minimum detectable concentration. The observed range for the concentration of serotonin in plasma of 14 normal subjects was 5-14 nmol/L (mean +/- SD, 9 +/- 3 nmol/L). The observed ranges for serotonin in serum were: for 10 women 520-900 (mean +/- SD: 695 +/- 110) nmol/L and for 10 men 380-680 (520 +/- 94) nmol/L.

Fluorescence polarization immunoassay of gentamicin or netilmicin in blood spotted on filter paper.

1989 ◽  
Vol 35 (5) ◽  
pp. 867-869 ◽  
Author(s):  
T Fujimoto ◽  
Y Tsuda ◽  
R Tawa ◽  
S Hirose
Keyword(s):  
Filter Paper ◽  
Fluorescence Polarization ◽  
Newborn Infants ◽  
Dried Blood Spots ◽  
Blood Collection ◽  
Fluorescence Polarization Immunoassay ◽  
Simple Method ◽  
Small Children ◽  
Analytical Recovery

Abstract In this improved simple method for determination of aminoglycoside antibiotics in dried-blood spots on filter paper, gentamicin or netilmicin is recovered from the blood spot most effectively by incubation for 60 min in an ultrafiltration tube containing 500 microL of 0.5 mol/L Na2HPO4 buffer. The eluates from the paper are centrifuged, then transferred to an Abbott TDx cartridge for measurement of gentamicin or netilmicin by fluorescence polarization immunoassay. The dried sample on paper is stable for about eight days at ambient temperature. Intra-assay CVs for gentamicin and netilmicin are less than 8.5% and less than 6.1%, respectively. Analytical recovery of gentamicin and netilmicin from the paper exceeded 90%. This method permits simple blood collection and monitoring of the therapeutic concentration of gentamicin or netilmicin in serum, particularly that of newborn infants and small children.

Fluorescence polarization immunoassay for ethosuximide evaluated and compared with two other immunoassay techniques.

1986 ◽  
Vol 32 (9) ◽  
pp. 1781-1783 ◽  
Author(s):  
C F Stewart ◽  
M B Bottorff
Keyword(s):  
Fluorescence Polarization ◽  
Coefficient Of Determination ◽  
Plasma Samples ◽  
Fluorescence Polarization Immunoassay ◽  
Standard Curve

Abstract We evaluated a new fluorescence polarization immunoassay (FPIA) for ethosuximide in the Abbott TDx and compared results with those by two other ethosuximide immunoassays, EMIT (Syva Co.) and aca (DuPont). The FPIA assay produced within- and between-day CVs of less than 5% at the low, medium, and high ranges of the standard curve. For the ethosuximide FPIA assay the standard curve was stable during the 47 days of the study. By all three methods, we analyzed 100 serum and plasma samples from patients who were receiving ethosuximide. The coefficient of determination (r2) for TDx versus EMIT was 0.973 (slope, 0.96; intercept, -0.80); for TDx vs aca it was 0.985 (slope, 1.00; intercept, -2.44); both relationships were statistically significant (p less than 0.05). Values for patient's specimens were significantly lower by the TDx than by the aca or EMIT methods (p less than 0.05).

Pentobarbital quantification in the presence of phenobarbital by fluorescence polarization immunoassay

1991 ◽  
Vol 37 (10) ◽  
pp. 1774-1777 ◽  
Author(s):  
R Earl ◽  
L Sobeski ◽  
D Timko ◽  
R Markin
Keyword(s):  
Sodium Hydroxide ◽  
Fluorescence Polarization ◽  
Fluorescence Polarization Immunoassay ◽  
Alkali Pretreatment ◽  
Short Acting ◽  
Analytical Recovery ◽  
Long Acting

Abstract We developed a method for measuring pentobarbital in samples that also contain phenobarbital. The phenobarbital is destroyed by adding sodium hydroxide and then heating at 95 degrees C for 60 min. Pentobarbital is not affected by this pretreatment and can then be measured with an Abbott TDx barbiturates kit. Using this method, we obtained an average analytical recovery of 98% of added pentobarbital and a correlation of y = 0.953x + 3.4 vs HPLC. The intra-assay CV was 3.7% at 25.8 mg/L; the interassay CV was 6.2% at 16.1 mg/L. Other long-acting barbiturates, e.g., hexobarbital, are also effectively destroyed by this alkali pretreatment. Other short-acting barbiturates, e.g., secobarbital, are not removed and would produce an interference.

Intercomparison of seven radioimmunoassay kits and a fluorescence polarization immunoassay kit for digoxin.

1984 ◽  
Vol 30 (7) ◽  
pp. 1225-1227 ◽  
Author(s):  
K A Erickson ◽  
P J Green
Keyword(s):  
Fluorescence Polarization ◽  
Correlation Coefficients ◽  
The Other ◽  
Analysis Time ◽  
Fluorescence Polarization Immunoassay ◽  
Control Material ◽  
Analytical Recovery

Abstract Samples from 33 patients being treated with digoxin and three concentrations of control material were analyzed for this drug by use of seven radioimmunoassay (RIA) kits and an automated fluorescence polarization immunoassay (FPIA) system. CVs ranged from 2.4 to 6.4% for the FPIA system and from 4.6 to 7.4% for two RIA methods. In the analysis of between-method variability of RIA kits, CVs ranged from 6.1 to 33.2%. We compared each RIA kit with the other six RIA kits (I), as well as each RIA kit with the FPIA system (II). Correlation coefficients were greater than or equal to 0.96 in all cases. Slopes ranged from 0.82 to 1.20 for comparison I and from 0.86 to 1.01 for comparison II. For the FPIA system, analytical recovery of digoxin ranged from 94 to 104%. For the RIA methods we examined, analytical recoveries ranged from 113 to 135%. Analysis time is shorter and precision is greater for the FPIA system than for the RIA methods.

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