Combined enzymic-Jaffé method for determination of creatinine in serum.

1981 ◽  
Vol 27 (1) ◽  
pp. 18-21 ◽  
Author(s):  
P Masson ◽  
P Ohlsson ◽  
I Björkhem
Keyword(s):  
Reference Method ◽  
Enzyme Reaction ◽  
Creatine Phosphate ◽  
Mass Fragmentography ◽  
Good Precision ◽  
Serum Samples ◽  
Modified Method ◽  
Combined Use ◽  
High Concentrations

Abstract Concentrations of creatinine, as determined in serum by a method involving the combined use of creatinine amidohydrolase (EC 3.5.2.10) and alkaline sodium picrate were found to be factitiously low, owing to a reversal of the enzyme reaction. This effect could be eliminated by converting creatine, the product of the enzymic reaction, to creatine phosphate. The combined enzymic-Jaffé method was therefore modified to include creatine amidohydrolase, creatine kinase, ATP, and Mg2+ in the reaction mixture. The modified method has good precision. We saw no significant interferences by relatively high concentrations of acetone, acetylacetone, ADP, creatine, creatine phosphate, glucose, glycocyamine, or pyruvate. Likewise, no interferences were evident with icteric, lipemic, or hemolytic serum samples. There was an excellent agreement between creatinine values obtained with our method and by a reference method based on isotope dilution-mass fragmentography. Our method is considerably simpler than the fully enzymic method for determination of creatinine and might be a method of choice if a high accuracy is desired.

Influence of Glucuronosyl Bilirubin and (EZ)-Cyclobilirubin on Determination of Serum Unbound Bilirubin by UB-Analyser

2002 ◽  
Vol 39 (6) ◽  
pp. 583-588 ◽  
Author(s):  
Susumu Itoh ◽  
Kou Kawada ◽  
Takashi Kusaka ◽  
Saneyuki Yasuda ◽  
Hitoshi Okada ◽  
...  
Keyword(s):  
High Performance ◽  
Total Bilirubin ◽  
Enzyme Reaction ◽  
Serum Samples ◽  
Bilirubin Concentration ◽  
Group Iii ◽  
Group I ◽  
Unbound Bilirubin ◽  
High Concentrations

Background In the enzyme reaction for the determination of the unbound (free) bilirubin concentration by glucose oxidase and peroxidase, materials with low affinity for serum protein are reactive. The influence of these materials on the determination of serum unbound bilirubin was investigated. Methods Serum samples from patients with neonatal hyperbilirubinaemia were analysed by high-performance liquid chromatography for total glucuronosyl bilirubin concentration (TGC) and (E2)-cyclobilirubin concentration [(EZ)-C]. Based on these measurements, the samples were classified into three groups: group I [13 samples, TGC < 2 μmol/L and (EZ)-C < 2·5 μmol/L]; group II [four samples, TGC < 2 μmol/L and (EZ)-C ≥ 2·5 μmol/L]; and group III (five samples, TGC ≥ 2 μmol/L). The concentrations of total bilirubin and unbound bilirubin were measured in these same samples with a UB-analyser. When the absorbance at 460 nm was monitored, the decrease in absorbance was non-linear (concave curve). The degree of concavity was estimated (D15 value) as the deviation from linearity at 15 s. Results The D15 value was significantly higher in groups II and III than in group I. D15 value correlated significantly with TGC, (EZ)-C and unbound bilirubin concentration, and the unbound bilirubin concentration correlated significantly with TGC and (EZ)-C. Conclusion These results indicated that determination of serum unbound bilirubin concentration using the UB-analyser could be positively skewed by high concentrations of TGC and (EZ)-C.

scholarly journals Determination of Essential and Toxic Elements in Cattle Blood: Serum vs Plasma

Animals ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 465 ◽  
Author(s):  
Diego Luna ◽  
Marta López-Alonso ◽  
Yolanda Cedeño ◽  
Lucas Rigueira ◽  
Víctor Pereira ◽  
...  
Keyword(s):  
Inductively Coupled Plasma ◽  
Toxic Elements ◽  
Serum Samples ◽  
Element Analysis ◽  
Inductively Coupled ◽  
Icp Ms ◽  
Plasma Mass Spectrometry ◽  
Essential And Toxic Elements ◽  
High Concentrations

This study was designed to evaluate the influence of type of blood sample (serum or plasma) on essential and toxic element analysis in cattle. Paired plasma and serum samples (n = 20) were acid digested, and the concentrations of As, B, Ba, Ca, Cd, Co, Cr, Cu, Fe, Hg, Li, Mg, Mn. Mo, Ni, P, Pb, Sb, Se, Sr and Zn were determined by inductively coupled plasma mass spectrometry (ICP-MS). The study findings indicate that plasma and serum samples appear suitable and interchangeable for the determination of most of the essential and toxic elements in blood in cattle. The only exceptions are Cu and Se, the concentrations of which were significantly lower (40.9 and 29.9% respectively) in serum than in plasma. Some of the Cu in blood samples from bovine ruminants is known to be sequestered during clotting. However, further research on Se in ruminants and other animal species is warranted. Finally, the significantly higher Mn (9.9%) concentrations in serum than in plasma may have been caused by haemolysis of some samples. Special attention should be paid to preventing haemolysis of samples during collection and processing, in order to prevent overestimation of elements present at high concentrations inside erythrocytes (i.e., Fe, Mn and Zn).

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.

A stopped-flow clinical analyzer in which immobilized-enzyme reaction loops are used.

1977 ◽  
Vol 23 (6) ◽  
pp. 1033-1036 ◽  
Author(s):  
M D Joseph ◽  
D J Kasprzak ◽  
S R Crouch
Keyword(s):  
Immobilized Enzyme ◽  
Enzymatic Reaction ◽  
Enzyme Reaction ◽  
Fixed Time ◽  
Stopped Flow ◽  
Good Precision ◽  
Indicator Reaction ◽  
Flow Mixing ◽  
Kinetic Mode

Abstract A stopped-flow clinical analyzer is described that makes use of a reaction loop containing immobilized enzyme(s) for the determination of the analyte/substrate. The analyzer has been evaluated by determining glucose with immobilized glucose oxidase. The stopped-flow mixing system was constructed at a current cost of less than $500. The analyzer separates the enzymatic reaction from a followup, spectrophotometric indicator reaction. This separation allows the enzymatic reaction to be used in either a fixed-time, kinetic mode or in an equilibrium mode. Likewise, the indicator reaction can be used in either mode. Results for glucose in blood serum indicate that good precision and accuracy can be obtained.

A new reagent strip (Visidex) for determination of glucose in whole blood.

1983 ◽  
Vol 29 (3) ◽  
pp. 438-446 ◽  
Author(s):  
M J Sherwood ◽  
M E Warchal ◽  
S T Chen
Keyword(s):  
Whole Blood ◽  
Solid Phase ◽  
Sample Volume ◽  
Operator Technique ◽  
Good Precision ◽  
Visual Resolution ◽  
Color Development ◽  
Color Scale ◽  
High Concentrations

Abstract A new solid-phase reagent strip for determination of glucose in whole blood, Visidex, has been developed specifically for visual use in conjunction with a calibrated color scale. Two reagent pads are used, each formulated for a different portion of the range of clinical values, to maximize the visual resolution available to the user. Colorimetric examination of reacted reagent pads indicated that the label color blocks match closely the appearance of the reagent pads; that the reagent pads exhibit good precision; and that the colors of the reagent pads are independent of operator technique, sample volume (20-50 microL), and effects of potential interferents studied (although high concentrations of fluoride slightly inhibited color development). Glucose measurements obtained visually with the Visidex system correlated well with values obtained with a YSI Glucose Analyzer (for two separate studies, slope = 0.96 and 1.04, r = 0.99 and 0.96, and n = 172 and 543, respectively).

Direct ultraviolet method for enzymatic determination of uric acid, with equilibrium and kinetic data-processing options.

1986 ◽  
Vol 32 (3) ◽  
pp. 486-491 ◽  
Author(s):  
B A Dilena ◽  
M J Peake ◽  
H L Pardue ◽  
J W Skoug
Keyword(s):  
Uric Acid ◽  
Data Processing ◽  
Kinetic Data ◽  
Reference Method ◽  
Plasma Equilibrium ◽  
Enzymatic Determination ◽  
Nonlinear Curve Fitting ◽  
High Concentrations ◽  
Nonlinear Curve

Abstract We developed and evaluated a direct ultraviolet method for the enzymatic determination of uric acid in serum, plasma, or urine, without deproteinization of sera and plasma. Equilibrium and nonlinear curve-fitting kinetic options are evaluated and compared, and results of the proposed method are compared with those of a candidate Reference Method. All data-processing options yield a linear relation for absorbance and concentration of uric acid between 0.1 and 2 mmol/L; with the equilibrium option, results are linear to 5 mmol/L. For 100 plasma samples, results correlate well between the proposed method (y) and a reference method (x): y = 0.99x - 0.002 mmol/L. Between-run imprecision is about 2.3%, and interference by hemolyzed, icteric, or lipemic specimens or specimens containing high concentrations of xanthine or paraproteins is minimal. The kinetic option with a data-processing range of 100 s or longer yields results that correlate well with the equilibrium method: y = 1.006x + 0.002 mmol/L (n = 118). For 20 urine samples processed by the proposed (y) and a reference (x) methods, y = 1.04x + 0.038 mmol/L.

Do we measure bilirubin correctly anno 2005?

2005 ◽  
Vol 43 (5) ◽  
Author(s):  
Joke J. Apperloo ◽  
Fedde van der Graaf ◽  
Volkher Scharnhorst ◽  
Huib L. Vader
Keyword(s):  
Reference Material ◽  
Human Serum ◽  
Reference Materials ◽  
Standard Reference Material ◽  
Total Bilirubin ◽  
Reference Method ◽  
Serum Samples ◽  
Suitable Material ◽  
Good Agreement

AbstractWe observed 30% discrepancy between liquid chemistry and dry chemistry analysers for the determination of total bilirubin in human adult serum samples, which were consistent with a 20% overestimation and 10% underestimation relative to a Jendrassik-Grof reference method, respectively. In contrast, standard reference material SRM916, which was recently recommended as being the most suitable material for attaining interlaboratory agreement, shows very good agreement on both types of analysers, as well as close to 100% recovery with respect to the reference method. We show that the liquid vs. dry bilirubin discrepancies seem to originate in the presence of either conjugated or δ-bilirubin. Our observations make it clear that good interlaboratory (or inter-analyser) agreement between bilirubin reference materials does not guarantee the same for bilirubin concentrations in human serum samples.

scholarly journals Application of Multivariate Statistical Analysis to Simultaneous Spectrophotometric Enzymatic Determination of Glucose and Cholesterol in Serum Samples

2019 ◽  
Vol 2019 ◽  
pp. 1-5 ◽  
Author(s):  
Jessica Torres-Gamez ◽  
Jose A. Rodriguez ◽  
M. Elena Paez-Hernandez ◽  
Carlos A. Galan-Vidal
Keyword(s):  
Partial Least Squares Regression ◽  
Reference Method ◽  
Least Squares Regression ◽  
Serum Samples ◽  
Multivariate Statistical ◽  
Enzymatic Determination ◽  
Proposed Model ◽  
Vis Spectroscopy ◽  
Artificial Neural

A method using UV-Vis spectroscopy and multivariate tools for simultaneous determination of glucose and cholesterol was developed in this paper. The method is based on the development of the reaction between the analytes (cholesterol and glucose) and enzymatic reagents. The spectra were analyzed by partial least squares regression and artificial neural networks. The precision estimated between nominal and calculate concentration demonstrate that artificial neural network model was adequate to quantify both analytes in serum samples, since the % relative error obtained was in the interval from 5.1 to 8.3. The proposed model was applied to analyze blood serum samples, and the results are similar compared to those obtained employing the reference method.

Immunonephelometric determination of retinol-binding protein in serum and urine.

1983 ◽  
Vol 29 (5) ◽  
pp. 853-856 ◽  
Author(s):  
M T Parviainen ◽  
P Ylitalo
Keyword(s):  
Binding Protein ◽  
Retinol Binding Protein ◽  
Good Precision ◽  
Serum Samples ◽  
Detection Range ◽  
Analytical Recovery ◽  
Beta 2 Microglobulin ◽  
Urine Specimens ◽  
Serum And Urine

Abstract An immunonephelometric method developed for measurement of retinol-binding protein (RBP) in serum and urine can detect it in concentrations of about 30 micrograms/L, which is in the lower limit of its normal concentration in urine (range 0-0.56 mg/L; mean +/- SD 0.19 +/- 0.15; n = 44). Urinary RBP was increased (range 0.93-29.5 mg/L) in all of 25 urine specimens from 13 subjects being treated with aminoglycoside (tobramycin). Urinary excretion of RBP was correlated (r = 0.83) with the excretion of beta 2-microglobulin. The within-assay and day-to-day precision (CV) was determined over the detection range of 0.03-8 mg/L. Within these limits the corresponding CVs varied from 4 to 27% and from 8 to 30%, respectively. The method had fairly good precision within the optimal measuring range of approximately 0.4 to 4.5 mg/L for both urine and 20-fold diluted serum samples. For various RBP concentrations our analytical recovery was 89-114% of added RBP. Results by this method correlated well (r = 0.96, n = 24) with those by a radial immunodiffusion method.

Optical Stress Analysis of Flexural Waves in a Bar

1970 ◽  
Vol 37 (2) ◽  
pp. 331-338 ◽  
Author(s):  
J. A. Clark ◽  
A. J. Durelli
Keyword(s):  
High Speed ◽  
Sine Wave ◽  
Good Precision ◽  
Stress Distributions ◽  
Flexural Waves ◽  
Principal Stresses ◽  
Full Field ◽  
Modified Method ◽  
Photoelastic Data

A complete, direct, full-field optical determination of dynamic stress distributions by a combination of photoelastic and interferometric measurements is illustrated. The method is applied to the study of flexural waves propagating in a photoelastic, urethane rubber bar. A displacement type of transverse, dynamic loading (which has approximately the form of a decaying sine wave) is applied at one end of the bar. The loading pulse can be repeated with good precision. Individual isochromatics and isoclinics are obtained, using a still camera with a short duration (0.5 micro sec) flash. A series of isochromatics have also been obtained with a Fastax high-speed motion picture camera. Photoelastic data are supplemented by isopachic patterns obtained by a modified method of holographic interferometry recently developed by the authors. As an example of complete determination of stress distributions, a vectorial representation of the principal stresses at one instant is given. Comparisons are made with approximate theories.

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