A candidate reference method for determination of total protein in serum. I. Development and validation.

1981 ◽  
Vol 27 (10) ◽  
pp. 1642-1650 ◽  
Author(s):  
B T Doumas ◽  
D D Bayse ◽  
R J Carter ◽  
T Peters ◽  
R Schaffer
Keyword(s):  
Reference Material ◽  
Serum Protein ◽  
Reference Method ◽  
Total Serum Protein ◽  
Total Serum ◽  
National Bureau ◽  
Bovine Albumin ◽  
Color Development ◽  
Development And Validation

Abstract We developed a candidate Reference Method for measuring total serum protein by use of the biuret reaction. The method involves a previously described biuret reagent (Clin. Chem. 21: 1159, 1975) and Standard Reference Material (SRM) 927 bovine albumin (National Bureau of Standards) as the standard. At 25 degrees C, color development for 30 or 60 min provides identical serum protein values. Glucose (up to 10 g/L) and bilirubin (up to 300 mg/L) do not interfere. Hemoglobin, at 3 g/L, increases apparent serum protein by 0.4 g/L. The presence of dextran in serum causes easily detected turbidity, but this interference can be eliminated by centrifuging the reaction mixture. Therapeutic concentrations of ampicillin, carbenicillin, penicillin, oxacillin, nafcillin, chloramphenicol, cephalothin, and methicillin in blood do not interfere, nor do triglycerides up to 10 g/L. Within-run and day-to-day standard deviations of the method are 0.1 and 0.4 g/L, respectively.

A candidate reference method for determination of total protein in serum. II. Test for transferability.

1981 ◽  
Vol 27 (10) ◽  
pp. 1651-1654 ◽  
Author(s):  
B T Doumas ◽  
D D Bayse ◽  
K Borner ◽  
R J Carter ◽  
F Elevitch ◽  
...  
Keyword(s):  
United States ◽  
Bovine Serum Albumin ◽  
Reference Method ◽  
The United States ◽  
Total Serum Protein ◽  
Total Serum ◽  
National Bureau ◽  
Calibration Standard ◽  
The Mean

Abstract The transferability of the candidate Reference Method for total serum protein was tested in eight laboratories in the United States and Europe. National Bureau of Standards SRM 927 (bovine serum albumin) was used in each analytical run as the calibration standard. The mean absorptivity value obtained for this material was 0.2983 L g-1 cm-1. Four serum pools prepared at the Centers for Disease Control were analyzed on each of 15 days. Within-run variation of the protein values (expressed as CV) in the eight laboratories ranged from 0.1 to 2.5% and day-to-day (total) variation in six of the laboratories ranged from 0.4 to 1%.

Effect of protein concentration on the determination of digoxin in serum by fluorescence polarization immunoassay.

1984 ◽  
Vol 30 (11) ◽  
pp. 1826-1829 ◽  
Author(s):  
W H Porter ◽  
V M Haver ◽  
B A Bush
Keyword(s):  
Serum Protein ◽  
Total Protein ◽  
Fluorescence Polarization ◽  
Protein Concentration ◽  
Total Serum Protein ◽  
Total Serum ◽  
Fluorescence Polarization Immunoassay ◽  
Total Protein Concentration ◽  
Protein Pellet

Abstract Determination of digoxin by fluorescence polarization immunoassay (FPIA) with the Abbott "TDx" is significantly influenced by the concentration of total serum protein. Each 10 g/L increase in serum protein results in an 8% decrease in measured digoxin. Studies with [3H]digoxin confirmed that digoxin binds to the protein pellet during the trichloroacetic acid precipitation step before the immunoassay. Serum protein, or equal concentrations of albumin or gamma-globulin, exert an equivalent effect on the apparent digoxin value. Because the total protein concentration of the assay calibrators is low (50 g/L) compared with its reference interval in serum (60-80 g/L), results by FPIA may be expected to be low by an average of 16% (range, 8-24%). Digoxin results by FPIA will be most nearly accurate when the calibrators include a total protein concentration of about 70 g/L. Patients' specimens with abnormally high or low protein content will give falsely high or low results for digoxin.

Quantification of nonenzymically glycated albumin and total serum protein by affinity chromatography.

1984 ◽  
Vol 30 (3) ◽  
pp. 446-449 ◽  
Author(s):  
R W Yatscoff ◽  
G J Tevaarwerk ◽  
J C MacDonald
Keyword(s):  
Serum Protein ◽  
Protein Concentration ◽  
Glycated Albumin ◽  
Normal Subjects ◽  
Total Serum Protein ◽  
Total Serum ◽  
Exclusion Chromatography ◽  
Free Glucose ◽  
Chromatographic Procedure

Abstract We have evaluated an affinity-chromatographic procedure for determination of glycated albumin (GA) and glycated total serum protein (GSP). Recovery of these analytes was inversely related to free glucose concentration, thus necessitating removal of free glucose. For this we used molecular-exclusion chromatography on G-25 Sephadex, or dialysis, the latter procedure resulting in significantly (p less than 0.05) lower concentrations of GSP and GA. Total protein concentration and percent glycation are also inversely related, and so protein concentrations must be standardized before the assay. Within- and between-run CVs for both GSP and GA were less than 6.5 and 18%, respectively, the determination of GA being generally the more precise of the two. Labile glycated fractions, lipemia, icterus, hemolysis, and type of anticoagulant did not affect the results, but assay temperature did. Diabetic subjects showed substantially higher concentrations of GA and GSP than did normal subjects. Because of the life span of these analytes in circulation, their measurement may provide a short-term index of glycemic control.

Candidate reference method for determination of total bilirubin in serum: development and validation.

1985 ◽  
Vol 31 (11) ◽  
pp. 1779-1789 ◽  
Author(s):  
B T Doumas ◽  
P P Kwok-Cheung ◽  
B W Perry ◽  
B Jendrzejczak ◽  
R B McComb ◽  
...  
Keyword(s):  
Ascorbic Acid ◽  
Total Bilirubin ◽  
Reference Method ◽  
Molar Absorptivity ◽  
National Bureau ◽  
Albumin Solution ◽  
Intraindividual Variation ◽  
Therapeutic Drugs ◽  
Development And Validation

Abstract This candidate Reference Method for measuring total bilirubin in serum is based on the Jendrassik-Gróf principle (Clin Chem 29: 297-301, 1983). Standard Reference Material no. 916 bilirubin (National Bureau of Standards) is used as the standard. Bilirubin standard solutions may be prepared either in human serum or in 40 g/L albumin solution (human or bovine), because we found the molar absorptivity of the azopigment at 598 nm to be identical in these media. The absorptivities of the unconjugated and conjugated azopigments appear to be identical, but the conjugated azopigment is completely hydrolyzed in the final reaction mixture. Bilirubin added to serum from adults or neonates was quantitatively accounted for. Interference by hemoglobin (up to 2 g/L), ascorbic acid (up to 20 mg/L), or zinc (at physiological concentrations) is negligible. Of the therapeutic drugs we tested, only L-dopa and alpha-methyldopa interfere. We established normal adult reference values for total bilirubin and examined the intraindividual variation in 19 subjects.

Kinetic Determination of Total Serum Protein with a Centrifugal Analyzer

1974 ◽  
Vol 20 (3) ◽  
pp. 392-394 ◽  
Author(s):  
Thomas R Koch ◽  
George F Johnson ◽  
Max E Chilcote
Keyword(s):  
Kinetic Analysis ◽  
Serum Protein ◽  
Analytical Method ◽  
Clinical Laboratory ◽  
Total Serum Protein ◽  
Total Serum ◽  
Kinetic Determination ◽  
First Order

Abstract A kinetic biuret assay of total serum protein on the "CentrifiChem" centrifugal analyzer is shown to be rapid, accurate, and reasonably precise, and accommodates the most desirable analytical method and standardization currently available. Kinetic analysis of compounds undergoing first-order reactions is a useful type of analysis that is of significant advantage to the clinical laboratory.

Polarographic determination of total serum protein

1977 ◽  
Vol 81 (1) ◽  
pp. 151-159 ◽  
Author(s):  
P.W. Alexander ◽  
R. Hoh ◽  
L.E. Smythe
Keyword(s):  
Serum Protein ◽  
Polarographic Determination ◽  
Total Serum Protein ◽  
Total Serum
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