scholarly journals Reagent-free, Simultaneous Determination of Serum Cholesterol in HDL and LDL by Infrared Spectroscopy

2002 ◽  
Vol 48 (3) ◽  
pp. 499-506 ◽  
Author(s):  
Kan-Zhi Liu ◽  
R Anthony Shaw ◽  
Angela Man ◽  
Thomas C Dembinski ◽  
Henry H Mantsch
Keyword(s):  
Ir Spectroscopy ◽  
Ldl Cholesterol ◽  
Clinical Laboratory ◽  
Hdl Cholesterol ◽  
Serum Samples ◽  
Clinical Method ◽  
Predicted Values ◽  
Friedewald Formula ◽  
Spectral Ranges

Abstract Background: The purpose of this study was to assess the feasibility of infrared (IR) spectroscopy for the simultaneous quantification of serum LDL-cholesterol (LDL-C) and HDL-cholesterol (HDL-C) concentrations. Methods: Serum samples (n = 90) were obtained. Duplicate aliquots (5 μL) of the serum specimens were dried onto IR-transparent barium fluoride substrates, and transmission IR spectra were measured for the dry films. In parallel, the HDL-C and LDL-C concentrations were determined separately for each specimen by standard methods (the Friedewald formula for LDL-C and an automated homogeneous HDL-C assay). The proposed IR method was then developed with a partial least-squares (PLS) regression analysis to quantitatively correlate IR spectral features with the clinical analytical results for 60 randomly chosen specimens. The resulting quantification methods were then validated with the remaining 30 specimens. The PLS model for LDL-C used two spectral ranges (1700–1800 and 2800–3000 cm−1) and eight PLS factors, whereas the PLS model for HDL-C used three spectral ranges (800–1500, 1700–1800, and 2800–3500 cm−1) with six factors. Results: For the 60 specimens used to train the IR-based method, the SE between IR-predicted values and the clinical laboratory assays was 0.22 mmol/L for LDL-C and 0.15 mmol/L for HDL-C (r = 0.98 for LDL-C; r = 0.91 for HDL-C). The corresponding SEs for the test spectra were 0.34 mmol/L (r = 0.96) and 0.26 mmol/L (r = 0.82) for LDL-C and HDL-C, respectively. The precision for the IR-based assays was estimated by the SD of duplicate measurements to be 0.11 mmol/L (LDL-C) and 0.09 mmol/L (HDL-C). Conclusions: IR spectroscopy has the potential to become the clinical method of choice for quick and simultaneous determinations of LDL-C and HDL-C.

scholarly journals New immunoseparation-based homogeneous assay for HDL-cholesterol compared with three homogeneous and two heterogeneous methods for HDL-cholesterol

1998 ◽  
Vol 44 (7) ◽  
pp. 1443-1451 ◽  
Author(s):  
Matthias Nauck ◽  
Winfried März ◽  
Heinrich Wieland
Keyword(s):  
Magnetic Beads ◽  
Ldl Cholesterol ◽  
Correlation Coefficients ◽  
Hdl Cholesterol ◽  
Serum Samples ◽  
Fresh Serum ◽  
Homogeneous Assay ◽  
Vldl Triglyceride ◽  
Homogeneous Assays

Abstract We evaluated four new commercial methods for HDL-cholesterol determination. The three completely homogeneous assays were an immunoseparation-based (IS) method from Wako, a polyethylene glycol-modified enzyme (PEG) method from Boehringer Mannheim, and a synthetic polymer-based (SP) method from Genzyme. The fourth method was a new heterogeneous method in which lipoproteins are removed using dextran sulfate-coated magnetic beads and Mg2+ (MB, Reference Diagnostics). We compared these methods with the conventional phosphotungstic acid/MgCl2 precipitation (PTA) procedure. The homogeneous assays had good intraassay imprecision with total CVs <2.3%, whereas the CVs of the MB assay were <5.9%. Adding HDL to serum to achieve HDL-cholesterol (HDL-C) concentrations up to 1000 mg/L revealed nearly complete recoveries in the IS, PEG, and MB assays, whereas the SP assay showed a lower recovery (∼70%). The SP HDL-C apparently increased at increasing LDL-cholesterol and VLDL-triglyceride concentrations, whereas the IS, PEG, and MB methods were not influenced by LDL-cholesterol up to 6 000 mg/L (MB, 5 000 mg/L) and VLDL-triglycerides up to 9 000 mg/L. Free fatty acids above ∼2 mmol/L produced falsely high HDL-C in the IS and SP assays, the error amounting to as much as 50% in some samples. An intermethod comparison in 291 fresh serum samples yielded correlation coefficients of at least r = 0.95 for all assays, when compared with the PTA procedure. The slopes and intercepts of the regression lines were 1.05 and 57 (IS), 1.12 and 9.9 (PEG), 1.00 and 39 (SP), and 1.0 and 38 mg/L (MB), respectively. The new assays are precise and simplify the determination of HDL-C, but in part they lack specificity or are susceptible to interferences, resulting in discrepancies when compared with the established PTA procedure.

Relation of lipoprotein(a) in 11- to 19-year-old adolescents to parental cardiovascular heart disease

1993 ◽  
Vol 39 (3) ◽  
pp. 477-480 ◽  
Author(s):  
J C Vella ◽  
E Jover
Keyword(s):  
Heart Disease ◽  
Ldl Cholesterol ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Hdl Cholesterol ◽  
Young Population ◽  
Serum Samples ◽  
Apo B ◽  
Lipoprotein A ◽  
Cardiovascular Heart Disease

Abstract We studied several risk factors in relation to parental cardiovascular heart disease: total cholesterol, triglycerides, high-density lipoprotein (HDL) cholesterol, low-density lipoprotein (LDL) cholesterol, apolipoprotein (apo) A-I, apo B, and lipoprotein(a) [Lp(a)] were determined in 322 serum samples (43 from subjects with and 279 without parental cardiovascular heart disease). The distribution of Lp(a) concentrations in our young population was similar to that of other white populations, i.e., markedly skewed, with higher frequencies at low values. As compared with children whose parents did not report cardiovascular heart disease, those with affected parents had a higher mean Lp(a) (0.23 vs 0.18 g/L; P < 0.05). Moreover, 42% of the children with parental cardiovascular heart disease, but only 19% of those with no parental cardiovascular heart disease, exhibited Lp(a) values > 0.30 g/L. These results suggest not only that Lp(a) is an important risk factor for cardiovascular heart disease, but also that Lp(a) is more strongly related to the risk of cardiovascular heart disease than are HDL- and LDL-cholesterol and apo A-I and B.

scholarly journals Analytical and Clinical Evaluation of Two Homogeneous Assays for LDL-Cholesterol in Hyperlipidemic Patients

2000 ◽  
Vol 46 (8) ◽  
pp. 1121-1131 ◽  
Author(s):  
Margarita Esteban-Salán ◽  
Amada Guimón-Bardesi ◽  
Jesús María de la Viuda-Unzueta ◽  
María Nerea Azcarate-Ania ◽  
Pilar Pascual-Usandizaga ◽  
...  
Keyword(s):  
Ldl Cholesterol ◽  
Treatment Guidelines ◽  
Clinical Performance ◽  
Total Error ◽  
Direct Methods ◽  
Lipid Lowering ◽  
Serum Samples ◽  
Wide Range ◽  
Friedewald Formula ◽  
Homogeneous Assays

Abstract Background: LDL-cholesterol (LDL-C) concentrations are the primary basis for treatment guidelines established for hyperlipidemic patients. LDL-C concentrations are commonly monitored by means of the Friedewald formula, which provides a relative estimation of LDL-C concentration when the triglyceride concentration is <2000 mg/L and there are no abnormal lipids. The Friedewald formula has several limitations and may not meet the current total error requirement of <12% in LDL-C measurements. Methods: We evaluated the analytical and clinical performance of two direct methods (Roche and Wako) by analyzing 313 fresh serum samples obtained from dyslipidemic patients in a lipid clinic and comparing them with modified β-quantification. Results: Both homogeneous assays displayed excellent precision (CV <2%). The Roche method showed a mean total error of 7.72%, and the Wako method showed a mean total error of 4.46% over a wide range of LDL-C concentrations. The Roche method correlated highly with the modified β-quantification assay (r = 0.929; y = 1.052x − 168 mg/L; n = 166) and showed a bias of −4.5% as a result of the assigned standard value. The Wako method also correlated highly with β-quantification (r = 0.966; y = 0.9125x + 104.8 mg/L; n = 145) without significant bias. The Roche method correctly classified 97% of patients with triglycerides <2000 mg/L, 75% of patients with type IIb hyperlipemia (HPL), and 84% of patients with type IV HPL based on the cutpoints of 1300 and 1600 mg/L, compared with 98%, 78.4%, and 89%, respectively, for the Wako method. In dysbetalipoproteinemic patients, both methods have a 30% mean positive bias compared with β-quantification. Conclusions: Both direct methods can be a useful alternative when ultracentrifugation is not available for the diagnosis and control of lipid-lowering medication for patients with mixed HPL, but not for patients with type III hyperlipidemia.

scholarly journals Measurements for 8 Common Analytes in Native Sera Identify Inadequate Standardization among 6 Routine Laboratory Assays

2014 ◽  
Vol 60 (6) ◽  
pp. 855-863 ◽  
Author(s):  
Hedwig C M Stepman ◽  
Ulla Tiikkainen ◽  
Dietmar Stöckl ◽  
Hubert W Vesper ◽  
Selvin H Edwards ◽  
...  
Keyword(s):  
Uric Acid ◽  
Ldl Cholesterol ◽  
Peer Group ◽  
Clinical Chemistry ◽  
Total Error ◽  
Random Access ◽  
Reference Method ◽  
Hdl Cholesterol ◽  
Serum Samples ◽  
Fresh Frozen

Abstract BACKGROUND External quality assessment (EQA) with commutable samples is essential for assessing the quality of assays performed by laboratories, particularly when the emphasis is on their standardization status and interchangeability of results. METHODS We used a panel of 20 fresh-frozen single-donation serum samples to assess assays for the measurement of creatinine, glucose, phosphate, uric acid, total cholesterol, HDL cholesterol, LDL cholesterol, and triglycerides. The commercial random access platforms included: Abbott Architect, Beckman Coulter AU, Ortho Vitros, Roche Cobas, Siemens Advia, and Thermo Scientific Konelab. The assessment was done at the peer group level and by comparison against the all-method trimmed mean or reference method values, where available. The considered quality indicators were intraassay imprecision, combined imprecision (including sample–matrix interference), bias, and total error. Fail/pass decisions were based on limits reflecting state-of-the-art performance, but also limits related to biological variation. RESULTS Most assays showed excellent peer performance attributes, except for HDL- and LDL cholesterol. Cases in which individual assays had biases exceeding the used limits were the Siemens Advia creatinine (−4.2%), Ortho Vitros phosphate (8.9%), Beckman Coulter AU triglycerides (5.4%), and Thermo Scientific Konelab uric acid (6.4%), which lead to considerable interassay discrepancies. Additionally, large laboratory effects were observed that caused interlaboratory differences of >30%. CONCLUSIONS The design of the EQA study was well suited for monitoring different quality attributes of assays performed in daily laboratory practice. There is a need for improvement, even for simple clinical chemistry analytes. In particular, the interchangeability of results remains jeopardized both by assay standardization issues and individual laboratory effects.

Lipoprotein subfraction LDL-5 and the presence of coronary atherosclerosis

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
M Klevjer ◽  
J.C Saether ◽  
E Vesterbekkmo ◽  
G Giskeoedegaard ◽  
T Bathen ◽  
...  
Keyword(s):  
Total Cholesterol ◽  
Coronary Atherosclerosis ◽  
Ldl Cholesterol ◽  
Density Lipoprotein ◽  
Hdl Cholesterol ◽  
Funding Source ◽  
Serum Samples ◽  
Cvd Risk ◽  
Lipoprotein Subfractions ◽  
Ldl Particles

Abstract Background Coronary artery disease (CAD) has high mortality rates and is a frequent cause of death globally. Serum lipids play a pivotal role in the development of atherosclerosis, and elevated levels of total cholesterol, low density lipoprotein (LDL) cholesterol, and triglycerides are well known risk factors of cardiovascular disease (CVD). However, there are limitations in the ability to predict CVD risk, which has led to an increased clinical interest in identifying novel risk markers. With the advances in lipidomic technology, lipoprotein subfractions may provide additional information that is missing in today's evaluation of CVD risk. Lipoprotein subfractions differ in size and density, and recent studies suggest that high density of small LDL particles provide a greater risk for CVD. Purpose To investigate whether lipoprotein subfractions are associated with the presence and extent of coronary atherosclerosis. Methods Fasting serum samples from 60 participants with suspected stable CAD were collected before scheduled coronary angiography, and analysed by nuclear magnetic resonance (NMR). The presence and extent of atherosclerosis were quantified by the Gensini Score. Participants were classified into one of three Gensini groups based on severity (<20.5, normal; 20.6–30, non-significant CAD; >30.1, significant CAD). Results A three-way ANOVA, adjusted for statin-use and sex, revealed statistically significant differences (p<0.005) in LDL-5 particle number, LDL-5 triglycerides, and LDL-5 phospholipids between the Gensini groups. In addition, significant differences (p<0.005) were found in the ratios apolipoprotein A/apolipoprotein B and LDL cholesterol/HDL cholesterol between the Gensini groups. All significant variables, identified by the three-way ANOVA, displayed the highest levels in the Gensini group with significant CAD. Conclusion Despite no difference in the traditional clinical measurements (total cholesterol, LDL cholesterol, HDL cholesterol and triglycerides), NMR-lipidomics revealed significant differences in LDL-5 between the Gensini groups. Interestingly, our results reveal that those with significant CAD have a higher density of small LDL subfractions. Funding Acknowledgement Type of funding source: Foundation. Main funding source(s): Norwegian Health Association, The Liaison Committee for Education, Research and Innovation in Central Norway

scholarly journals Effects ofSalvadora persicaExtract on the Hematological and Biochemical Alterations against Immobilization-Induced Rats

Scientifica ◽  
2015 ◽  
Vol 2015 ◽  
pp. 1-5 ◽  
Author(s):  
Kholoud S. Ramadan ◽  
Salha A. Alshamrani
Keyword(s):  
Biochemical Parameters ◽  
Hematological Parameters ◽  
Hdl Cholesterol ◽  
Treated Group ◽  
Control Group ◽  
Serum Samples ◽  
Salvadora Persica ◽  
Biochemical Alterations ◽  
Hematological And Biochemical Parameters

A total of 24 rats were divided into 4 groups: control, stress, extract alone, and stress + extract (n=6each), for total 21 days of treatment. The immobilization stress was induced in rats by putting them in 20 cm × 7 cm plastic tubes for 2 h/day for 21 days. Rats were postorally treated withSalvadora persicaat a dose of 900 mg/kg body weight via intragastric intubations. At the end of the test period, hematological and biochemical parameters were determined in blood and serum samples with determination of vital organs weights. The vital organ weights were not significantly affected in stressed rats as compared to control rats. Compared to the control group, the stress treated group showed significances in several hematological parameters, including decreases in WBC, RBC, and PLT counts. Furthermore, in comparison to the control group, the stress group showed significantly increased blood glucose, serum total cholesterol, LDL-cholesterol, and triacylglycerols levels and decreased HDL-cholesterol level. The hematological and biochemical parameters in the stress + extract treated group were approximately similar to control group. The SP extract restored the changes observed following stress treatment.

Enzymatic determination of sodium, potassium, and chloride in abnormal (hemolyzed, icteric, lipemic, paraproteinemic, or uremic) serum samples compared with indirect determination with ion-selective electrodes

1994 ◽  
Vol 40 (8) ◽  
pp. 1528-1531 ◽  
Author(s):  
W Hübl ◽  
R Wejbora ◽  
I Shafti-Keramat ◽  
A Haider ◽  
P Hajdusich ◽  
...  
Keyword(s):  
Clinical Laboratory ◽  
National Committee ◽  
Ion Selective Electrodes ◽  
Serum Samples ◽  
Sodium Potassium ◽  
Indirect Determination ◽  
Enzymatic Determination ◽  
Uremic Serum ◽  
Enzymatic Methods

Abstract We evaluated the effect of hemolysis, icteric discoloration, lipemia, paraproteinemia, and uremia on enzymatic methods for determining sodium, potassium, and chloride, according to the National Committee for Clinical Laboratory Standards EP7-P proposals for testing interference from endogenous substances. The sodium, potassium, and chloride assays (reagent kits supplied by Boehringer Mannheim) were based on electrolyte-dependent beta-galactosidase, pyruvate kinase, and alpha-amylase, respectively. The results were compared with those obtained by indirect ion-selective electrodes (ISE), which in turn had been validated by flame photometry. We analyzed the samples with Hitachi 717, 737, and 911 chemistry analyzers and with an IL943 flame photometer. The enzymatic results were in good agreement with those by ISE, the interference-related differences generally being without clinical significance; however, none of the enzymatic methods could analyze grossly lipemic samples.

Direct determination of free thyroxin in undiluted serum by equilibrium dialysis/radioimmunoassay.

1988 ◽  
Vol 34 (9) ◽  
pp. 1737-1744 ◽  
Author(s):  
J C Nelson ◽  
R T Tomei
Keyword(s):  
Clinical Laboratory ◽  
Equilibrium Dialysis ◽  
Direct Determination ◽  
Primary Hypothyroidism ◽  
Serum Samples ◽  
Free T4 ◽  
Central Hypothyroidism ◽  
Undiluted Serum ◽  
Dialysis Cell

Abstract We have designed a re-usable dialysis cell and a complex dialysis buffer, with which undiluted serum samples can be dialyzed with minimal changes in their serum matrix. Dialysate thyroxin (free T4) is then measured by a sensitive RIA for T4. The range of reportability was 2-128 ng/L, the normal range was 8-27 ng/L, and the interassay CV was 7%. Free T4 concentrations in various disorders were as follows: hyperthyroidism, 32-478 ng/L; in both excess thyroxin-binding globulin (TBG) and familial dysalbuminemic hyperthyroxinemia, 9-27 ng/L; primary hypothyroidism, less than 2-7 ng/L; central hypothyroidism, 4-6 ng/L; severe TBG deficiency, 9-25 ng/L; hypothyroxinemias of nonthyroidal illness, 8-35 ng/L. With this free-T4 assay, which is adaptable to clinical laboratory use, one can differentiate hyperthyroidism from the major euthyroid hyperthyroxinemias and hypothyroidism from the major euthyroid hypothyroxinemias.

scholarly journals Inaccuracy of Lipid Measurements with the Portable Cholestech L·D·X Analyzer in Patients with Hypercholesterolemia

2002 ◽  
Vol 48 (2) ◽  
pp. 284-290 ◽  
Author(s):  
James H Stein ◽  
Cynthia M Carlsson ◽  
Kristi Papcke-Benson ◽  
Jean A Einerson ◽  
Patrick E McBride ◽  
...  
Keyword(s):  
Ldl Cholesterol ◽  
Clinical Laboratory ◽  
Hdl Cholesterol ◽  
Fasting Serum ◽  
High Incidence ◽  
Lipid Guidelines ◽  
Wide Variability ◽  
Unbiased Estimates ◽  
The Mean ◽  
Middle Aged Adults

Abstract Background: Although total cholesterol concentrations measured by portable lipid analyzers have acceptable bias and precision in young and middle-aged adults, clinically relevant differences in HDL-cholesterol (HDL-C) and triglyceride values have been described. Furthermore, the accuracy of portable lipid analyzers in older hyperlipidemic individuals, who have a high incidence of coronary heart disease, has not been validated. This study determined the biases and variability in portable lipid measurements in older patients with hypercholesterolemia and related them to National Cholesterol Education Program Adult Treatment Panel III guidelines. Methods: Participants were ≥70 years of age with fasting serum LDL-cholesterol (LDL-C) concentrations >1.40 g/L. Fasting fingerstick samples were analyzed on a Cholestech L·D·X desktop analyzer. Antecubital venous samples were analyzed in a proficiency-certified clinical laboratory. Results: Portable measurements systematically overestimated triglycerides (0.296 g/L; P <0.001) and HDL-C (0.015 g/L; P = 0.026). LDL-C concentrations were underestimated (0.043 g/L; P = 0.046). Total and non-HDL cholesterol calculations based on the portable lipid device provided unbiased estimates, but wide variability was present. Significant variability in lipid determinations limited their clinical usefulness in individual patients, especially because 2 SD of the mean bias between the laboratory and the portable determinations of LDL-C and non-HDL cholesterol exceeded the 0.30 g/L cutoff that defines treatment targets in the current lipid guidelines. Conclusions: Lipid values obtained from portable lipid analyzers may be useful for screening, but they should not be used to make clinical decisions regarding the diagnosis and management of dyslipidemia in individual patients.

Enzyme immunoassay with flow-amperometric detection of NADH.

1982 ◽  
Vol 28 (9) ◽  
pp. 1848-1851 ◽  
Author(s):  
H M Eggers ◽  
H B Halsall ◽  
W R Heineman
Keyword(s):  
Clinical Laboratory ◽  
Amperometric Detection ◽  
Electrochemical Technique ◽  
Serum Samples ◽  
Laboratory Procedure ◽  
Detection Range ◽  
Optimum Detection ◽  
Routine Clinical Laboratory ◽  
Good Agreement

Abstract Using phenytoin as a model analyte, we demonstrate that an enzyme-coupled immunoassay based on flow-injection analysis and amperometric detection of NADH is both feasible and practical. Good agreement with a routine clinical laboratory procedure for phenytoin was obtained for patients' serum samples. The electrode must be protected to prevent fouling by proteins in the analytical sample. The optimum detection range for NADH was at 0.01 of the concentrations of NADH generated during the several minutes required for each analysis. This suggests that the electrochemical technique should be extendable to the determination of species at concentrations in the microgram per liter range.

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