Total serum cholesterol by isotope dilution/mass spectrometry: a candidate definitive method.

1980 ◽  
Vol 26 (7) ◽  
pp. 854-860 ◽  
Author(s):  
A Cohen ◽  
H S Hertz ◽  
J Mandel ◽  
R C Paule ◽  
R Schaffer ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Total Cholesterol ◽  
Serum Cholesterol ◽  
Isotope Dilution ◽  
Isotope Dilution Mass Spectrometry ◽  
Weight Ratio ◽  
Molecular Ions ◽  
Total Serum ◽  
Total Serum Cholesterol ◽  
Definitive Method

Abstract We describe a highly accurate and precise method for determination of total cholesterol in serum by isotope dilution/mass spectrometry. The method was developed for a Study Group of the Committee on Standards of the American Association for Clinical Chemistry, for use in establishing the accuracy of a candidate reference method for total cholesterol, and fulfills their criteria for a definitive method. Cholesterol-d7 is added to serum, with the weight ratio of cholesterol-d7 to total serum cholesterol kept near to 1:1. The esters are hydrolyzed and the cholesterol is separated and converted into the trimethylsilyl ether derivative for measurement by combined gas chromatography/mass spectrometry. The intensity ratio of the molecular ions at m/z 465 and 458 is measured for each sample and for two calibration mixtures, according to a prescribed bracketing protocol. A weight ratio for the sample is obtained by linear interpolation of the ion-intensity ratios, and the total cholesterol is then calculated. The method was applied four times over several weeks to each of five serum pools. Statistical analysis involving consideration of both replication error and variability between weeks gave a coefficient of variation for a single measurement of 0.36%. The absence of interferences in the method was demonstrated by measurements at several other masses.

Total serum cholesterol by isotope dilution/mass spectrometry: a candidate definitive method.

1980 ◽  
Vol 26 (7) ◽  
pp. 854-860 ◽  
Author(s):  
A Cohen ◽  
H S Hertz ◽  
J Mandel ◽  
R C Paule ◽  
R Schaffer ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Total Cholesterol ◽  
Serum Cholesterol ◽  
Isotope Dilution ◽  
Isotope Dilution Mass Spectrometry ◽  
Weight Ratio ◽  
Molecular Ions ◽  
Total Serum ◽  
Total Serum Cholesterol ◽  
Definitive Method

Abstract We describe a highly accurate and precise method for determination of total cholesterol in serum by isotope dilution/mass spectrometry. The method was developed for a Study Group of the Committee on Standards of the American Association for Clinical Chemistry, for use in establishing the accuracy of a candidate reference method for total cholesterol, and fulfills their criteria for a definitive method. Cholesterol-d7 is added to serum, with the weight ratio of cholesterol-d7 to total serum cholesterol kept near to 1:1. The esters are hydrolyzed and the cholesterol is separated and converted into the trimethylsilyl ether derivative for measurement by combined gas chromatography/mass spectrometry. The intensity ratio of the molecular ions at m/z 465 and 458 is measured for each sample and for two calibration mixtures, according to a prescribed bracketing protocol. A weight ratio for the sample is obtained by linear interpolation of the ion-intensity ratios, and the total cholesterol is then calculated. The method was applied four times over several weeks to each of five serum pools. Statistical analysis involving consideration of both replication error and variability between weeks gave a coefficient of variation for a single measurement of 0.36%. The absence of interferences in the method was demonstrated by measurements at several other masses.

Total cholesterol in serum determined by isotope dilution/mass spectrometry, with liquid-chromatographic separation.

1987 ◽  
Vol 33 (7) ◽  
pp. 1113-1117 ◽  
Author(s):  
A Takatsu ◽  
S Nishi
Keyword(s):  
Mass Spectrometry ◽  
Total Cholesterol ◽  
Isotope Dilution ◽  
Chromatographic Separation ◽  
Isotope Dilution Mass Spectrometry ◽  
Gas Chromatography Mass Spectrometry ◽  
Total Serum ◽  
Total Serum Cholesterol ◽  
Liquid Chromatographic Separation ◽  
Liquid Chromatographic

Abstract We describe an accurate, precise method for determination of total serum cholesterol by isotope dilution/mass spectrometry (IDMS) with liquid-chromatographic separation. After adding [3,4-13C]cholesterol to serum and hydrolyzing the cholesterol esters, we extract the total cholesterol. "High-performance" liquid chromatography (HPLC) is used to separate the extracted cholesterol for measurement by electron-impact mass spectrometry with use of a direct-insertion device. To evaluate the specificity and the accuracy of this method, we also studied the conventional IDMS method, which involves converting cholesterol to the trimethylsilyl ether and assay by gas chromatography-mass spectrometry with use of a capillary column. The coefficient of variation for the HPLC method was a little larger than that for the conventional method, but mean values by each method agreed within 1% for all sera tested.

scholarly journals Proposed Serum Cholesterol Reference Measurement Procedure by Gas Chromatography–Isotope Dilution Mass Spectrometry

2011 ◽  
Vol 57 (4) ◽  
pp. 614-622 ◽  
Author(s):  
Selvin H Edwards ◽  
Mary M Kimberly ◽  
Susan D Pyatt ◽  
Shelton L Stribling ◽  
Kara D Dobbin ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Serum Cholesterol ◽  
Isotope Dilution ◽  
Isotope Dilution Mass Spectrometry ◽  
Measurement Procedure ◽  
Standard Reference Materials ◽  
Reference Measurement ◽  
Reference Measurement Procedure ◽  
The Mean

BACKGROUND Our purpose was to establish a mass spectrometry reference measurement procedure (RMP) for cholesterol to use in the CDC's standardization programs. We explored a gas chromatography–isotope dilution mass spectrometry (GC-IDMS) procedure using a multilevel standard calibration curve to quantify samples with varying cholesterol concentrations. METHODS We calibrated the mass spectrometry instrument by isotope dilution with a pure primary standard reference material and an isotopically enriched cholesterol analog as the internal standard (IS). We diluted the serum samples with Tris-HCl buffer (pH 7.4, 0.05 mol/L, 0.25% Triton X-100) before analysis. We used 17 serum pools, 10 native samples, and 2 standard reference materials (SRMs). We compared the GC-IDMS measurements with the CDC's modified Abell–Levy–Brodie–Kendall (AK) RMP measurements and assessed method accuracy by analyzing 2 SRMs. We evaluated the procedure for lack of interference by analyzing serum spiked with a mixture of 7 sterols. RESULTS The mean percent bias between the AK and the GC-IDMS RMP was 1.6% for all samples examined. The mean percent bias from NIST's RMP was 0.5% for the SRMs. The total %CVs for SRM 1951b levels I and II were 0.61 and 0.73%, respectively. We found that none of the sterols investigated interfered with the cholesterol measurement. CONCLUSIONS The low imprecision, linear response, lack of interferences, and acceptable bias vs the NIST primary RMP qualifies this procedure as an RMP for determining serum cholesterol. The CDC will adopt and implement this GC-IDMS procedure for cholesterol standardization.

Determination of serum urea by isotope dilution mass spectrometry as a candidate definitive method

1984 ◽  
Vol 56 (4) ◽  
pp. 713-719 ◽  
Author(s):  
Michael J. Welch ◽  
Alex. Cohen ◽  
Harry S. Hertz ◽  
Fillmer C. Ruegg ◽  
Robert. Schaffer ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Isotope Dilution ◽  
Isotope Dilution Mass Spectrometry ◽  
Serum Urea ◽  
Definitive Method

scholarly journals The effect of coffee consumption on serum total cholesterol in the Sami and Norwegian populations

2010 ◽  
Vol 13 (11) ◽  
pp. 1818-1825 ◽  
Author(s):  
Tove Nystad ◽  
Marita Melhus ◽  
Magritt Brustad ◽  
Eiliv Lund
Keyword(s):  
Total Cholesterol ◽  
Serum Cholesterol ◽  
Coffee Consumption ◽  
Cross Sectional Study ◽  
Total Serum ◽  
Total Serum Cholesterol ◽  
Cross Sectional ◽  
Cholesterol Levels ◽  
The Mean ◽  
The Impact

AbstractObjectiveTo assess coffee consumption in the Sami and Norwegian populations and to investigate the impact of unfiltered boiled coffee consumption on serum cholesterol concentrations.DesignA cross-sectional study. Information was collected by self-administrated questionnaires and total serum cholesterol was analysed. Participants were divided into three ethnic groups: Sami I (Sami used as home language in the last three generations), Sami II (at least one Sami identity marker) and Norwegian.SettingIn an area with Sami, Kven/Finnish and Norwegian populations, the SAMINOR study, 2003–2004.SubjectsA total of 5647 men and 6347 women aged 36–79 years.ResultsMore than 90 % of the study populations were coffee drinkers. Only 22 % were unfiltered coffee consumers. Sami I had the highest proportion of participants who consumed nine or more cups of unfiltered coffee per day, although the number of participants was limited. Total coffee consumption was associated with increased total cholesterol for men (P < 0·01) and women (P < 0·0001). For those who drank only unfiltered coffee, a significant association was found only in Norwegian men, adjusted for physical activity in leisure time, BMI and smoking habits (P < 0·001). From the lowest (less than five cups) to the highest (nine or more cups) unfiltered coffee consumption category, the mean total cholesterol levels increased by 0·29 mmol/l in Norwegian men.ConclusionsUnfiltered coffee consumption was lower in the present study compared to previous reports. In general, total coffee consumption was positively associated with total cholesterol levels. However, for unfiltered coffee consumption, an association was found only in Norwegian men.

Determination of Serum Glucose by Isotope Dilution Mass Spectrometry: Candidate Definitive Method

1992 ◽  
Vol 38 (3) ◽  
pp. 381-385 ◽  
Author(s):  
F Magni ◽  
R Paroni ◽  
P A Bonini ◽  
M G Kienle
Keyword(s):  
Mass Spectrometry ◽  
Isotope Dilution ◽  
Glucose Concentration ◽  
Isotope Dilution Mass Spectrometry ◽  
Internal Standard ◽  
Serum Glucose ◽  
Single Step ◽  
Simple Method ◽  
Definitive Method ◽  
Sample Purification

Abstract We report a rather simple method to determine glucose concentration in serum, using isotope dilution mass spectrometry and [13C6]glucose as internal standard. The procedure involves a single step of sample purification and the conversion of the analyte into its aldononitrile pentaacetate. The between-day and within-day contribution to total variance for a single measurement was determined by assaying Standard Reference Material (SRM) 909 serum. The method was then applied to measurement of glucose concentration in three lyophilized sera: SRM 909 and two other commercially available sera. In the two studies, the concentration of SRM 909 serum was found to be 0.8% above and 0.3% below the reported value (6.25 mmol/L), respectively; the overall coefficient of variation for determinations in all sera ranged from 0.37% to 0.56%. The precision and the accuracy of the method satisfy the requirements for a Definitive Method.

Comparison of two isotope dilution/mass spectrometric methods for determination of total serum cholesterol.

1982 ◽  
Vol 28 (1) ◽  
pp. 5-8 ◽  
Author(s):  
R Schaffer ◽  
L T Sniegoski ◽  
M J Welch ◽  
V E White ◽  
A Cohen ◽  
...  
Keyword(s):  
Serum Cholesterol ◽  
Isotope Dilution ◽  
Systematic Difference ◽  
Mass Spectrometric ◽  
Total Serum ◽  
Total Serum Cholesterol ◽  
National Bureau ◽  
Average Difference ◽  
Mean Values

Abstract Isotope dilution/mass spectrometric methods for total serum cholesterol, developed separately at the Karolinska Institutet (KI) and the National Bureau of Standards (NBS), were compared by applying them to a common set of serum pools. A search for the cause of a systematic difference of a few percent in results from the two methods revealed that the KI cholesterol standard contained lathosterol, which interfered with the calibration of the method. With NBS Standard Reference Material cholesterol used for new analyses at the KI, the average difference in mean values dropped to 0.2%. The NBS results are more precise. This is attributed to the protocols NBS used for sample preparation and mass spectrometry. However, these protocols make the NBS method more complex and time-consuming. A recent critical article on the use of this technique for total cholesterol is also examined.

Determination of steroid hormones in a human-serum reference material by isotope dilution--mass spectrometry: a candidate definitive method for cortisol.

1984 ◽  
Vol 30 (5) ◽  
pp. 619-626 ◽  
Author(s):  
D G Patterson ◽  
M B Patterson ◽  
P H Culbreth ◽  
D M Fast ◽  
J S Holler ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Human Serum ◽  
Isotope Dilution ◽  
Degradation Products ◽  
Trimethylsilyl Ether ◽  
Isotope Dilution Mass Spectrometry ◽  
Linear Interpolation ◽  
Negative Ion ◽  
Gas Chromatography Mass Spectrometry ◽  
Definitive Method

Abstract We report a method, based on isotope dilution--mass spectrometry, for determining cortisol in a pooled specimen of human serum. Isotopically labeled cortisol is added to 5.0 mL of serum so that the molar concentrations of labeled cortisol and unlabeled cortisol are approximately equal. The specimen and two calibration standards are extracted with dichloromethane, and the extracted cortisol is converted to the methoxime-trimethylsilyl ether derivative. Samples and standards are analyzed by gas chromatography--mass spectrometry by monitoring the peak areas for m/z 605 and 608. The cortisol concentration is calculated by linear interpolation between the two bracketing standards. Variances of data collected during six weeks showed that the overall coefficient of variation (CV) was 0.69% (n = 32); the within-vial CV, 0.63%; the among-vial CV, 0.22%; and the among-day CV, 0.15% (means = 3.973 nmol/vial). Method specificity was demonstrated by liquid chromatographic as well as C8 mini-column cleanup of samples before derivation, by alternative ion monitoring at m/z 636 and 639, and by negative-ion chemical ionization at m/z 459 and 462. Derivatives of all observed degradation products of cortisol under basic, neutral, and acidic conditions did not interfere.

Abstract P376: 40-year Population Trends in Cardiovascular Risk Factors in Finland

Circulation ◽  
2014 ◽  
Vol 129 (suppl_1) ◽  
Author(s):  
Katja Borodulin ◽  
Erkki Vartiainen ◽  
Markku Peltonen ◽  
Pekka Jousilahti ◽  
Anne Juolevi ◽  
...  
Keyword(s):  
Risk Factors ◽  
Blood Pressure ◽  
Body Mass Index ◽  
Total Cholesterol ◽  
Diastolic Blood Pressure ◽  
Body Mass ◽  
Serum Cholesterol ◽  
Total Serum ◽  
Total Serum Cholesterol ◽  
Chd Risk Factors

Background: Finland has experienced remarkable changes both in population levels of coronary heart disease risk factors and mortality over the past decades. For the national monitoring of risk factors in major non-communicable diseases, National FINRISK Studies have been implemented from 1972 to 2012. The 40-year changes in CHD risk factors are presented. Methods: Study population included participants aged 30 to 59 years in the series on independent random population samples. Data were collected in five-year intervals in 1972-2012. FINRISK studies so far comprised 53 589 men and women who participated in a health examination, gave a venous blood sample, and filled in questionnaires. Serum total cholesterol, systolic and diastolic blood pressure, and body mass index were measured using standardized protocol, and smoking status was recorded. Results: Total serum cholesterol decreased remarkably until the year 2007, but has thereafter turned to an increase. Systolic blood pressure has continued to decline over time since 1972, while decrease in diastolic blood pressure has leveled off during last ten years. Smoking prevalence has markedly decreased. Body mass index has increased in the population, yet the significant changes occurred in the earlier survey years, not in past 10 years. These changes in trends are shown in both sexes and all age groups in all geographical locations. Conclusions: After three decades of favorable development, the population risk factor levels showed some increase in total cholesterol and diastolic blood pressure. Some of these changes, such as in total serum cholesterol can be partially explained by unfavorable changes in dietary cholesterol intake. Our findings emphasize the need for continued efforts towards national disease prevention and health promotion.

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