Home About us Editorial board Search Ahead of print Current issue Archives Submit article Instructions Subscribe Contacts Login 
  Users Online: 709 Home Print this page Email this page Small font sizeDefault font sizeIncrease font size  

 Table of Contents  
ORIGINAL ARTICLE
Year : 2017  |  Volume : 7  |  Issue : 1  |  Page : 57-62  

Correlation of Friedewald's calculated low-density lipoprotein cholesterol levels with direct low-density lipoprotein cholesterol levels in a tertiary care hospital


1 Department of Biochemistry, Pondicherry Institute of Medical Sciences, Affiliated to Pondicherry University, Puducherry, India
2 Department of Biostatistics, Pondicherry Institute of Medical Sciences, Affiliated to Pondicherry University, Puducherry, India

Date of Submission02-Feb-2016
Date of Acceptance03-May-2016
Date of Web Publication17-Jan-2017

Correspondence Address:
Sunil Kumar Nanda
Department of Biochemistry, Pondicherry Institute of Medical Sciences, Affiliated to Pondicherry University, Kalapet, Puducherry
India
Login to access the Email id

Source of Support: None, Conflict of Interest: None


DOI: 10.4103/2229-516X.198525

Rights and Permissions
   Abstract 

Background: One of the risk factors for the development of coronary heart disease is high low-density lipoprotein (LDL) cholesterol levels. National Cholesterol Education Program ATP III guidelines suggest drug therapy to be considered at LDL-cholesterol levels >130 mg/dl. This makes accurate reporting of LDL cholesterol crucial in the management of Coronary heart disease. Estimation of LDL cholesterol by direct LDL method is accurate, but it is expensive. Hence, We compared Friedewald's calculated LDL values with direct LDL values. Aim: To evaluate the correlation of Friedewalds calculated LDL with direct LDL method. Materials and Methods: We compared LDL cholesterol measured by Friedewald's formula with direct LDL method in 248 samples between the age group of 20-70 years. Paired t-test was used to test the difference in LDL concentration obtained by a direct method and Friedewald's formula. The level of significance was taken as P < 0.05. Pearsons correlation formula was used to test the correlation between direct LDL values with Friedewald's formula. Results: There was no significant difference between the direct LDL values when compared to calculated LDL by Friedewalds formula (P = 0.140). Pearson correlation showed there exists good correlation between direct LDL versus Friedewalds formula (correlation coefficient = 0.98). The correlation between direct LDL versus Friedewalds calculated LDL was best at triglycerides values between 101 and 200 mg/dl. Conclusion: This study indicates calculated LDL by Friedewalds equation can be used instead of direct LDL in patients who cannot afford direct LDL method.

Keywords: Coronary heart disease, direct low-density lipoprotein, Friedewalds formula


How to cite this article:
Nanda SK, Bharathy M, Dinakaran A, Ray L, Ravichandran K. Correlation of Friedewald's calculated low-density lipoprotein cholesterol levels with direct low-density lipoprotein cholesterol levels in a tertiary care hospital. Int J App Basic Med Res 2017;7:57-62

How to cite this URL:
Nanda SK, Bharathy M, Dinakaran A, Ray L, Ravichandran K. Correlation of Friedewald's calculated low-density lipoprotein cholesterol levels with direct low-density lipoprotein cholesterol levels in a tertiary care hospital. Int J App Basic Med Res [serial online] 2017 [cited 2020 Oct 31];7:57-62. Available from: https://www.ijabmr.org/text.asp?2017/7/1/57/198525


   Introduction Top


One of the major risk factors for the development of coronary heart disease is high low-density lipoprotein (LDL) cholesterol. [1],[2],[3],[4] Reduction in LDL cholesterol levels decreases the risk of development of coronary heart disease. [5],[6] LDL is a lipoprotein made up of outer phospholipids, apolipoproteins, free cholesterol and inner triglycerides (TGs) and cholesterol ester. It carries cholesterol from the liver to the peripheral tissues. The apolipoprotein present in LDL is Apo B 100. [7] LDL fractionn has a hydrated density ranging from 1.006 to 1.063 kg/L. [8]

β-quantification is the standard method for estimating LDL, which includes ultracentrifugation and chemical precipitation. β-quantification requires ultracentrifuges and takes time, delaying the turnaround time and hence cannot be employed in day to day practice. Automated methods are available for direct LDL estimation which is expensive and requires significant time for analysis. [8],[9] Friedewald et al. came up with a formula for estimating LDL using total cholesterol, high-density lipoprotein (HDL) cholesterol and TGs. [10] According to Friedewalds formula, TGs divided by five gives the value of very-LDL (VLDL). TGs >400 mg/dl, disorders related to lipoproteins (Type III hyperlipoproteinemia) and secondary hyperlipoproteinemias are conditions wherein Friedewalds equation for calculating LDL cannot be employed since these conditions decrease the accuracy of Friedewalds equation in estimating LDL. [10] The accuracy and targets to be achieved regarding the analytical performance of LDL cholesterol were issued by National Cholesterol Education Program (NCEP) panel. As per NCEP guidelines, precision should be <4%, bias < 4% and total analytical error should be < 12%. [11] Falsely, low values of LDL cholesterol has been reported in conditions such as diabetes mellitus, advanced renal disease and liver failure due to elevated TGs in these conditions. [8],[12],[13],[14] In spite of these well-established limitations of Friedewalds equation in estimating LDL cholesterol, it remains to be widely employed. Many studies have been published questioning the accuracy of Friedewalds equation in measuring LDL cholesterol especially at levels of TGs above the normal range. [11],[15],[16],[17],[18]

This study was taken up to study the accuracy of Friedewalds calculated LDL in comparison to direct LDL method.


   Materials and Methods Top


The current study was a validation study. Assuming a paired mean difference of 12.39 ± 67.0 between the LDL measured by the direct and Friedewald method, the sample size required for the study was estimated to be 234 to achieve 80% power of the study and 5% significance level.

Inclusion criteria

Lipid profile was estimated in 248 samples which were estimated in venous blood drawn after 12 h of fasting between the age group of 20-70 years. The blood was collected in plain tubes centrifuged at 3000 rpm for 15 min. The serum liberated was analyzed for lipid profile.

Exclusion criteria

Patients with TGs more than 400 mg/dl, diabetes mellitus, advanced renal disease and patients with liver failure, patients receiving lipid-lowering drugs were excluded from the study. The period of the study was from February 2015 to June 2015.

The following tests were done in Cobas Integra 400 plus from Roche Diagnostics. The principle of the methods were total cholesterol - cholesterol oxidase-peroxidase method; TGs -enzymatic, colorimetric method (GPO/PAP) with glycerol phosphate oxidase and 4-aminophenazone; HDL-cholesterol - homogeneous enzymatic colorimetric assay; and direct LDL cholesterol - the homogeneous enzymatic colorimetric assay: This automated method for direct LDL-cholesterol estimation is based on micellar solubilization of LDL-cholesterol by a nonionic detergent and the interaction of a sugar compound and lipoproteins (VLDL and chylomicrons). Biorad internal and external controls were run for total cholesterol, TGs, HDL and LDL cholesterol. Friedewalds calculated LDL was calculated by the formula: LDL cholesterol = Total cholesterol − HDL cholesterol − TGs/5 (VLDL cholesterol).

Statistical analysis

Data were entered into Microsoft Office Excel 2007. Categorical data were reported as frequency and continuous data were reported as mean and standard deviation. Paired t-test was used to test the difference in LDL concentration obtained by the direct method and Friedewalds calculated method. The level of significance was taken as P < 0.05 and two-sided. Scatter plot was used to represent the correlation between the two methods.

Data were categorized into three groups based on the TG levels [Table 1].
Table 1: Categorization of groups based on Triglyceride values


Click here to view



   Results Top


The study group consisted of 248 patients, 151 were males and 97 were females. [Table 2] indicates there was no statistical difference between direct LDL values and Friedewalds calculated LDL values (P = 0.140). [Table 3] shows there is no statistical difference between direct LDL values and Friedewalds calculated LDL at different ranges of TGs, ≤ 200 mg/dl (P = 0.47), 201-300 mg/dl (P = 0.32) and 301-400 mg/dl (P = 0.22).[Table 4] shows Pearson correlation which indicates good correlation between direct LDL and Friedewalds calculated LDL (correlation coefficient - 0.98). [Figure 1] indicates Scatter plot representing good correlation between direct LDL and Friedewalds calculated LDL with correlation coefficient of 0.98. [Figure 2] indicates Scatter plot which indicates good correlation between direct LDL and Friedewalds calculated LDL at TGs < 200 mg/dl with a correlation coefficient of 0.982. [Figure 3] indicates Scatter plot representing good correlation between direct LDL and Friedewalds calculated LDL at TGs 201-300 mg/dl with correlation coefficient of 0.964. [Figure 4] indicates Scatter plot representing good correlation between direct LDL and Friedewalds calculated LDL at TGs 301-400 mg/dl with correlation coefficient of 0.968.
Figure 1: Scatter plot representing the correlation between Direct LDL and Friedewalds calculated LDL at Triglycerides Less than 400 mg/dl (r = 0.981, r2 = 0.963)

Click here to view
Figure 2: Scatter plot representing the correlation between Direct LDL and Friedewalds calculated LDL at Triglycerides < 200 mg/dl (r = 0.982, r2 = 0.966)

Click here to view
Figure 3: Scatter plot representing the correlation between Direct LDL and Friedewalds calculated LDL at Triglycerides 201 to 300 mg/dl (r = 0.981, r2 = 0.964)

Click here to view
Figure 4: Scatter plot representing the correlation between Direct LDL and Friedewalds calculated LDL at Triglycerides 301 to 400 mg/dl (r = 0.968, r2 = 0.938)

Click here to view
Table 2: Comparison between direct LDL method and Friedewalds calculated LDL (n=248)

Click here to view
Table 3: Comparison between direct LDL method and Friedewalds calculated LDL at different serum level of TG (mg/dl)


Click here to view
Table 4: Pearson correlation between Direct LDL and Friedewalds calculated LDL


Click here to view


Person correlation showed that there exists good correlation between direct LDL versus Friedewalds formula (correlation coefficient = 0.98) [Table 4].


   Discussion Top


The primary target for diagnosis and management of hypercholesterolemia is LDL cholesterol as per NCEP Adult Treatment Panel report. [19] Hence, accurate reporting of LDL cholesterol is utmost important. In this study, there was no significant difference between the overall mean of direct LDL cholesterol with that of Friedewalds calculated LDL cholesterol [Table 2]. There was no significant difference between direct LDL and Friedewalds LDL at different TG levels ranging below 200 mg/dl, 201-300 mg/dl, and 301-400 mg/dl [Table 3]. Sudha et al. observed that Friedewalds calculated LDL were lower when compared to direct LDL with TG more than 180 mg/dl. [18] Boshtam et al. observed in their study that Friedewalds method overestimated LDL cholesterol by 7 mg/dl when compared to direct LDL method. [15] Kapoor R et al. observed that Friedewalds LDL method underestimated LDL cholesterol by 10.39% in comparison with direct LDL method. [20] Martin et al. observed that Friedewalds formula underestimated LDL cholesterol especially when TG value is >150 mg/dl. [16] Knopfholz et al. observed no significant difference between direct LDL and Friedewalds LDL at TGs below 150 mg/dl and above 150 mg/dl which was comparable to findings of this study. [21] Kannan et al. observed Friedewalds calculated LDL underestimated LDL cholesterol in comparison to direct LDL method. [17]

Direct LDL homogeneous assays are not free from limitations. They exhibit a negative bias as observed in studies done by Rifai et al. and this may result in placing a patient into low risk who actually belongs to high-risk hypercholesterolemia. [22],[23] Nauck et al. in their study observed, direct LDL method has no advantage when compared to calculated LDL method and recommended further validation for direct homogeneous methods. [8] Miller et al.in their study observed no advantage of direct LDL method in comparison to calculated LDL method at TG value below 400 mg/dl. [24] Mora et al. observed in their study the nonassociation of direct LDL with Friedewalds LDL in nonfasting samples and they could not demonstrate any advantage of direct LDL in comparison to Friedewalds calculated LDL. They also stated using direct LDL may misclassify the patients into low-risk NCEP category because the results of direct LDL were 5-10 mg/dl lower when compared to Friedewalds calculated LDL. [25] Gazi et al. observed Friedewalds calculated LDL was accurate for any value of TG below 400 mg/dl. [26] In this study, we observed a similar finding since the LDL cholesterol calculated by Friedewalds formula correlated well with direct LDL at TGs below 400 mg/dl [Figure 1], [Figure 2], [Figure 3] and [Figure 4]. Choi et al. observed that direct LDL values were 5% higher than calculated LDL and in diabetics, the difference was much higher. [27] Sudha et al. observed Friedewalds calculated LDL method underestimated LDL levels in comparison to direct method and they concluded that direct LDL method is better than Friedewalds calculated LDL in diabetics. [28] Chatterjee and Mendez observed there was a good correlation between Friedewalds calculated LDL and direct LDL method which is in agreement with the findings of the present study. [29] Lindsey et al. observed Friedewalds calculated LDL underestimated LDL levels by 20 mg/dl when compared to direct LDL method. [30] Kaur observed there was no significant difference between the LDL values measured by direct LDL method and Friedewalds calculated method in patients with metabolic syndrome. [31]

Friedewalds calculated LDL cannot be employed in individuals with TG value more than 400 mg/dl. Dansethakul et al. derived a new formula which correlated well with direct LDL values at TGs higher than 400 mg/dl. [32] Chaudhari et al. observed 38.2% of the study group were classified as high-risk group when LDL was estimated by direct LDL method and 24.9% were classified as high risk when LDL was calculated by Friedewalds calculated LDL. [33] Cordova et al. observed Friedewalds calculated LDL showed a positive bias at TG level <150 mg/dl and at TG level between 301 and 400 mg/dl, Friedewalds calculated LDL showed a negative bias in comparison to direct LDL. [34] Krishnaveni and Gowda observed Friedewalds calculated LDL correlated well with direct LDL except at TG level below 100 mg/dl and they observed at TG below 100 mg/dl, Anandaraja's calculated LDL performed better than Friedewalds calculated LDL. [35] Charuruks and Milintagas observed in their study, direct LDL to be more accurate and precise than Friedewalds calculated LDL and they suggested direct LDL method to be used in individuals with TG level > 200 mg/dl. [36] Ashour et al. observed in their study, there was no significant difference between Friedewalds calculated LDL and direct LDL at TG concentrations below 100 mg/dl but the LDL values obtained by Friedewalds equation was significantly lower when compared to direct LDL method at TG concentrations between 101-200 mg/dl and 201-300 mg/dl which is not in agreement with the findings of this study. [37] Mohan et al. observed in their study underestimation of LDL of 20-25 mg/dl by Friedewalds calculated LDL when compared to direct LDL method at TG between the range of 300-400 mg/dl. [38] Lee et al. observed LDL cholesterol measured by direct LDL method was significantly lower than Friedewalds calculated LDL and differences in the LDL cholesterol concentrations had no relation with TG concentrations. [39] Gasko observed Anandaraja's calculated LDL correlated better than Friedewalds calculated LDL with direct LDL in a Brazilian population. [40] Nakanishi et al. observed the original Friedewalds calculated LDL correlated best with direct LDL levels in comparison to modified Friedewalds formula and they suggested the chances of error in Calculated LDL increases with increase in TGs. [41] Teerakanchana et al. observed a high bias of 20.9 mg/dl at TGs between 301 and 400 mg/dl and a lower bias at TGs below 300 mg/dl with Friedewalds calculated LDL in comparison to direct LDL. [42] Sahu et al. observed a significant difference between direct LDL and Friedewalds calculated LDL at TG values below 300 mg/dl and there was no signifi cant difference at TG values above 300 mg/dl. According to Sahu et al., the possible explanation for such a result could be the masking or removal of LDL cholesterol due to the detergent used in direct method. [43] The sample size of this study was only 248 which is the limitation of the present study.


   Conclusion Top


Friedewalds Formula can be used to estimate LDL cholesterol, and direct LDL should be employed only in those cases wherein Friedewalds formula cannot be used like nonfasting samples, patients with TGs more than 400 mg/dl, disorders related to lipoproteins (Type III hyperlipoproteinemia) and secondary hyperlipoproteinemias.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

 
   References Top

1.
Heart Protection Study Collaborative Group. MRC/BHF Heart Protection Study of cholesterol lowering with simvastatin in 20,536 high-risk individuals: A randomised placebo-controlled trial. Lancet 2002;360:7-22.  Back to cited text no. 1
    
2.
Baigent C, Keech A, Kearney PM, Blackwell L, Buck G, Pollicino C, et al. Efficacy and safety of cholesterol-lowering treatment: Prospective meta-analysis of data from 90,056 participants in 14 randomised trials of statins. Lancet 2005;366:1267-78.  Back to cited text no. 2
    
3.
Gordon T, Kannel WB, Castelli WP, Dawber TR. Lipoproteins, cardiovascular disease, and death. The Framingham study. Arch Intern Med 1981;141:1128-31.  Back to cited text no. 3
    
4.
Grundy SM, Cleeman JI, Merz CN, Brewer HB Jr, Clark LT, Hunninghake DB, et al. Implications of recent clinical trials for the National Cholesterol Education Program Adult Treatment Panel III guidelines. Circulation 2004;110:227-39.  Back to cited text no. 4
    
5.
Randomised trial of cholesterol lowering in 4444 patients with coronary heart disease: The Scandinavian Simvastatin Survival Study (4S). Lancet 1994;344:1383-9.  Back to cited text no. 5
    
6.
Brown G, Albers JJ, Fisher LD, Schaefer SM, Lin JT, Kaplan C, et al. Regression of coronary artery disease as a result of intensive lipid-lowering therapy in men with high levels of apolipoprotein B. N Engl J Med 1990;323:1289-98.  Back to cited text no. 6
    
7.
Colpo A. LDL cholesterol: Bad cholesterol, or bad science? J Am Physicians Surg 2005;10:83-9.  Back to cited text no. 7
    
8.
Nauck M, Warnick GR, Rifai N. Methods for measurement of LDL-cholesterol: A critical assessment of direct measurement by homogeneous assays versus calculation. Clin Chem 2002;48:236-54.  Back to cited text no. 8
    
9.
Kamal AH, Hossain M, Chowdhury S, Mahmud NU. A comparison of calculated with direct measurement of low density lipoprotein cholesterol level. J Chittagong Med Coll Teach Assoc 2009;20:19-23.  Back to cited text no. 9
    
10.
Friedewald WT, Levy RI, Fredrickson DS. Estimation of the concentration of low-density lipoprotein cholesterol in plasma, without use of the preparative ultracentrifuge. Clin Chem 1972;18:499-502.  Back to cited text no. 10
    
11.
Bachorik PS, Ross JW. National Cholesterol Education Program recommendations for measurements of low-density lipoprotein cholesterol: Executive summary. National Cholesterol Education Program Working Group on Lipoprotein Measurements. Clin Chem 1995;41:1414-20.  Back to cited text no. 11
    
12.
Hirany S, Li D, Jialal I. A more valid measurement of low-density lipoprotein cholesterol in diabetic patients. Am J Med 1997;102:48-53.  Back to cited text no. 12
    
13.
Nauck M, Krämer-Guth A, Bartens W, März W, Wieland H, Wanner C. Is the determination of LDL cholesterol according to Friedewald accurate in CAPD and HD patients? Clin Nephrol 1996;46:319-25.  Back to cited text no. 13
    
14.
Matas C, Cabré M, La Ville A, Prats E, Joven J, Turner PR, et al. Limitations of the Friedewald formula for estimating low-density lipoprotein cholesterol in alcoholics with liver disease. Clin Chem 1994;40:404-6.  Back to cited text no. 14
    
15.
Boshtam M, Ramezani MA, Naderi G, Sarrafzadegan N. Is Friedewald formula a good estimation for low density lipoprotein level in Iranian population? J Res Med Sci 2012;17:519-22.  Back to cited text no. 15
    
16.
Martin SS, Blaha MJ, Elshazly MB, Brinton EA, Toth PP, McEvoy JW, et al. Friedewald-estimated versus directly measured low-density lipoprotein cholesterol and treatment implications. J Am Coll Cardiol 2013;62:732-9.  Back to cited text no. 16
    
17.
Kannan S, Mahadevan S, Ramji B, Jayapaul M, Kumaravel V. LDL-cholesterol: Friedewald calculated versus direct measurement-study from a large Indian laboratory database. Indian J Endocrinol Metab 2014;18:502-4.  Back to cited text no. 17
    
18.
Sudha K, Prabhu KA, Hegde A, Marathe A, Kumar KA. Effect of serum triglycerides on LDL estimation by Friedewald formula and direct assay: A laboratory based study. Int J Biomed Res 2015;6:189-91.  Back to cited text no. 18
    
19.
Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults. Executive summary of the third report of the national cholesterol education program (NCEP) expert panel on detection, evaluation, and treatment of high blood cholesterol in adults (Adult Treatment Panel III). JAMA 2001;285:2486-97.  Back to cited text no. 19
    
20.
Kapoor R, Chakraborty M, Singh N. A leap above Friedewald formula for calculation of low-density lipoprotein-cholesterol. J Lab Physicians 2015;7:11-6.  Back to cited text no. 20
[PUBMED]  Medknow Journal  
21.
Knopfholz J, Disserol CC, Pierin AJ, Schirr FL, Streisky L, Takito LL, et al. Validation of the friedewald formula in patients with metabolic syndrome. Cholesterol 2014;2014:261878.  Back to cited text no. 21
    
22.
Rifai N, Iannotti E, DeAngelis K, Law T. Analytical and clinical performance of a homogeneous enzymatic LDL-cholesterol assay compared with the ultracentrifugation-dextran sulfate-Mg2+method. Clin Chem 1998;44(6 Pt 1):1242-50.  Back to cited text no. 22
    
23.
Yu HH, Markowitz R, De Ferranti SD, Neufeld EJ, Farrow G, Bernstein HH, et al. Direct measurement of LDL-C in children: Performance of two surfactant-based methods in a general pediatric population. Clin Biochem 2000;33:89-95.  Back to cited text no. 23
    
24.
Miller WG, Waymack PP, Anderson FP, Ethridge SF, Jayne EC. Performance of four homogeneous direct methods for LDL-cholesterol. Clin Chem 2002;48:489-98.  Back to cited text no. 24
    
25.
Mora S, Rifai N, Buring JE, Ridker PM. Comparison of LDL cholesterol concentrations by Friedewald calculation and direct measurement in relation to cardiovascular events in 27,331 women. Clin Chem 2009;55:888-94.  Back to cited text no. 25
    
26.
Gazi I, Tsimihodimos V, Filippatos TD, Saougos VG, Bairaktari ET, Tselepis AD, et al. LDL cholesterol estimation in patients with the metabolic syndrome. Lipids Health Dis 2006;5:8.  Back to cited text no. 26
    
27.
Choi SY, Park HE, Kim MK, Shin CS, Cho SH, Oh BH. Difference between calculated and direct-measured low-density lipoprotein cholesterol in subjects with diabetes mellitus or taking lipid-lowering medications. J Clin Lipidol 2012;6:114-20.  Back to cited text no. 27
    
28.
Sudha K, Prabhu A, Kiran AM, Marathe A, Hegde A. Validation of the Friedewald formula in type II diabetes mellitus: An Indian perspective study. Int J Biomed Adv Res 2015;6:103-6.  Back to cited text no. 28
    
29.
Chatterjee S, Mendez D. A comparative and correlative study of direct LDL assay with Friedewald's formula in rural Kolar population. J Clin Biomed Sci 2011;1:158-63.  Back to cited text no. 29
    
30.
Lindsey CC, Graham MR, Johnston TP, Kiroff CG, Freshley A. A clinical comparison of calculated versus direct measurement of low-density lipoprotein cholesterol level. Pharmacotherapy 2004;24:167-72.  Back to cited text no. 30
    
31.
Kaur J. Use of Friedewalds equation for dyslipidemia in metabolic syndrome. Int J Med 2014;2:36-9.  Back to cited text no. 31
    
32.
Dansethakul P, Thapanathamchai L, Saichanma S, Worachartcheewan A, Pidetcha P. Determining a new formula for calculating low-density lipoprotein cholesterol: Data mining approach. EXCLI J 2015;14:478-83.  Back to cited text no. 32
    
33.
Chaudhari RK, Rajendra KC, Khan SA, Lal Das BK, Majhi S, Lamsal M, et al. Friedewald's method underestimates LDL-cholesterol even at lower range of triglyceride. Res J Pharm Biol Chem Sci 2015;6:787-92.  Back to cited text no. 33
    
34.
Cordova CM, Schneider CR, Juttel ID, Cordova MM. Comparison of LDL-cholesterol direct measurement with the estimate using the Friedewald formula in a sample of 10,664 patients. Arq Bras Cardiol 2004;83:482-7; 476-81.  Back to cited text no. 34
    
35.
Krishnaveni P, Gowda VM. Assessing the validity of Friedewald's formula and Anandraja's formula for serum LDL-cholesterol calculation. J Clin Diagn Res 2015;9:BC01-4.  Back to cited text no. 35
    
36.
Charuruks N, Milintagas A. Evaluation of calculated low-density lipoprotein against a direct assay. J Med Assoc Thai 2005;88 Suppl 4:S274-9.  Back to cited text no. 36
    
37.
Ashour S, Eljamil, Elhenshiri YS, Etekbali ET, Gimil GS. Significant differences between LDL-cholesterol levels obtained by Friedewald formula and a direct method. Open Conf Proc J 2012;3:59-62.  Back to cited text no. 37
    
38.
Mohan V, Priyadarshini KS, Shetty HV, Usha SM. Comparison of the values of low density lipoprotein by the direct and indirect methods (Friedewald equation). Int J Recent Trends Sci Technol 2015;14:534-6.  Back to cited text no. 38
    
39.
Lee SY, Hahm SK, Park JA, Choi SK, Yoon JY, Choi SH, et al. Measuring low density lipoprotein cholesterol: Comparison of direct measurement by hisens reagents and Friedewald estimation. Korean J Fam Med 2015;36:168-73.  Back to cited text no. 39
    
40.
Gasko R. Low-density lipoprotein cholesterol estimation by the Anandaraja's formula - Confirmation. Lipids Health Dis 2006;5:18.  Back to cited text no. 40
    
41.
Nakanishi N, Matsuo Y, Yoneda H, Nakamura K, Suzuki K, Tatara K. Validity of the conventional indirect methods including Friedewald method for determining serum low-density lipoprotein cholesterol level: Comparison with the direct homogeneous enzymatic analysis. J Occup Health 2000;42:130-7.  Back to cited text no. 41
    
42.
Teerakanchana T, Puavilai W, Suriyaprom K, Tungtrongchitr R. Comparative study of LDL-cholesterol levels in Thai patients by the direct method and using the Friedewald formula. Southeast Asian J Trop Med Public Health 2007;38:519-27.  Back to cited text no. 42
    
43.
Sahu S, Chawla R, Uppal B. Comparison of two methods of estimation of low density lipoprotein cholesterol, the direct versus Friedewald estimation. Indian J Clin Biochem 2005;20:54-61.  Back to cited text no. 43
    


    Figures

  [Figure 1], [Figure 2], [Figure 3], [Figure 4]
 
 
    Tables

  [Table 1], [Table 2], [Table 3], [Table 4]


This article has been cited by
1 Novel markers of endothelial dysfunction in hepatitis C virus-related cirrhosis: More than a mere prediction of esophageal varices
Amr Shaaban Hanafy,Mohamed Abdel Khalik Basha,Fady Maher Wadea
World Journal of Hepatology. 2020; 12(10): 850
[Pubmed] | [DOI]
2 Impact of glucose and lipid markers on the correlation of calculated and enzymatic measured low-density lipoprotein cholesterol in diabetic patients with coronary artery disease
Qiu-Ting Dong,Ying Gao,Na-Qiong Wu,Yuan-Lin Guo,Cheng-Gang Zhu,Sha Li,Hui-Hui Liu,Ye-Xuan Cao,Hui-Wen Zhang,Xi Zhao,Geng Liu,Qian Dong,Jian-Jun Li
Journal of Clinical Laboratory Analysis. 2018; : e22399
[Pubmed] | [DOI]
3 Prevención en diabetes mellitus y riesgo cardiovascular: enfoque médico y nutricional
Análida Elizabeth Pinilla-Roa,María Del Pilar Barrera-Perdomo
Revista de la Facultad de Medicina. 2018; 66(3): 459
[Pubmed] | [DOI]



 

Top
 
 
  Search
 
    Similar in PUBMED
   Search Pubmed for
   Search in Google Scholar for
 Related articles
    Access Statistics
    Email Alert *
    Add to My List *
* Registration required (free)  

 
  In this article
    Abstract
   Introduction
    Materials and Me...
   Results
   Discussion
   Conclusion
    References
    Article Figures
    Article Tables

 Article Access Statistics
    Viewed2434    
    Printed20    
    Emailed0    
    PDF Downloaded262    
    Comments [Add]    
    Cited by others 3    

Recommend this journal