Evaluation of effect of serum triglyceride and total cholesterol on calculated LDL levels.

Ms.Saranya  Sundaramoorthi; Dr. Subha   Palaneeswari M; Dr. Karthik  Shunmugavelu

doi:10.51168/sjhrafrica.v7i3.2521

Authors

Ms.Saranya Sundaramoorthi Assistant Professor, Department of biochemistry, PSP medical college hospital and research institute Tambaram Kanchipuram main road Oragadam Panruti Kanchipuram district Tamilnadu 631604 India.
Dr. Subha Palaneeswari M Assistant Professor, MD Biochemistry, PSP medical college hospital and research institute Tambaram Kanchipuram main road Oragadam Panruti Kanchipuram district Tamilnadu 631604 India
Dr. Karthik Shunmugavelu Assistant Professor, Department of Dentistry, PSP medical college hospital and research institute Tambaram Kanchipuram main road Oragadam Panruti Kanchipuram district Tamilnadu 631604 India.

DOI:

https://doi.org/10.51168/sjhrafrica.v7i3.2521

Keywords:

serum triglyceride, total cholesterol, low density lipoproteins, biochemistry, medical, research

Abstract

Background

Low-density lipoprotein cholesterol (LDL-C) is a key marker for cardiovascular risk assessment. The Friedewald formula is widely used for indirect LDL estimation; however, its accuracy is influenced by serum triglyceride (TG) and total cholesterol (TC) levels. This cross-sectional analytical study evaluated the effect of serum TG and TC on calculated LDL-C compared with direct measurement.

Materials and Methods:

A total of 495 fasting serum samples (normal, n=284; dyslipidemic, n=211) were analyzed. Lipid parameters, including total cholesterol, HDL-C, TG and direct LDL-C, were measured using an automated enzymatic method. Indirect LDL-C was calculated using the Friedewald formula. Samples were categorized into five groups based on TG and TC levels. Agreement between direct and calculated LDL-C was assessed using Pearson’s correlation and percentage bias.

Results:

A strong correlation between direct and calculated LDL-C was observed in groups with TG <400 mg/dL (r ranging from 0.94 to 0.95), while reduced correlation was noted at TG >400 mg/dL (r=0.871). The percentage of LDL-C underestimation increased with rising TG levels (6% in Group A to 100% in Group D). In contrast, samples with elevated TC (>200 mg/dL) demonstrated 54% overestimation. Variability and bias increased significantly at TG levels >250 mg/dL.

Conclusion:

The Friedewald formula shows reduced reliability with increasing triglyceride levels, particularly beyond 250 mg/dL and is unreliable at levels >400 mg/dL. Elevated total cholesterol also contributes to estimation errors.

Recommendation:

Direct LDL-C measurement should be preferred in patients with triglyceride levels >250 mg/dL or elevated total cholesterol to ensure accurate cardiovascular risk assessment.

Author Biographies

Ms.Saranya Sundaramoorthi, Assistant Professor, Department of biochemistry, PSP medical college hospital and research institute Tambaram Kanchipuram main road Oragadam Panruti Kanchipuram district Tamilnadu 631604 India.

Assistant Professor, Department of Biochemistry, PSP Medical College Hospital and Research Institute, Tamil Nadu, India. Research interests include clinical biochemistry and lipid metabolism.

Dr. Subha Palaneeswari M, Assistant Professor, MD Biochemistry, PSP medical college hospital and research institute Tambaram Kanchipuram main road Oragadam Panruti Kanchipuram district Tamilnadu 631604 India

M, MD (Biochemistry)
Assistant Professor, Department of Biochemistry, PSP Medical College Hospital and Research Institute, Tamil Nadu, India. Areas of interest include diagnostic biochemistry and metabolic disorders.

Dr. Karthik Shunmugavelu, Assistant Professor, Department of Dentistry, PSP medical college hospital and research institute Tambaram Kanchipuram main road Oragadam Panruti Kanchipuram district Tamilnadu 631604 India.

BDS, MDS (OMFP), MSc (London), MFDS (RCS England, RCPS Glasgow)
Assistant Professor, Department of Dentistry, PSP Medical College Hospital and Research Institute, Tamil Nadu, India. His research focuses on oral pathology, translational diagnostics and interdisciplinary clinical research.

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