International Journal of Clinical Biochemistry and Research


ANALYTICAL METHOD COMPARISON OF ADVANCED OXIDATION PROTEIN PRODUCTS (AOPP) WITH MODIFIED AOPP


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Author Details: Sunaiba M, Avinash S.S, Arunkumar K, Malathi M, Shivashankara A. R, Ashwini K

Volume : 2

Issue : 1

Online ISSN : 2394-6377

Print ISSN : 2394-6369

Article First Page : 5

Article End Page : 12


Abstract

Introduction: AOPP (Advanced oxidation protein products) are the dityrosine containing protein cross linking products indicating the oxidised tyrosine residues of the plasma protein albumin, fibrinogen and lipoproteins. AOPP are elevated in oxidative stress and inflammation. Unlike AOPP the mAOPP estimation is not interfered by triglyeride levels.

Objective: Analytical method comparison of AOPP with mAOPP.
Materials and Methods: Measurement of AOPP involves the principle of spectrophotometric determination of oxidation of I- plasma AOPP under acidic condition by Witko Sarsat method. To remove the interference by the triglycerides especially seen in hypertriglyceridemia, the plasma was treated with lipid precipitating agent and the mAOPP were measured. In this study using pooled serum samples we compared the performance characteristics like precision, accuracy, linearity limit and reference range of AOPP assay with the mAOPP assay under our laboratory conditions as per CLIA guidelines of method validation.
Results and Discussion: The intrarun, intraday, interday and overall precision of AOPP (4.25%, 5.18%, 3.89%, 5%) was better than that of mAOPP (5.76%, 5.5%, 5.8%, and 5.8%). But on linear regression, mAOPP = 0.5×AOPP + 9.8 chloramine T equivalents (r2-0.62; p < 0.001) and the AOPP was 18% higher than mAOPP. In eutriglyceridemia however, mAOPP = 0.7xAOPP + 4.8 chloramine T equivalents (r2 = 0.75; p < 0.001) and the AOPP was only 14.5% higher. Also the correlation (r = 0.74) of AOPP – mAOPP levels with TG showed that the difference was significantly higher (p < 0.001) in the persons with higher TG levels clearly establishing the overestimation of AOPP.
Conclusion: Hence mAOPP may prove to be a better estimate of protein oxidation status and a better diagnostic and prognostic indicator compared to AOPP especially in hypertriglyceridemic patients.