Optimization of 25% Sulfosalicylic Acid Protein-to-Creatinine Ratio for Screening of Low-Grade Proteinuria

Proteinuria is an important prognostic marker in the diagnosis and management of kidney diseases. Sulfosalicylic acid method (SSA) is a simple, low cost, qualitative test, widely used to assess proteinuria. The aim of this study was to optimize SSA test as a quantitative screening tool to assess pro...

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Main Authors: Ambulugala Gamage Rajika Greshamali Jinadasa, Lanka Acharige Shalka Madushan Srimantha, Indika Deepani Siriwardhana, Kalani Buddika Gunawardana, Anoja Priyadarshani Attanayake
Format: Article
Language:English
Published: Wiley 2021-01-01
Series:International Journal of Analytical Chemistry
Online Access:http://dx.doi.org/10.1155/2021/6688941
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author Ambulugala Gamage Rajika Greshamali Jinadasa
Lanka Acharige Shalka Madushan Srimantha
Indika Deepani Siriwardhana
Kalani Buddika Gunawardana
Anoja Priyadarshani Attanayake
author_facet Ambulugala Gamage Rajika Greshamali Jinadasa
Lanka Acharige Shalka Madushan Srimantha
Indika Deepani Siriwardhana
Kalani Buddika Gunawardana
Anoja Priyadarshani Attanayake
author_sort Ambulugala Gamage Rajika Greshamali Jinadasa
collection DOAJ
description Proteinuria is an important prognostic marker in the diagnosis and management of kidney diseases. Sulfosalicylic acid method (SSA) is a simple, low cost, qualitative test, widely used to assess proteinuria. The aim of this study was to optimize SSA test as a quantitative screening tool to assess proteinuria at lower excretory levels which would facilitate the screening and early diagnosis of renal impairment using protein-to-creatinine ratio (PCR). The study was conducted in two phases. In phase I, optimum SSA percentage to detect low-grade proteinuria was selected by comparing the performance of 3%, 6%, and 25% SSA methods in manual spectrophotometric analysis. In phase II, clinical applicability of the optimized method was evaluated using retained urine samples of patients with chronic kidney disease (CKD) assessed for urine protein by the pyrogallol red (PGR) method in a tertiary care hospital in Sri Lanka. Optimized 25% SSA protein-to-creatinine ratio (PCR) was compared with PGR PCR and albumin-to-creatinine ratio (ACR). Sensitivity, specificity, degree of agreement, correlation, and diagnostic accuracy were evaluated. Turbidimetric analysis using 25% SSA was linear in the range 3–50 mg/dL giving the highest analytical sensitivity. The test yielded a sensitivity of 86.5% and specificity of 96.5% and a degree of agreement of 5 mg/dL with the PGR method. Optimal cut-off for 25% SSA PCR in receiver operating characteristic analysis was 166 mg/g. Spearman’s correlation coefficient for 25% SSA PCR versus ACR was r = 0.823, p<0.0001, and for 25% SSA PCR versus PGR PCR was r = 0.913, p<0.0001. The 25% SSA PCR has a sensitivity of 92% against ACR, the current prognostic marker for proteinuria in patients with CKD. The 25% SSA test is a simple method, and it performs satisfactorily as a screening test with a cut-off for PCR optimized at 166 mg/g. The test merits further evaluation due to its low cost.
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spelling doaj-art-8d85528f018644e4ad346ae8524985a52025-02-03T05:49:16ZengWileyInternational Journal of Analytical Chemistry1687-87601687-87792021-01-01202110.1155/2021/66889416688941Optimization of 25% Sulfosalicylic Acid Protein-to-Creatinine Ratio for Screening of Low-Grade ProteinuriaAmbulugala Gamage Rajika Greshamali Jinadasa0Lanka Acharige Shalka Madushan Srimantha1Indika Deepani Siriwardhana2Kalani Buddika Gunawardana3Anoja Priyadarshani Attanayake4Department of Medical Laboratory Science, Faculty of Allied Health Sciences, University of Ruhuna, Galle, Sri LankaDepartment of Medical Laboratory Science, Faculty of Allied Health Sciences, University of Ruhuna, Galle, Sri LankaDepartment of Pathology, Faculty of Medicine, University of Ruhuna, Galle, Sri LankaDepartment of Medical Laboratory Science, Faculty of Allied Health Sciences, University of Ruhuna, Galle, Sri LankaDepartment of Biochemistry, Faculty of Medicine, University of Ruhuna, Galle, Sri LankaProteinuria is an important prognostic marker in the diagnosis and management of kidney diseases. Sulfosalicylic acid method (SSA) is a simple, low cost, qualitative test, widely used to assess proteinuria. The aim of this study was to optimize SSA test as a quantitative screening tool to assess proteinuria at lower excretory levels which would facilitate the screening and early diagnosis of renal impairment using protein-to-creatinine ratio (PCR). The study was conducted in two phases. In phase I, optimum SSA percentage to detect low-grade proteinuria was selected by comparing the performance of 3%, 6%, and 25% SSA methods in manual spectrophotometric analysis. In phase II, clinical applicability of the optimized method was evaluated using retained urine samples of patients with chronic kidney disease (CKD) assessed for urine protein by the pyrogallol red (PGR) method in a tertiary care hospital in Sri Lanka. Optimized 25% SSA protein-to-creatinine ratio (PCR) was compared with PGR PCR and albumin-to-creatinine ratio (ACR). Sensitivity, specificity, degree of agreement, correlation, and diagnostic accuracy were evaluated. Turbidimetric analysis using 25% SSA was linear in the range 3–50 mg/dL giving the highest analytical sensitivity. The test yielded a sensitivity of 86.5% and specificity of 96.5% and a degree of agreement of 5 mg/dL with the PGR method. Optimal cut-off for 25% SSA PCR in receiver operating characteristic analysis was 166 mg/g. Spearman’s correlation coefficient for 25% SSA PCR versus ACR was r = 0.823, p<0.0001, and for 25% SSA PCR versus PGR PCR was r = 0.913, p<0.0001. The 25% SSA PCR has a sensitivity of 92% against ACR, the current prognostic marker for proteinuria in patients with CKD. The 25% SSA test is a simple method, and it performs satisfactorily as a screening test with a cut-off for PCR optimized at 166 mg/g. The test merits further evaluation due to its low cost.http://dx.doi.org/10.1155/2021/6688941
spellingShingle Ambulugala Gamage Rajika Greshamali Jinadasa
Lanka Acharige Shalka Madushan Srimantha
Indika Deepani Siriwardhana
Kalani Buddika Gunawardana
Anoja Priyadarshani Attanayake
Optimization of 25% Sulfosalicylic Acid Protein-to-Creatinine Ratio for Screening of Low-Grade Proteinuria
International Journal of Analytical Chemistry
title Optimization of 25% Sulfosalicylic Acid Protein-to-Creatinine Ratio for Screening of Low-Grade Proteinuria
title_full Optimization of 25% Sulfosalicylic Acid Protein-to-Creatinine Ratio for Screening of Low-Grade Proteinuria
title_fullStr Optimization of 25% Sulfosalicylic Acid Protein-to-Creatinine Ratio for Screening of Low-Grade Proteinuria
title_full_unstemmed Optimization of 25% Sulfosalicylic Acid Protein-to-Creatinine Ratio for Screening of Low-Grade Proteinuria
title_short Optimization of 25% Sulfosalicylic Acid Protein-to-Creatinine Ratio for Screening of Low-Grade Proteinuria
title_sort optimization of 25 sulfosalicylic acid protein to creatinine ratio for screening of low grade proteinuria
url http://dx.doi.org/10.1155/2021/6688941
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