INTRODUCTION: This study assessed diagnostic accuracy and optimal cut point of blood lead levels (BLLs) on serum proteins (total protein, albumin, globulin and albumin/globulin ratio) among workers exposed to Pb from Pb- battery plant.
METHODS: Diagnostic accuracy and optimal cut point value of BLLs on serum proteins among workers exposed to Pb was done using area under the curve (AUC) and coordinates of ROC curve.Study group consists of 176 male workers working in Pb-battery plant. Control group consist of 80 office workers with no occupational Pb-exposure. BLLs in subjects were estimated using atomic absorption spectrophotometer. Serum proteins (total protein & albumin) were determined using diagnostic kits.Serum globulin was calculated from total protein and albumin. A/G ratio was calculated from albumin and globulin levels.
RESULTS: AUC value reported as 0.626 (95% of CI=0.540–0.712; P=0.005) for serum total protein with cutoff value≤ 6.9 g/dL. Serum albumin the AUC value was 0.466 (95% of CI=0.344–0.587; P=0.574) with cutoff value ≤4.0 g/dL. AUC value of serum globulin was 0.625 (95% of CI=0.541–0.708, p=0.005) with cut off value ≤2.4g/dL. A/G ratio showed the AUC value of 0.606 (95% of CI=0.521–0.692; p=0.012) with cutoff value >1.5g/dL. Optimal cut point value of BLLs 25.5µg/dL was noted for serum total protein with 56% sensitivity and 51% specificity. BLLs value of 24.5 µg/dL was noted as optimal cut point for serum albumin through 44% sensitivity and 44% specificity. Serum globulin and A/G ratio has shown the 55% sensitivity and 55% specificity with 27.5 µg/dL BLLs as optimal cut point value.
DISCUSSION AND CONCLUSION: AUROC values of serum total protein, globulin and A/G ratio were found significant when compared to serum albumin and BLLs ranged from 24.5 - 27.5µg/dL were noted optimal cut point values for serum proteins. The findings of the study could be useful to set cutoff BLLs for serum protein markers in Pb-exposure.