Elimination of bilirubin interference on determination of serum N-acetyl-β-hexosaminidase activity

Abstract

Aim: Elimination interference of bilirubin on determination serum N-acetyl-β-hexosaminidase (HEX) activity. Material and Methods: We determined HEX activity in sera without and with exogenous bilirubin (4.3 mg/dL) using unmodified and modified method. Modification consists in subtraction absorbance of reaction mixture without substrate, from absorbance of reaction mixture incubated with substrate. Results: HEX activity (nKat/L) amounted: 179.7±74.6 without and 291.4±77.9 with exogenous bilirubin (standard method); 160.5±69.7 without and 164.9±76.8 with exogenous bilirubin (modified method). Correlation coefficient between results of HEX determination in serum without bilirubin and with exogenous bilirubin, obtained with modified method was 0.997. Conclusion: Exogenous bilirubin (4.3 mg/dL) significantly overestimates (p ≤0.001) HEX activity in blood serum determined by the standard method. Proposed modification eliminates interference of bilirubin on determination of HEX activity in blood serum.