title: Serum Basal Paraoxonase 1 Activity as an Additional Liver Function Test for the Evaluation of Patients with Chronic Hepatitis.
abstract: BACKGROUND
  The diagnostic accuracy of currently available standard panel of liver function tests is not satisfactory for the reliable diagnosis of chronic liver disorders. Earlier studies have reported that serum basal paraoxonase 1 (PON1) activity measurement may add a significant contribution to the liver function tests.
  
  
  OBJECTIVE
  To assess whether the measurement of serum basal paraoxonase 1 (PON1) activity would be useful as an index of liver function status in chronic hepatitis patients.
  
  
  METHODS
  The study included 50 chronic hepatitis patients and 50 apparently healthy controls based on inclusion & exclusion criteria. In all the subjects, standard liver function tests were analysed by using standard methods. Basal PON1 activity was estimated using spectrophotometric method by the hydrolysis of p-nitrophenylacetate. Student t-test, Pearson's correlation coefficient, diagnostic validity tests and ROC curve analysis were the methods used for the statistical analysis of the data.
  
  
  RESULTS
  The serum basal PON1 activity was significantly decreased in chronic hepatitis cases when compared to controls (p< 0.001). Also basal PON1 activity was positively correlated with serum total protein and albumin, and negatively correlated with serum total bilirubin, alanine amino transferase (ALT), and alkaline phosphatase (ALP) (p< 0.001) in chronic hepatitis cases but not in healthy controls. Diagnostic validity tests showed, basal PON1 activity was a better discriminator of chronic hepatitis than total protein, albumin and ALP with sensitivity of 68%, specificity of 100%, positive predictive value of 100% and negative predictive value of 75%. ROC curve analysis demonstrated highest diagnostic accuracy for ALT (AUC = 0.999) followed by PON1 (AUC = 0.990), total bilirubin (AUC = 0.977), ALP (AUC = 0.904), total protein (AUC = 0.790) and albumin (AUC = 0.595).
  
  
  CONCLUSIONS
  Diagnostic accuracy of serum PON1 activity is better than total bilirubin, total protein, albumin and ALP. PON1 activity measurement could significantly improve the current efficiency of a laboratory's evaluation of patients with suspected chronic hepatitis.
authors.affiliation: Assistant Professor, Department of Biochemistry, Belagavi Institute of Medical Sciences , Belagavi, Karnataka, India .
authors.forename: Anand K
authors.initials: AK
authors.lastname: Pyati
authors.affiliation: Associate Professor, Department of Biochemistry, Subbaiah Institute of Medical Sciences , Shimoga, Karnataka, India .
authors.forename: Chandrakanth K
authors.initials: CK
authors.lastname: Halappa
authors.affiliation: Post-Graduate Student, Department of Pedodontics and Preventive Dentistry, Navodaya Dental College , Raichur, Karnataka, India .
authors.forename: Sudharani A
authors.initials: SA
authors.lastname: Pyati
authors.affiliation: Assistant Professor, Department of Biochemistry, Raichur Institute of Medical Sciences , Raichur, Karnataka, India .
authors.lastname: Nagaraj
authors.affiliation: Assistant Professor, Department of Biochemistry, M R Medical College , Kalaburagi, Karnataka, India .
authors.forename: Vinod
authors.initials: V
authors.lastname: Wali
keywords: Alanine transaminase; Albumin; Alkaline phosphatase; Bilirubin; Chronic; Hepatitis; Human; PON1 protein