title: Evaluation of the utility of serum prolidase as a marker for liver fibrosis.
abstract: BACKGROUND
  Liver dysfunction is common and often unrecognized. Liver biopsy is the gold standard in the assessment of liver fibrosis, but has disadvantages. We assessed the diagnostic accuracy of serum prolidase enzyme activity (SPA) in predicting the presence and degree of liver fibrosis, as compared with liver biopsy. Further, we evaluated the effect of hemolysis on measured SPA levels.
  
  
  METHODS
  We undertook a prospective case control study. Thirty eight outpatients without apparent liver illness and 20 patients with liver pathology scheduled to undergo liver biopsy had their SPA levels measured.
  
  
  RESULTS
  Patients undergoing liver biopsy had higher SPA levels (361 (268) IU/l [median (interquartile range)]) compared with controls (169 (160) (P < 0.001)). A SPA cutoff value of 200 IU/l yielded a sensitivity of 89%, specificity of 59%, an odds ratio of 11.5, negative predictive value of 92%, and a positive predictive value of 50%. Hemolysis causes an apparent increase in SPA levels.
  
  
  CONCLUSIONS
  Higher SPA levels in patients undergoing liver biopsies compared with controls may reflect the presence of liver fibrosis. SPA levels could not be used to stage the degree of fibrosis. SPA measurement may be useful in the diagnostic workup of suspected liver disease.
authors.affiliation: Division of Chemical Pathology, Department of Clinical Laboratory Sciences, University of Cape Town and National Health Laboratory Service, Cape Town, South Africa.
authors.forename: John C
authors.initials: JC
authors.lastname: Stanfliet
authors.affiliation: Division of Anatomical Pathology, Department of Clinical Laboratory Sciences, University of Cape Town and National Health Laboratory Service, Cape Town, South Africa.
authors.forename: Michael
authors.initials: M
authors.lastname: Locketz
authors.affiliation: Division of Chemical Pathology, Department of Clinical Laboratory Sciences, University of Cape Town and National Health Laboratory Service, Cape Town, South Africa.
authors.forename: Peter
authors.initials: P
authors.lastname: Berman
authors.affiliation: Division of Chemical Pathology, Department of Clinical Laboratory Sciences, University of Cape Town and National Health Laboratory Service, Cape Town, South Africa.|Department of Chemical Pathology, Faculty of Health Sciences, University of Pretoria and National Health Laboratory Service, Tshwane Academic Division, Pretoria, South Africa.
authors.forename: Tahir S
authors.initials: TS
authors.lastname: Pillay
mesh_terms: D001706:Biopsy; D004150:Dipeptidases / Q000097:blood*; D005260:Female; D006461:Hemolysis / Q000502:physiology; D006801:Humans; D008099:Liver / Q000473:pathology; D008103:Liver Cirrhosis / Q000097:blood* / Q000175:diagnosis*; D008297:Male; D011446:Prospective Studies; D012372:ROC Curve; D012189:Retrospective Studies
chemical_list: D004150:Dipeptidases; C022449:proline dipeptidase
keywords: diagnostic accuracy; liver pathology; prolidase; receiver-operator curve; screening