title: Utility of in vitro closure time test for evaluating platelet-related primary hemostasis in dialysis patients.
abstract: BACKGROUND
  The platelet aggregation and skin bleeding time (SBT) tests currently used for assessment of hemostasis impairment in dialysis patients have important disadvantages. The authors explored the utility of a novel in vitro closure time test (PFA-100, platelet function analyzer) in which the process of platelet adhesion and aggregation after vascular injury is simulated in vitro in dialysis patients.
  
  
  METHODS
  Thirty-four long-term dialysis patients were included in the study with 30 healthy volunteers as the control group. In vitro closure time was compared with results from the platelet aggregation and SBT tests.
  
  
  RESULTS
  In vitro closure time identified more patients and fewer controls with hemostasis impairment. In the patient group, 60%, 40%, and 20%, and in the control group, 0%, 10% and 3% of persons were found to have hemostasis impairment as determined by in vitro closure time, platelet aggregation, and SBT, respectively. In addition, values for patients and controls were significantly different for in vitro closure time (P < 0.05) but not for platelet aggregation or SBT. Thus, closure time appears to be more sensitive and specific than the other 2 tests. No correlation was found between the 3 tests, either in patients or in controls. However, a high correlation (r = 0.73; P < 0.0001) was found between the 2 types of in vitro closure time test (collagen/epinephrine [CEPI] and collagen/adenosine diphosphate [CADP]) in patients and controls.
  
  
  CONCLUSIONS
  These results indicate that in vitro closure time can be a useful test for detecting platelet-related primary hemostasis defects in dialysis patients.
authors.affiliation: Department of Hematology, University Clinical Centre, Ljubljana, Slovenia. irena.zupan@kclj.si
authors.forename: Irena Preloznik
authors.initials: IP
authors.lastname: Zupan
authors.forename: Miso
authors.initials: M
authors.lastname: Sabovic
authors.forename: Barbara
authors.initials: B
authors.lastname: Salobir
authors.forename: Jadranka Buturovic
authors.initials: JB
authors.lastname: Ponikvar
authors.forename: Peter
authors.initials: P
authors.lastname: Cernelc
mesh_terms: D000368:Aged; D001760:Bleeding Time / Q000379:methods*; D005260:Female; D006487:Hemostasis / Q000502:physiology*; D006801:Humans; D066298:In Vitro Techniques; D007676:Kidney Failure, Chronic / Q000097:blood* / Q000628:therapy; D008297:Male; D008875:Middle Aged; D010974:Platelet Aggregation / Q000502:physiology*; D006435:Renal Dialysis; D018709:Statistics, Nonparametric