title: Detection of shortened activated partial thromboplastin times: an evaluation of different commercial reagents.
abstract: BACKGROUND
  Abnormally shortened activated partial thromboplastin times (aPTT) are associated with significantly increased risk of thrombotic disorders and in-hospital mortality. Shortened aPTTs have been related to increased levels of factor (F) VIII and thrombin-antithrombin complex (TAT). In the current study, four different commercial aPTT reagents were evaluated for their performance to detect shortened aPTTs.
  
  
  METHODS
  aPTT of 400 patients was determined using Actin-FS (Dade Behring), APTT-SP (Instrumentation Laboratory), Automated-APTT (bioMerieux) and Platelin-LS (bioMerieux) reagents. FVIII, FIX, FXI and TAT levels were measured in shortened and normal aPTT samples.
  
  
  RESULTS
  An association between shortened aPTTs and elevated levels of coagulation factors (FVIII, FIX and FXI) and thrombin generation (TAT) was found with all tested aPTT reagents. Method-comparison studies demonstrated good agreement between Instrumentation Laboratory and bioMerieux reagents. However, 53 to 59% of the patients with a shortened aPTT measured with Actin-FS reagent was determined as a normal aPTT with APTT-SP, Automated-APTT and Platelin-LS reagents. These patients had increased levels of FVIII, FIX and FXI and moderately increased levels of TAT.
  
  
  CONCLUSIONS
  Overall, an acceptable agreement between the different commercial reagents was found with respect to detection of short aPTTs. However, a disparity between some of reagents existed. Actin-FS reagent appeared to be more sensitive in inducing shortened aPTT reactions than APTT-SP, Automated-APTT and Platelin-LS reagents.
authors.affiliation: Department of Clinical laboratory, Sint Lucas Andreas Hospital Amsterdam, The Netherlands. e.tenboekel@slaz.nl
authors.forename: Edwin
authors.initials: E
authors.lastname: Ten Boekel
authors.forename: Martine
authors.initials: M
authors.lastname: Böck
authors.forename: Gert-Jan
authors.initials: GJ
authors.lastname: Vrielink
authors.forename: Robert
authors.initials: R
authors.lastname: Liem
authors.forename: Henriet
authors.initials: H
authors.lastname: Hendriks
authors.forename: Wim
authors.initials: W
authors.lastname: de Kieviet
mesh_terms: D000990:Antithrombin III; D001778:Blood Coagulation Disorders / Q000097:blood / Q000175:diagnosis; D005164:Factor IX / Q000032:analysis; D005169:Factor VIII / Q000032:analysis; D005172:Factor XI / Q000032:analysis; D006801:Humans; D007202:Indicators and Reagents; D010314:Partial Thromboplastin Time / Q000379:methods* / Q000706:statistics & numerical data; D010447:Peptide Hydrolases / Q000097:blood; D012016:Reference Values; D012307:Risk Factors; D013927:Thrombosis / Q000097:blood / Q000209:etiology
chemical_list: D007202:Indicators and Reagents; C046193:antithrombin III-protease complex; D000990:Antithrombin III; D005169:Factor VIII; D005164:Factor IX; D005172:Factor XI; D010447:Peptide Hydrolases