The effect of time and temperature variables on routine coagulation tests.

Author(s): Adcock D, Kressin D, Marlar RA

Publication: Blood Coagul Fibrinolysis, 1998, Vol. 9, Page 463-70

PubMed ID: 9818995 PubMed Review Paper? No

Purpose of Paper

Conclusion of Paper

Studies

1. Study Purpose

   The purpose of this study was to determine the effects of oral anticoagulant therapy and storage of blood or plasma at room temperature or on ice on PT and APTT in normal subjects and hospitalized patients.

   Summary of Findings:

   PT changed less than 10% after storage of whole blood or plasma at room temperature or on ice for up to 24 h. APTT increased steadily over the 24 h period in specimens from healthy subjects (8.3-16.7%), and hospital patients not receiving unfractionated heparin (9.6-12.6%), but most changes were less than 10% until 8 h and no consistent effects of storage temperature were found. In patients receiving unfractionated heparin, APTT decreased rapidly over the 24 h period when stored as whole blood (33.1-35.6%) but decreased only slightly when plasma was stored (4.4-10.6%). Importantly, the effect of whole blood storage at room temperature in patients receiving unfractionated heparin could be observed as early as 2 h, but no effect was seen until at least 4 h when whole blood specimens were stored on ice. In conclusion, blood and plasma specimens from patients not receiving heparin may be stored at 4 degrees C or room temperature for up to 8 h prior to analysis, but for patients receiving heparin, specimens must be centrifuged within 1 h at room temperature or within 4 h at 4 degrees C.

   Biospecimens

   • Bodily Fluid - Blood
   • Bodily Fluid - Plasma

   Preservative Types

   • None (Fresh)

   Diagnoses:

   • Normal
   • Other diagnoses

   Platform:

   Analyte	Technology Platform
   Morphology	Hematology/ auto analyzer

   Pre-analytical Factors:

   Classification	Pre-analytical Factor	Value(s)
   Preaquisition	Other drugs	No anticoagulant therapy Coumadin Unfractionated heparin
   Preaquisition	Diagnosis/ patient condition	Normal Hospitalized patient
   Storage	Storage temperature	On ice Room temperature
   Storage	Storage duration	Less than 1 h 4 h 6 h 8 h 24 h
   Biospecimen Aliquots and Components	Blood and blood products	Plasma Whole blood
   Biospecimen Aliquots and Components	Centrifugation	Centrifugation delays investigated

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