Monitoring oral anticoagulant treatment from plasma stored for up to 48 hours and frozen plasma.

Author(s): Grau E, Tenias JM, Olaso MA, Ferrando I, Juan MT, Pastor E, Perez A, Real E

Publication: Haematologica, 1999, Vol. 84, Page 633-6

PubMed ID: 10406906 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 storage temperature and duration and thromboplastin reagent and analyzer on PT, INR, and factor II, VII, IX, and X activity in plasma from patients on acenocoumarol therapy. Blood was collected into tubes containing 3.2% citrate, and plasma was analyzed immediately, refrigerated for 24 or 48 h before analysis, or frozen at -40 degrees C for less than 1 month before analysis.

   Summary of Findings:

   Only slight reductions in factor II, VII, IX, and X activity were noted when plasma was refrigerated for 24 h or frozen, but significant reductions in factor VII and IX activity were observed after 48 h or refrigeration compared to fresh plasma. Regardless of instrumentation or reagent, there were no significant differences in INRs between fresh plasma and plasma that had been refrigerated for 24 h or frozen. Correlations between INRs (calculated using PT) in fresh plasma and those of plasma that had been refrigerated for 24 or 48 h, or frozen for less than 1 month varied based on the instrumentation and thromboplastin reagent used. When Thromboplastin IS was used with the Sysmex CA-6000, correlations were very strong (0.94-0.98) between INRs of fresh plasma and refrigerated or frozen plasma. When Simplastin was used with the Thrombolyzer Chrom, correlations were very strong between INRs of fresh plasma and plasma refrigerated for 24 h (0.95) or frozen plasma (0.92), but only a modest correlation was observed between the INR or fresh plasma and plasma that had been refrigerated for 48 h (0.50). A similar phenomenon was observed when Thromborel was used with the ACL 6000, with correlations of 0.91, 0.55, and 0.98 between INRs or fresh plasma and those of plasma that had been refrigerated for 24 h, 48 h, or frozen, respectively. When Thromboplastin D+G was used with the ACL 6000, strong correlations were observed between INRs of fresh plasma and plasma that had been refrigerated for 24 h or 48 h (0.85 and 0.81, respectively), while a very strong correlation was observed between the INRs of fresh and frozen plasma (0.97).

   Biospecimens

   • Bodily Fluid - Plasma

   Preservative Types

   • Frozen
   • None (Fresh)
   • Other Preservative

   Diagnoses:

   • Other diagnoses

   Platform:

   Analyte	Technology Platform
   Morphology	Hematology/ auto analyzer
   Protein	Hematology/ auto analyzer

   Pre-analytical Factors:

   Classification	Pre-analytical Factor	Value(s)
   Preaquisition	Diagnosis/ patient condition	Atrial fibrillation Valvular prosthesis Cardiomyopathy Venous thromboembolism
   Biospecimen Preservation	Type of fixation/preservation	Frozen None (fresh) Refrigeration
   Storage	Storage temperature	2-8 degrees C -40 degrees C
   Storage	Storage duration	0 h 24 h 48 h <1 month
   Hematology/ auto analyzer Specific	Reaction solution	Thromboplastin IS Simplastin Thromborel Thromboplastin D+G
   Hematology/ auto analyzer Specific	Technology platform	Sysmex CA-6000 Thrombolyzer Chrom ACL 6000

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