Clinically relevant differences in prothrombin time and INR values related to blood sample collection in plastic vs glass tubes.
Author(s): Fiebig EW, Etzell JE, Ng VL
Publication: Am J Clin Pathol, 2005, Vol. 124, Page 902-9
PubMed ID: 16416740 PubMed Review Paper? No
Purpose of Paper
Conclusion of Paper
Studies
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Study Purpose
The purpose of this study was to determine the effects of collection tube type on PT and INR in platelet-poor plasma. Plasma used for comparison of auto analyzers was stored at -70 degrees C for less than 20 days, on dry ice for 1 h, and then at -20 degrees C for less than 48 h or at -70 degrees C for the entire time prior to analysis.
Summary of Findings:
Specimens collected in plastic Vacuette or Vacutainer Plus tubes, as opposed to glass Monoject tubes, had significantly shorter PTs, and specimens with higher PTs showed the largest decreases (16-18%) compared to specimens in glass tubes. PTs measured in specimens collected in either type of plastic tube were similar. INR values were lower in specimens collected in either type of plastic tube versus glass tubes. The duration of warfarin therapy did not influence the differences in INRs observed between plastic and glass tubes, nor did the auto analyzer/reagent combination used for analysis.
Biospecimens
Preservative Types
- None (Fresh)
- Frozen
Diagnoses:
- Not specified
Platform:
Analyte Technology Platform Morphology Hematology/ auto analyzer Pre-analytical Factors:
Classification Pre-analytical Factor Value(s) Biospecimen Acquisition Type of collection container/solution 4.5 mL glass Monoject
3.5 mL plastic Vacuette
2.7 mL plastic Vacutainer Plus
Biospecimen Preservation Type of fixation/preservation Frozen
None (fresh)
Preaquisition Other drugs Warfarin therapy <6 weeks
Warfarin therapy >6 weeks
Unspecified/none
Hematology/ auto analyzer Specific Technology platform AMAX 190
MLA Electra 1400C analyzer
Hematology/ auto analyzer Specific Reaction solution Thrombomax HS
Thromboplastin-DS