To mix or not to mix venous blood samples collected in vacuum tubes?
Author(s): Parenmark A, Landberg E
Publication: Clin Chem Lab Med, 2011, Vol. 49, Page 2061-3
PubMed ID: 21899494 PubMed Review Paper? No
Purpose of Paper
The purpose of this paper was to determine the effects of mixing strategy after collection of blood on clinical chemistry and hematology analytes.
Conclusion of Paper
Activated partial thromboplastin time (APTT), aspartate aminotransferase (AST), bilirubin, creatinine kinase (CK), C-reactive protein (CRP), iron, potassium, free thyroxine (fT4), thyroid stimulating hormone (TSH), hematocrit, mean corpuscular volume (MCV), and hemoglobin levels, and leukocyte, platelet, and erythrocyte counts were not affected by mixing strategy. However, prothrombin time (PT), lactate dehydrogenase (LD) levels, and sodium levels were. Hemolysis index was increased in immediately mixed specimens compared to unmixed specimens in tubes containing separating gel and lithium heparin and in tubes containing citrate.
Studies
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Study Purpose
The purpose of this study was to determine the effects of mixing strategy after collection of blood on clinical chemistry and hematology analytes. Mixing was performed using a horizontal mixing tray for 1 min (15 inversions). After mixing (or not), all tubes were placed upright in a rack for 30 min prior to centrifugation.
Summary of Findings:
APTT, AST, bilirubin, CK, CRP, iron, potassium, fT4, TSH, hematocrit, MCV, and hemoglobin levels, and leukocyte, platelet, and erythrocyte counts were not affected by mixing strategy. However, PT showed a small but significant increase (average 2%, p<0.05) when tubes were not mixed compared to those that were mixed immediately or after 5 min. Further, plasma LD levels showed small but significant decreases (median 4.1%, p<0.05) when tubes were not mixed compared to those that were mixed immediately or after 5 min. In addition, sodium levels showed small but significant decreases (median 1%, p<0.05) in tubes that were not mixed or subjected to delayed mixing compared to those that were mixed immediately. Hemolysis index was increased in immediately mixed specimens compared to unmixed specimens in tubes containing separating gel and lithium heparin, and in tubes containing citrate.
Biospecimens
Preservative Types
- None (Fresh)
Diagnoses:
- Not specified
Platform:
Analyte Technology Platform Morphology Hematology/ auto analyzer Cell count/volume Hematology/ auto analyzer Protein Hematology/ auto analyzer Protein Clinical chemistry/auto analyzer Electrolyte/Metal Clinical chemistry/auto analyzer Peptide Clinical chemistry/auto analyzer Cell count/volume Spectrophotometry Pre-analytical Factors:
Classification Pre-analytical Factor Value(s) Biospecimen Aliquots and Components Biospecimen mixing Immediately inverted 15 times
5 min horizontal rest followed by inversion 15 times
6 min horizontal rest with no mixing
Biospecimen Acquisition Anticoagulant Citrate
Heparin