Cancer Diagnosis Program | Biorepositories and Biospecimen Research Branch

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Integrity of serum samples is changed by modified centrifugation conditions.

Author(s): Miler M, Nikolac Gabaj N, Culej J, Unic A, Vrtaric A, Milevoj Kopcinovic L

Publication: Clin Chem Lab Med, 2019, Vol. 57, Page 1882-1887

PubMed ID: 31343976 PubMed Review Paper? No

Purpose of Paper

Conclusion of Paper

Studies

1. Study Purpose

   This study investigated the effects of centrifugation speed and duration used to obtain serum from whole blood on the hemolysis index and specimen result turnaround times in unmatched specimens. Venous specimens from participants of unknown health condition were collected in 4.5- or 6-mL Greiner Bio-O tubes with clot activator without a separator. Specimens collected over a 10-day period (n=5944) were centrifuged for 10 min at 2876 × g and results were used as reference. Specimens collected over additional 10-day periods were centrifuged at 2876 x g for 5 min (n=5024) or 7 min (n=4946) or at 4141 × g for 7 min (n=3919). After centrifugation, specimens were processed on an automated chemistry analyzer. Specimens with clot or leftover fibrin strands were recognized as aspiration errors and were re-centrifuged. The hemolysis index was calculated using four pairs of wavelengths (500/524 nm, 572/604 nm, 628/660 nm, and 524/804 nm) and serum with a hemolysis index of only 0.5 g/L was considered hemolyzed. The authors state that interference due to potassium concentration resulted in specimens reported as hemolyzed by the analyzer and thus hemolysis index was not calculated. Turnaround time was defined as the time from sample registration in the laboratory information system to the time of releasing results.

   Summary of Findings:

   There was a significantly higher number of specimens with leftover fibrin strands when centrifuged at the lower speed (2876 x g) for 5 min compared to reference specimens which were centrifuged at the same speed for 10 min (P=0.021) but specimens centrifuged for 7 min at either speed had comparable number of specimens with leftover fibrin strands to reference specimens (P=0.066 and 0.177, respectively). The number of specimens with a hemolysis index above 0.5 was significantly higher in all specimens analyzed compared to reference specimens, regardless of centrifugation speed and duration (P<0.05, all), but significance disappeared when the number of specimens noted as hemolyzed by the analyzer due to potassium interference was considered. Turnaround times differed significantly between all centrifugation conditions (P<0.001) with the shortest times for specimens centrifuged at the lower speed for 5 min and at the higher speed for 7 min (median of 32 min for both) compared to reference specimens (median 36 min). The 90% completion time was also reduced for all centrifugation conditions compared to the reference condition (45–47 min versus 50 min), but a significant reduction was observed only for specimens centrifuged at the higher speed (4141 x g) for 7 min when only the number of specimens exceeding a turnaround time of 60 min were considered (P=0.011).

   Biospecimens

   • Bodily Fluid - Serum
   • Bodily Fluid - Blood

   Preservative Types

   • None (Fresh)

   Diagnoses:

   • Not specified

   Platform:

   Analyte	Technology Platform
   Small molecule	Clinical chemistry/auto analyzer

   Pre-analytical Factors:

   Classification	Pre-analytical Factor	Value(s)
   Biospecimen Aliquots and Components	Centrifugation	Multiple durations compared Multiple speeds compared

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