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Impact of Shaking EDTA, Citrate, or MgSO(4) Tubes on Platelet Count Results.

Author(s): Soulard M, Ketatni H, Visseaux C, Croix P, Cohen P

Publication: J Clin Med, 2024, Vol. 13, Page

PubMed ID: 39336837 PubMed Review Paper? No

Purpose of Paper

Conclusion of Paper

Studies

1. Study Purpose

   This study investigated the impact of storing K₂EDTA, citrate, and MgSO₄ blood tubes on a rotating disc for up to 3 h on platelet counts. Blood was collected from 87 patients (diagnosis not specified) into a K₂EDTA Vacutainer tube, then a Sodium Citrate Vacutainer tube and finally into a MgSO₄ S-Monovette Thromboexact tube. To exclude the presence of platelet clusters, blood smears were stained with SP10 and analyzed by light microscopy. Blood specimens with ≥5 agglutinated platelets/field in >3 of the 30 fields evaluated for any of the three anticoagulants were excluded from further study, which reduced the cohort size to specimens from only 70 patients. Platelets were counted using a Sysmex XN10 using both the impedance and fluorescence method within 30 min (baseline) and then placed on a rotating disc (20 revolutions/min) at a 45 degree incline. At each timepoint (15 min, 30 min, 60 min, 90 min, 120 min, 150 min, and 180 min), the tubes were placed in a vertical position for 10 min, inverted 10 times and analyzed before being returned to the rotating disc. The mean and pseudo-median percentage deviation (PMeD) for each time-point from baseline was compared to the desirable platelet bias of 4.5% from the European Federation of Clinical Chemistry and Laboratory Medicine (EFLM) to determine clinical significance. Statistical significance was calculated using a Wilcoxon two-side test when the PMeD was less than the desirable EFLM bias and a Wilcoxon 2-side sign test (Wilcoxon) when PMeD was greater than the desirable EFLM bias. The normality of the distribution was verified using the Shapiro–Wilk test. Confidence intervals of the mean and pseudo median were determined using Student’s t-test, and Tukey’s test, respectively.

   Summary of Findings:

   Platelet counts increased with agitation of EDTA tubes, with significant differences in PMeD observed after only 15 min of agitation using both the impedance and fluorescence analysis (P<0.0001, all timepoints for both); however, the difference in PMeD remained well below the desirable bias limit of 4.5% even after 180 min using both impedance and fluorescence (1.17% and 2.26%, respectively). In sodium citrate blood, platelet counts decreased with agitation, with clinically and statistically significant differences in PMeD observed after only 15 min of agitation using either impedance or fluorescence analysis (-10.55% and -12.36%, respectively, P<0.0001, both). For all timepoints, the bias in sodium citrate was larger when analyzed by impendence than fluorescence, and the slope of the regression lines were similar; however the Regression Through the Origin (RTO) slopes were almost twice that of the Ordinary Least Squares (OLS) regression (−115 × 10⁻⁴ versus −62 × 10⁻⁴ in impedance and −101 × 10⁻⁴ versus -58 x 10⁻⁴ in fluorescence). Further, the bias was greater when sodium citrate tubes were agitated for 180 min than in matched tubes that were held vertically for the same duration (-29.76% versus -15.6%). Similar to sodium citrate blood, platelet counts in MgSO₄ tubes decreased with agitation, with clinically significant differences in PMeD observed after only 15 min of agitation using either the impedance or fluorescence analysis (P<0.0001, both), but bias exceeded the desirable bias limit only after 60 min (-6.95% and -9.69%, respectively). Slope of the regression lines were slightly different when analyzed by impendence than fluorescence, regardless of if RTO or OLS was used (−73 × 10⁻⁴ versus −74 × 10⁻⁴ in impedance and −94 × 10⁻⁴ versus -95 x 10⁻⁴ in fluorescence). The bias was greater when blood in MgSO₄ tubes were agitated for 180 min than in matched tubes that were held vertically for the same duration (-33.18% versus -0.85%). The authors state that the decrease in platelet count corresponded to the increased appearance of platelet clusters in sodium citrate and MgSO₄ blood..

   Biospecimens

   • Bodily Fluid - Blood

   Preservative Types

   • None (Fresh)

   Diagnoses:

   • Not specified

   Platform:

   Analyte	Technology Platform
   Cell count/volume	Hematology/ auto analyzer

   Pre-analytical Factors:

   Classification	Pre-analytical Factor	Value(s)
   Storage	Storage duration	15 min 30 min 60 min 90 min 120 min 150 min 180 min
   Biospecimen Acquisition	Type of collection container/solution	K2EDTA Vacutainer Sodium citrate Vacutainer MgSO4 S-Monovette Thromboexact tube
   Storage	Type of storage container	K2EDTA Vacutainer Sodium citrate Vacutainer MgSO4 S-Monovette Thromboexact tube
   Hematology/ auto analyzer Specific	Technology platform	Fluorescence Impedance
   Storage	Storage conditions	15 min to 3 h on rotating disc 3 h vertical

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