Stability over time of immature platelet fraction and comparison between EDTA and citrated whole blood samples

Abstract

Background: Immature platelets (IP) are the youngest circulating platelets, released from megakaryocytes, and demonstrating increased dimensions, significant RNA content, and enhanced activity. Immature platelet research focuses on a differential diagnostic help in patients with thrombocytopenia. The objectives of this study were to compare the variability of IP in citrate and EDTA samples, and to determine stability over time.

Methods: Fifty-six patients were included for comparison between EDTA and citrate whole blood sample collection. Among the patients, 28 had thrombocytopenia (platelet count < 150G/L). Platelet measurement impedancemetry and fluorimetry were performed with Sysmex XN-9000. The immature platelet fraction (IPF) and absolute immature platelet count (A-IPC) were determined with a fluorescent method.

Results: The mean value of platelet count with fluorescence was, in EDTA sample, 215 ± 171 and, in citrate sample, 153 ± 118 G/L. No significant difference was observed between IPF between EDTA and citrate (7.74 ± 6.68% vs. 8.45 ± 7.37%, p = 0.69), respectively. With the Bland-Altman analysis, the mean difference in the EDTA sample, between 1 and 24 h, was 8.06 ± 6.96% and 8.73 ± 7.12% for IPF, whereas in the citrate sample, between 1 and 6 h, it was 8.60 ± 7.29% and 7.54 ± 6.97%, for IPF. Comparing 1 h EDTA sample with 6 h citrate sample, the variance ratio was 0.974 (95% CI: 0.864-1.084) in IPF.

Conclusions: We confirmed the potential to conduct IP measurements up to 24 h in the EDTA sample and IPF measurements in the citrate sample for up to 6 h. These results may be useful for the use of IPF, which is a promising parameter whose interest in clinical practice and standardization is not yet well defined.

Keywords: EDTA; citrate; delayed analysis; immature platelet count; immature platelet fraction.

FIGURE 1

Comparison of IPF‐delayed analysis in EDTA sample. Bland–Altman comparison between 1 and 0.5 h (A), 2 h (B), 4 h (C), 6 h (D) and 24 h (E).

FIGURE 2

Comparison of A‐IPC‐delayed analysis in EDTA sample. Bland–Altman comparison between 1 and 0.5 h (A), 2 h (B), 4 h (C), 6 h (D) and 24 h (E).

FIGURE 3

Stability over the time evaluation with Deming regression. Evaluation between 1 and 24 h in EDTA sample for IPF (A) and A‐IPC (B). Evaluation between 1 and 6 h in EDTA and citrate sample, respectively, for IPF (C) and A‐IPC (D). Evaluation between 1 and 24 h in the EDTA and citrate sample, respectively, for IPF (E).