Mean Platelet Volume, Platelet Distribution Width, and Platelet Count, in Connection With Immune Thrombocytopenic Purpura and Essential Thrombocytopenia

Eunyup Lee, MD; Miyoung Kim, MD; Kibum Jeon, MD; Jiwon Lee, MD; Jee-Soo Lee, MD; Han-Sung Kim, MD; Hee Jung Kang, MD; Young Kyung Lee, MD

Disclosures

Lab Med. 2019;50(3):279-285. 

In This Article

Results

Patient Profile

The distributions of age, sex, and measured CBC parameters, including Hb, MCVs, MCHCs, RDWs, WBCs, and PLTs, from the study subject individuals are summarized in Table 1.

Comparisons of PLT Indices (MPV and PDW) in Healthy Individuals and Patients With ITP and ET

MPV and PDW in ITP. The MPV in patients with ITP was 10.2 (8.6–11.0) fL, which was significantly higher than the 8.8 (8.4–9.3) fL observed in healthy individuals (P <.001) (Figure 1A). The PDW values in patients with ITP (66.3% [57.4%–70.1%]) were significantly higher than those in healthy individuals (50.5% [47.1%–55.3%]) (Figure 1B).

Figure 1.

Difference in platelet parameters among healthy individuals, patients with immune thrombocytopenic purpura (ITP), and patients with essential thrombocythemia (ET). A, Mean platelet volume (MPV) in patients with immune thrombocytopenic purpura (ITP) vs in healthy individuals. B, Platelet distribution width (PDW) in patients with essential thrombocythemia (ET) vs in healthy individuals.

MPV and PDW in ET. The MPV of patients with ET was significantly lower than that in patients with ITP and that in healthy individuals (8.3 [7.7–8.9] fL; P <.001) (Figure 1A). Further, patients with ET showed higher PDW values than healthy individuals (Figure 1B). However, patients with ET showed significantly lower PDW values than patients with ITP (54.1% [45.8%–60.0%] vs 66.3% [57.4%–70.1%]; P <.001).

Correlations Among MPV, PDW, and PLT Counts in ITP and ET

Patients with ITP. When patients with ITP were subdivided into 2 groups based on their PLT counts (<45 × 103/μL vs ≥ 45 × 103/μL), there was no statistically significant difference in MPV or PDW between the 2 groups (Table 2). On Spearman correlation analysis, neither MPV nor PDW showed any significant correlation with PLT counts (ρ = −0.129, P = .46 and ρ = −0.162, P = .35, respectively). The PDW and MPV were moderately correlated with each other (ρ= 0.458, P = .006).

Patients with ET. When patients with ET were subdivided into 2 groups according to their PLT counts (<770 × 103/μL or ≥ 770 × 103/μL), MPV and PDW were significantly lower in patients with ET who had PLT counts of 770 or greater × 103 per μL than in those with counts less than 770 × 103 per μL (Table 2). The mean MPVs were 8.5 (7.8–9.2) fL in patients with ET who had PLT counts less than 770 × 103 per μL and 8.1 (7.6–8.4) fL in those with counts of 770 or greater × 103 per μL (P = .04). In contrast, the PDWs were 57.1% (52.2%–64.3%) in patients with ET who had PLT counts greater than 770 × 103 per μL and 50.2% (41.7%–57.3%) in patients with counts of 770 or greater × 103 per μL (P= .008).

On Spearman correlation analysis, the MPV showed a weak negative correlation with PLT counts (ρ = −0.394; P = .006), as did the PDW (ρ = −0.492; P <.001). Also, the PDW and MPV values showed moderate positive correlation with each other (ρ = 0.609; P<.001).

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