Mean platelet volume in patients with increased procalcitonin level

Procalcitonin (PCT) is the precursor of hormone calcitonin, which plays a metabolic role in calcium homeostasis [1]. Every tissue of human body has the potential to produce PCT, and serum level of PCT is usually markedly increased in conditions such as sepsis, systemic infection and severe inflammation [1, 2]. Mean platelet volume (MPV) is known to be associated with platelet reactivity and function [3–6]. MPV has also been investigated in several infectious diseases such as HIV, malaria and hepatitis B. However, it was not fully investigated in systemic bacterial infections. Therefore, we planned to evaluate MPV in patients with significantly increased PCT. The study group included 322 specimens from 268 Korean patients in which PCT levels were above 1.0 ng/ml (reference limit<0.046 ng/ml) from the Kyung Hee University Hospital, a tertiary teaching hospital, between August and December 2011. To include patients with definitive infection, we enrolled patients to show increased PCT level above 20 folds of the upper reference limit. For the control group, 311 subjects for medical check-ups were enrolled from the same hospital, who were also used as a control group in our previous studies [3, 4]. The mean age of patient group was 64.77 (range 0–94 years), and male-to-female ratio was 188:134. The spectrum of underlying diseases was broad, from malignancy to benign inflammation. Blood sampling was performed through venepuncture and MPV was measured using Ethylenediaminetetraacetic acid (EDTA)containing tubes in Advia 2120 (Siemens Healthcare Diagnostics Inc., Tarrytown, NY, USA) within 2 hours. Serum PCT was measured using Elecsys BRAHMS PCT (Roche, Mannheim, Germany). Statistical significance was analyzed using the independent sample Student’s t-test, and p values <0.05 were considered statistically significant. These statistical analyses were performed with MedCalc v11.6 (MedCalc Software, Mariakerke, Belgium) and Excel 2007 (Microsoft Corporation, Redmond, WA, USA). In the patient group, means for serum PCT was 9.58 ng/ml (range 1.0–100.0 ng/ml) and for serum CRP was 8.21 mg/dl (range <0.3–28.70 mg/dl), respectively (Table I). The mean MPV level was significantly higher in the patient group, which was 8.51 fl (95% confidence interval: 8.39–8.62 fl, p< 0.001, Figure 1). Correlation between MPV and PCT did