Blood samples of patients and controls were obtained at 7:00 AM in the next morning of the day of admission (within 0–6 [n = 131], 6–12 [n = 62], 12–24 [n = 26], and 24–48 [n = 21] hours from symptom onset). Patients’ blood samples were collected in the ward bedside in 5-ml vacuum tubes containing 0.5 ml buffered sodium citrate. Plasma aliquots were collected within one hour after randomization and centrifuged at 4000 g for 10 min at ambient room temperature. Plasma was then frozen at −70C until assayed.
D-dimer concentration was measured with a particle-enhanced, immunoturbidimetric assay in a calibrated SYSMEX7000 analyzer (Sysmex Corporation, Hyogo, Japan). The normal range of morning plasma D-dimer concentration in our hospital laboratory is 0–0.55 mg/L, which is slightly higher than other laboratory (0.25 mg/L [6] (link)). The detection limit was 0.05 mg/L, and the dynamic range was from 0.07 to 35.2 mg/L. The intra-assay coefficient of variation [CV] and inter-assay CV were 1.5–3.4%, 2.6%–4.5%, respectively. Plasma levels of glucose, C-reactive protein (CRP), leucocyte count, prothrombin time (PT), activated partial thromboplastin time (APTT), thrombin time (TT) and fibrinogen (FBG) were also tested by standard method. For all measurements, levels that were not detectable were considered to have a value equal to the lower limit of detection of the assay.
D-dimer concentration was measured with a particle-enhanced, immunoturbidimetric assay in a calibrated SYSMEX7000 analyzer (Sysmex Corporation, Hyogo, Japan). The normal range of morning plasma D-dimer concentration in our hospital laboratory is 0–0.55 mg/L, which is slightly higher than other laboratory (0.25 mg/L [6] (link)). The detection limit was 0.05 mg/L, and the dynamic range was from 0.07 to 35.2 mg/L. The intra-assay coefficient of variation [CV] and inter-assay CV were 1.5–3.4%, 2.6%–4.5%, respectively. Plasma levels of glucose, C-reactive protein (CRP), leucocyte count, prothrombin time (PT), activated partial thromboplastin time (APTT), thrombin time (TT) and fibrinogen (FBG) were also tested by standard method. For all measurements, levels that were not detectable were considered to have a value equal to the lower limit of detection of the assay.