Differential Cell Count and CRP Level in Blood as Predictors for Middle East Respiratory Syndrome Coronavirus Infection in Acute Febrile Patients during Nosocomial Outbreak

Park, Ga Eun; Kang, Cheol-In; Ko, Jae-Hoon; Cho, Sun Young; Ha, Young Eun; Kim, Yae-Jean; Peck, Kyong Ran; Song, Jae-Hoon; Chung, Doo Ryeon

We performed a case-control study to identify potential clinical predictors and evaluate differences of initial laboratory data including complete blood counts (CBC) with differential count as predictors for MERS-CoV infection. The cases were defined as hospitalized patients with laboratory-confirmed MERS-CoV infection in the Samsung Medical Center (SMC), a 1,950-bed university-affiliated tertiary care center, between May 2015 and July 2015. The controls were selected from the pool of patients, mostly healthcare workers, who were admitted to the SMC with acute febrile illness (body temperature > 38°C) suspected of viral infection during the same period of the outbreak. The confirmatory diagnostic testing for patients suspected to have MERS-CoV infection was performed as reported previously (8) , and the controls were classified when the MERS-CoV test was negative. Patients were excluded if they did not have epidemiologic links with the nosocomial outbreak in the SMC, or if initial blood tests were not done in the SMC. Patients who were transferred from other hospitals and those who had serious underlying diseases such as solid cancer, hematologic malignancy, life-threatening uncontrolled infections, congestive heart failure or acute myocardial infarction were also excluded in the study population ( Fig. 1) . We obtained the following data for each patient from electronic medical records; age, gender, clinical symptoms, underlying diseases, and initial laboratory findings including CBC with differential count, total bilirubin, alanine aminotrans- Of 45 patients with MERS-CoV infection who were admitted to the SMC, a total of 30 cases were included in the study, and compared with 43 controls whose MERS-CoV test was negative. Demographic data and baseline characteristics of the study population are presented and compared between the case and control groups in Table 1 . The mean ages of the case and control patients were 43.8 and 32.5 years, respectively. The proportion of male patients in the case group was higher than in the control group (60.0% vs. 28.3%; P = 0.006). There were no significant differences in the underlying diseases except cardiovascular diseases (13.3% vs. 0%; P = 0.025) and hypertension (16.7% vs. 0%; P = 0.009). At the time of hospital admission, newly developed cough, sputum, and dyspnea were more frequently seen among the cases than the controls (36.7% vs. 11.6%; P = 0.011), whereas diarrhea were more frequently seen among the control group (2.0% vs. 55.8%; P < 0.001). 164 ; P = 0.021). In contrast, leukocytosis (0% vs. 48.8%; OR, 0.512; 95% CI, 0.382-0.685; P < 0.001) with relative lymphopenia (30% vs. 100%; OR, 0.300; 95% CI, 0.174-0.518; P < 0.001) were more frequently seen in the control group. In addition, CRP level lower than 0.5 mg/dL was more seen in the case group than in the control group (36.7% vs. 4.7%; OR, 11.868; 95% CI, 2.392-58.892; P < 0.001) and median CRP level was significantly lower in the case group than in the control group (0.76 vs. 1.82 mg/dL; P < 0.001). Lymphocytosis was not seen in both groups and there were no significant differences in hemoglobin level and platelet counts. All patients in the control groups recovered spontaneously without antimicrobial treatment.