Purpose: To determine the change of red blood cell, white blood cell counts and serum procalciton level in patients with primary lung cancerat time of diagnosis. Methods: A descriptive, cross - sectional study was conducted at time of diagnosis of 140 lung cancer patients versus 40 pneumonia patients at Oncology Department, 71 Central Hospital, from 7/2017 to 10/2020. Red blood cell (RBC), white blood cell counts (WBC), and serum procalcitonin (PCT) level were evaluated. Result: The mean value of hemoglobin in the lung cancer group was lower than that in the pneumonia group, which was 92.90 ± 27.10g/L compared with 117.78 ± 35.08g/L (p <
0.01). The mean of hemoglobin in the small - cell lung cancer group was lower than that in the non - small - cell lung cancer group, which was 57.77 ± 4.57g/L and 96.50 ± 25.84g/L, respectively (p <
0.01). The WBC in the lung cancer group was 12.07 ± 4.53G/L, higher than in the pneumonia group of 8.52 ± 4.16G/L (p <
0.01). The histopathological group had an average WBC of 15.23 ± 1.42G/L in the non - small - cell lung cancer group, compared to 11.74 ± 4.62G/L in the small - cell lung cancer group (p <
0.01). Stage IV non - small - cell lung cancer and extensive - stage small cell lung cancer had the highest WBC of 15.44 ± 1.99 and 15.56 ± 1.42G/L. PCT within 0.05 and 2ng/ml in the lung cancer group and the pneumonia group was 0.81 ± 0.97ng/ml and 0.88 ± 0.84ng/ml, respectively
but PCT >
10ng/ml in the pneumonia group was higher than that in the lung cancer group, which was 13.13 ± 2.49ng/ml and 12.05 ± 1.64ng/ml. PCT in 3 levels between the lung cancer group and the pneumonia group did not differ. Conclusion: This study showed a difference in hemoglobin in the lung cancer group was lower than the pneumonia group. The WBC in the lung cancer group was higher than the pneumonia group. The rate of anemia was more common in the group of patients with advanced cancer. PCT >
10ng/ml concentration of the pneumonia group was higher than the lung cancer group.