The value of procalcitonin and C-reactive protein as early markers of bacteraemia among patients with haematological malignancies receiving chemotherapy: a cross-sectional study

Abstract

Background: The immune system of patients with haematological malignancies is suppressed during chemotherapy. This renders them vulnerable to frequent infections especially of the bacterial type. Timely diagnosis of these infections is difficult, because a severe infection may be asymptomatic or manifest only in the form of fever or malaise. There is need for laboratory markers that can detect an infectious process at an early stage. This study was aimed at determining the value of using Procalcitonin (PCT) and C reactive protein (CRP), for early diagnosis of infection in patients with haematological malignancies receiving chemotherapy.

Methods: This was a cross sectional study consisting of sixty eight (68) patients with haematological malignancies. Data from each participant including sex, age, clinical and laboratory data were collected after obtaining informed consent. Blood specimens were then collected for measurement of PCT, CRP and bacteriological analysis. Patients were divided into two groups; those with a culture positive and negative result. PCT and CRP concentrations were compared between groups using t-test and nonparametric statistical tests respectively. The area under ROC curve, sensitivity, specificity, likelihood ratio, and Spearman's correlation coefficient were also calculated.

Results: Atotal of 14 (20.6%) microorganisms were isolated, of which 10 were gram-positive bacteria and 4 were gram-negative bacilli. The mean values of PCT which were 6.1ng/mL in the bacteraemia group and 5.1ng/mL in the non-bacteraemia group, p=0.023 and median CRP values were 24.2 (6.43- 48.15) in the bacteraemia and 23.5 (6.03-75.44) in the non-bacteraemia group, p=0.832. The area under curves was 0.52 (95% CI=0.57-0.84) for CRP and 0.70 (95% CI=0.35-0.69) for PCT. PCT value of greater than 4.7 ng/mL is diagnostic for infections (sensitivity 86%, specificity 54%) while that of CRP was 21mg/mL with the sensitivity and specificity of 64% and 44% respectively. Elevated levels of PCT as well as fever were significantly associated with bacteraemia.

Conclusion: PCT was a more reliable and sensitive marker of bacteraemia among patients with  haematological malignancies receiving chemotherapy than CRP.

Keywords: Procalcitonin (PCT), C reactive protein (CRP), Haematological Malignancies, Bacteraemia Marker