Value of Procalcitonin and C-Reactive Protein as Early Markers of Bacteraemia Among Patients With Haematological Malignancies Receiving Chemotherapy,Lusaka,Zambia

Abstract

Introduction: The immune system of patients with haematological malignancies is suppressed during chemotherapy. This renders them vulnerable to frequent infections especially bacterial. 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 to come up with laboratory markers that can detect an infectious process at an early stage. Aim: The aim of this study was to determine the value of using Procalcitonin (PCT) and C reactive protein (CRP), for early diagnosis of infection in patients with haematological malignancies receiving chemotherapy. Method: 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 presentation were collected after obtaining informed consent. Then Specimens were collected for measurement of PCT, CRP and for bacteriological analysis. Patients were divided into two groups; those with a bacterial culture positive and negative result. Procalcitonin and CRP concentrations were compared between groups using t-test and non-parametric statistical tests respectively. The area under ROC curve, sensitivity, specificity, likelihood ratio, and Spearman's correlation coefficient also calculated. Results: A total 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 5.1ng/mL is diagnostic for infections (sensitivity 71%, specificity 65%) 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: Procalcitonin measurements can be of value in the early diagnosis of bacteraemia in patients with haematological malignancies. In contrast, the diagnostic sensitivity and specificity VIII for CRP was found to be too low in this study to safely rely on it as a marker of bacteraemia in patients with haematological malignancies. Key words: Procalcitonin (PCT), C reactive protein (CRP), Haematological Malignancies, Bacteraemia Marker