Study on changes in a subset of full blood count parameters of patients with dengue fever and dengue haemorrhagic fever presented to teaching hospital - Kurunegala, Sri Lanka - a descriptive cross-sectional study.

Background: Dengue is a viral infection with a notable surge in prevalence over the past few decades making it a global problem. Haematological and biochemical parameters keep changing throughout the disease process. This research studied the patterns of a subset of full blood count parameters of patients with dengue fever during different phases of the illness.

Methods: A descriptive cross-sectional study was conducted at the Teaching Hospital - Kurunegala (THK) from April-2021 to March-2022. Patients diagnosed with dengue fever were recruited on all-inclusive, nonselective basis. Demographic data were collected using an interviewer-administered questionnaire and investigation results were obtained from clinical records. Ethical approval was obtained from the Ethics Review Committees of the Faculty of Medicine, University of Kelaniya and THK.

Results: A total of 137 patients were recruited, of which 27 went into the critical phase. Patients were admitted within two to six days of the onset of fever, and 44.5% were admitted on the day five. Although the mean white blood cells count of the leakers (7.12 ± 3.21) was significantly higher (p = < .001) when compared to the non-leakers (5.26 ± 2.23) during the convalescent phase, it was not significant in the febrile phase. The mean haematocrit value of the leakers was higher (43.01 ± 4.66) in the febrile phase, whilst the haematocrit value of the non-leakers was higher (42.30 ± 36.17) in the convalescent phase. The difference in means of haematocrit values was statistically significant only in leakers (p = .007) in the febrile phase when compared to the non-leakers.

Conclusion: Nearly half of the patients were admitted on day five, which increases the risk of not being able to identify the critical phase early, which may have a significant impact on the outcome. The results confirm the value of dropping platelet count and rising haematocrit value as the markers of leaking. Higher white blood cell count observed in both leakers and non-leakers during the convalescence phase indicates that it can be used as a predictive factor of identifying the patient entering the convalescent phase.