Dengue is the the most common mosquito borne arboviral disease in tropical regions of the world. Common hematological abnormalities seen with
dengue fever are leukopenia followed by thrombocytopenia. Coagulopathy may also be seen in dengue fever. This study aims to observe the trends
of PT and aPTT prole in dengue fever. Materials and methods: This was an observational study done at Narayana medical college and hospital,
Nellore, from June 2021 to October 2022 on 180 dengue patients satisfying inclusion and exclusion criteria. Prothrombin time (PT) and activated
partial thromboplastin time (aPTT) values of all the study patients were noted. Laboratory control value for PT was 13.1sec, aPTT control value
was 34sec. Values above these were considered abnormal. PTand aPTTvalues of all the 180 patients included in the study were noted at admission
and median values were calculated. Results: Out of 180 dengue patients studied, 95.6% of the patients had normal PTand 78.8% of the patients had
prolonged aPTT . Median value of PT observed in this study was 13.8 sec, median value of aPTT observed in this study was 48.9sec. Conclusion:
Isolated aPTT prolongation with a normal PT is seen in dengue fever as commonly as thrombocytopenia. Moreover, in addition to
thrombocytopenia, coagulopathy as represented by prolongation of aPTT is an important contributor of bleeding risk to be noted in patients with
dengue fever.