Is Total Serum Nitrite and Nitrate (NOx) Level in Dengue Patients a Potential Prognostic Marker of Dengue Hemorrhagic Fever?

Potential use of total nitrite plus nitrate (NOx) and nitrite (NO(2) (−)) separately as surrogate markers for serum nitric oxide in severe dengue and their longitudinal changes along with the progression of infection was studied. Deproteinized sera from confirmed dengue fever (DF, n = 145) and dengue hemorrhagic fever (DHF, n = 74) patients on admission—A, critical—C, discharge—D, and convalescence—CON stages and from age-gender matched healthy individuals (HC, n = 77) were taken to assess NO(2) (−) and NOx levels using Griess and modified Griess assays. Serum NOx in DHFA was significantly lower compared to DFA (p < 0.001). HC had the lowest NOx and NO(2) (−) compared to all patient categories (p < 0.001) except NO(2) (−) in DF-CON and DHF-CON and NOx in DHF-CON. Serum NOx and NO(2) (−) in DHF patients admitted on fever day 3 (DHFA-3) was significantly lower compared to DFA-3 (p < 0.05). Cut-off values of 4.46 μM for NOx (91.3% sensitivity and 80.1% specificity) and 1.25 μM for NO(2) (−) (75.0% sensitivity and 73.3% specificity) were obtained for day 3 of fever. Serum NOx may be used as potential prognostic marker of DHF in patients presenting with DF in the early stage (on day 3 of fever) of the disease.