To diagnose dengue, documenting the timing of clinical manifestations is as important as documenting their occurrence. These data are from a group of 57 patients diagnosed with DHF in Puerto Rico in 1990 and 1991, and are consistent with findings in case series from Southeast Asia. From this group, we can determine, on average, when these manifestations occur with respect to time zero, which is the onset of symptoms.

• On average, admission occurred at 4.5 days.
• Thrombocytopenia was usually the earliest predictor of severe disease, often occurring before fever abated.
• Peak hemoconcentration, the highest hematocrit, occurred between day 5 and 6. With IV fluid administration, the hematocrit returned to normal between days 7 and 8, on average.
• Within 24 hours of peak hemoconcentration, the lowest diastolic blood pressure and lowest platelet count occurred.
• Hospital discharge generally occurred at about day 11 after symptom onset—so the patients stayed in the hospital about one week.