I have been seeing more patients referred for low platelet counts, especially during dengue epidemics. Here are two cases.
Case 1: Ms. J, eight months pregnant
Ms. J was referred because her platelet count was reported as 20,000. I found that her platelets were reacting to the EDTA chemical in the blood collection tube and clumping together. The cell-counting machine reported this as a low count. When her blood was checked without EDTA, her platelet count was 2,00,000, completely normal.
Case 2: Baby D, six years old, with dengue
Baby D's platelets were reported as 18,000. It was the same phenomenon: the actual platelet count without EDTA was 2,30,000.
The bottom line
This is known as pseudothrombocytopenia: there is actually nothing wrong with the patient or their blood. A surprisingly low platelet count, especially without any bleeding, should be checked with a fresh sample and a microscope before any treatment is given.