|
Though several of the genes causing HPS have been identified there are still thought to be several that have not been found. For this reason, it is premature to genetically test for HPS. The standard for the differential diagnosis remains testing for the platelet defect. Standard blood tests [i.e., prothrombin time (PT), partial thromboplastin time (PTT), platelet count, and a bleeding time] DO NOT identify the platelet defect in HPS. Those tests count the platelets and there are a normal if not higher amout of platelets present. The problem is that they are not produced correctly in the bone marrow so they do not work properly. It is qualitative not quantitative. For proper diagnosis the platelets must be examined under an electron microscope to observe the absence of dense bodies (the chocolate chips). Special laboratories are needed for this test. Contact the HPS Network if more information or assistance is needed. |