Abstract
The Platelet Function Analyzer (PFA)$^{(R)}$-100 measures the ability of platelets activated in a high-shear environment to occlude an aperture in a membrane treated with collagen and epinephrine (CEPI) or collagen and ADP (CADP). The time taken for the flow across the membrane to stop (closure time, CT) is recorded. The aim of this study was to assess the potential of the PFA$^{(R)}$-100 as a primary clinical screening tool using the wide spectrum of clinical samples assessed for platelet function as well as to perform the optimal algorithm for the use of PFA$^{(R)}$-100. We established the reference interval in 460 hospital inpatients defined as having normal platelet function based on classical laboratory tests. The reference interval by using the range $5^{th}$ and $95^{th}$ percentile was 84~251 seconds for males CEPI-CT and 85~249 seconds for females CEPI-CT. A total of 1,200 inpatients were enrolled to identify impaired hemostasis before surgical interventions. The abnormal group showing prolonged CEPI-CT was 303 cases (18.9%). Only 3 cases had both abnormal CEPI-CT and CADP-CT. Several factors including sample errors, drugs, hematologic abnoralities were contributed to unexpected prolonged CEPI-CT for screening test. The von Willebrand factor (vWF:Ag) assay was performed only in one patient to verify the algorithm for the use of PFA$^{(R)}$-100. The PFA$^{(R)}$-100 was sensitive and rapid method for primary screening test of platelet dysfunction, so we can substitute it for the bleeding time in routine clinical practice.