Diagnostic Management Team: Platelet Refractory Algorithm and Consult

Abstract

Abstract Platelet refractoriness occurs when a patient fails to achieve appropriate platelet count increment following platelet (plt) transfusion. Approximately 30% to 40% of cases are due to human leukocyte antigen (HLA) alloantibodies and 2% to 10% are due to human platelet antigen (HPA) alloantibodies, which can be detected by various assays. The results of these tests are then used to guide selection of appropriate units, such as crossmatch-compatible (XM) and HLA-matched (HLAm) plts. Given the various steps and tests involved in diagnosing and managing plt refractoriness, clinicians may order unnecessary tests resulting in delays in patient care. In April 2018, our institution formed a diagnostic management team (DMT) to establish an algorithmic approach to testing, diagnosing, and transfusing plt refractory patients. We performed a retrospective review of clinician requests for XM or HLAm plts over a 9-month period prior to the launch of the DMT and compared that to requests placed during the initial 9-month period following the launch of the DMT. We collected the date transfusion medicine (TM) service was notified and the time to complete the following: 1-hour corrected count increment (CCI), ELISA indirect antibody screen, HLA flow cytometry PRA screen, HLA single antigen bead (SAB), and obtain the first XM or HLAm plt unit for the patient. There were 12 and 20 patients evaluated for plt refractoriness pre- and post-DMT, respectively. The median time to complete the ELISA indirect antibody screen was 2 days pre- and post-DMT, respectively. Eight percent of patients never had an ELISA screen performed pre-DMT. All patients meeting plt refractory criteria had ELISA screens performed post-DMT. Median time to complete HLA testing decreased from 4 days to 2 days and all patients who had positive FlowPRAs had subsequent SABs performed post-DMT compared to only 40% of patients pre-DMT. The median times to obtain the first XM unit were 6 and 5 days and the first HLAm unit was 5 and 6 days pre- and post-DMT, respectively. One patient had a CCI above 7,500 and four patients had negative screening ELISA and FlowPRA tests after the launch of the DMT. No further testing was performed and they continued to receive ABO-compatible (ABOc) plt units. Since the launch of the DMT, there is improved consistency regarding what tests are performed and standardization of the sequence in which the appropriate tests are ordered. We have reduced unnecessary testing by identifying patients with nonimmune-mediated etiologies of plt refractoriness. Divergence from the algorithm is the main issue encountered during the initial 9-month period following implementation of the DMT. This divergence stemmed from lack of consistent education about plt refractoriness and the DMT. We believe better adherence to the algorithm will lead to decreased product acquisition time and further improve efficiency.