Report on the 19th International Society of Blood Transfusion Platelet Immunology Workshop 2018.

BACKGROUND AND OBJECTIVES: The aims of the 19th International Society of Blood Transfusion Platelet Immunology Workshop were to compare the sensitivity and specificity of in-house and commercially available methods for the detection of alloantibodies against human platelet antigens. Survey regarding laboratory management of samples collected for the diagnosis of foetal neonatal alloimmune thrombocytopenia was also conducted. MATERIALS AND METHODS: Twenty-nine laboratories from 17 countries were invited to participate. Seven serum or plasma samples for antibody identification and eight DNA samples for genotyping were sent to participating laboratories. Additionally, samples, critical reagents, materials and instructions for three exercises, one using a commercial kit (Pak Lx), one on platelet preparation for the detection of anti-HPA-3 antibodies and one for testing four anti-CD109 monoclonal antibodies for anti-HPA-15 antibody detection, were provided. RESULTS: Anti-HPA-1a, anti-HPA-2b, anti-HPA-5b and anti-GPIV were detected by the majority of the 28 reporting laboratories using their respective in-house MAIPA assay and/or a commercially available assay. Conversely, very few laboratories correctly identified anti-HPA-3a and HPA-15b. DNA genotyping of HPA and HLA alleles was highly accurate, with just a few discrepancies relative to the expected results. The Pak Lx kit has proven reliable for detecting anti-HPA-1a, anti-HPA-5a and anti-HLA; however, it failed at identifying an anti-HPA-3a in a clinical sample. CONCLUSIONS: Some anti-platelet alloantibodies are reliably and consistently detected, yet others remain difficult to detect. Genotyping of HPA and HLA alleles has proven to be highly accurate and robust. Future work should focus on optimizing the detection of anti-HPA-3 and anti-HPA-15 antibodies.

Systematic reviews of scores and predictors to trigger activation of massive transfusion protocols.

BACKGROUND: The use of massive transfusion protocols (MTPs) in the resuscitation of hemorrhaging trauma patients ensures rapid delivery of blood products to improve outcomes, where the decision to trigger MTPs early is important. Scores and tools to predict the need for MTP activation have been developed for use to aid with clinical judgment. We performed a systematic review to assess (1) the scores and tools available to predict MTP in trauma patients, (2) their clinical value and diagnostic accuracies, and (3) additional predictors of MTP. METHODS: MEDLINE, EMBASE, and CENTRAL were searched from inception to June 2017. All studies that utilized scores or predictors of MTP activation in adult (age, ≥18 years) trauma patients were included. Data collection for scores and tools included reported sensitivities and specificities and accuracy as defined by the area under the curve of the receiver operating characteristic. RESULTS: Forty-five articles were eligible for analysis, with 11 validated and four unvalidated scores and tools assessed. Of four scores using clinical assessment, laboratory values, and ultrasound assessment the modified Traumatic Bleeding Severity Score had the best performance. Of those scores, the Trauma Associated Severe Hemorrhage score is most well validated and has higher area under the curve of the receiver operating characteristic than the Assessment of Blood Consumption and Prince of Wales scores. Without laboratory results, the Assessment of Blood Consumption score balances accuracy with ease of use. Without ultrasound use, the Vandromme and Schreiber scores have the highest accuracy and sensitivity respectively. The Shock Index uses clinical assessment only with fair performance. Other clinical variables, laboratory values, and use of point-of-care testing results were identified predictors of MTP activation. CONCLUSION: The use of scores or tools to predict MTP need to be individualized to hospital resources and skill set to aid clinical judgment. Future studies for triggering nontrauma MTP activations are needed. LEVEL OF EVIDENCE: Systematic review, level III.