Citations

The presence of increased multinucleated megakaryocytes (aka osteoclast-like) is considered a dysplastic feature in myelodysplastic syndrome; however, its clinical significance in isolation is uncertain. Herein, we report the clinicopathologic and genetic features of 18 such cases of 40,539 bone marrow biopsies spanning 10 years. All 18 patients had ≥25% multinucleated megakaryocytes in otherwise normal bone marrow biopsies, which were evaluated for plasma cell neoplasms (n=9), lymphoma (n=4), or anemia/neutropenia (n=5). None of the 17 patients tested showed acquired cytogenetic abnormalities. Sixteen patients underwent targeted gene panel next-generation sequencing: 9 patients had no pathogenic mutations; 3 harbored a single pathogenic mutation with variant allele frequencies of 7.5%, 7.6%, and 10.7%, likely representing clonal hematopoiesis of indeterminate potential; 1 had 2 pathogenic mutations, 1 of which had a variant allele frequency >20%. Fourteen of 18 patients had a follow-up period >6 months (median: 36.5 mo, range: 7 to 110 mo) and no patients developed a new-onset cytopenia, a progressive cytopenia, or a myeloid neoplasm. The patient with 2 mutations had persistent anemia, worrisome for an emerging MDS. However, given the absence of thrombocytopenia, increased multinucleated megakaryocytes in this patient could be an unrelated incidental finding. Our study indicates that increased multinucleated megakaryocytes as an isolated finding is a rare phenomenon, and this sole morphologic finding is not diagnostic of myelodysplastic syndrome. Diagnostic approaches in the presence of increased multinucleated megakaryocytes are proposed based on different clinical and pathologic scenarios.

Abstract Patients with core-binding factor (CBF) acute myeloid leukemia (AML), caused by either t(8;21)(q22;q22) or inv(16)(p13q22)/t(16;16)(p13;q22), have higher complete remission rates and longer survival than patients with other subtypes of AML. However, ∼40% of patients relapse, and the literature suggests that patients with inv(16) fare differently from those with t(8;21). We retrospectively analyzed 537 patients with CBF-AML, focusing on additional cytogenetic aberrations to examine their impact on clinical outcomes. Trisomies of chromosomes 8, 21, or 22 were significantly more common in patients with inv(16)/t(16;16): 16% vs 7%, 6% vs 0%, and 17% vs 0%, respectively. In contrast, del(9q) and loss of a sex chromosome were more frequent in patients with t(8;21): 15% vs 0.4% for del(9q), 37% vs 0% for loss of X in females, and 44% vs 5% for loss of Y in males. Hyperdiploidy was more frequent in patients with inv(16) (25% vs 9%, whereas hypodiploidy was more frequent in patients with t(8;21) (37% vs 3%. In multivariable analyses (adjusted for age, white blood counts at diagnosis, and KIT mutation status), trisomy 8 was associated with improved overall survival (OS) in inv(16), whereas the presence of other chromosomal abnormalities (not trisomy 8) was associated with decreased OS. In patients with t(8;21), hypodiploidy was associated with improved disease-free survival; hyperdiploidy and del(9q) were associated with improved OS. KIT mutation (either positive or not tested, compared with negative) conferred poor prognoses in univariate analysis only in patients with t(8;21).

Background Eculizumab, a monoclonal antibody targeting C5, is an effective treatment for complement-mediated thrombotic microangiopathy (CM-TMA), also known as atypical hemolytic uremic syndrome. Although lifelong therapy has been suggested, the optimal treatment schedule is unknown, while eculizumab discontinuation does not universally lead to relapse. Data evaluating risk factors associated with an increased risk of CM-TMA recurrence following eculizumab withdrawal are scarce. Prior to the eculizumab era, complement genetic studies have been used to assess morbidity and mortality in patients with CM-TMA. Our aim was to assess the impact of complement gene variants on CM-TMA relapse rate (RR) after eculizumab discontinuation. Methods Search protocols were developed for the Ovid and PubMed databases to identify existing reports on CM-TMA and eculizumab withdrawal published before February 1st 2020. Cases were cross-referenced to eliminate duplicates. Inclusion criteria included patients diagnosed with CM-TMA who had undergone eculizumab discontinuation. Reasons for exclusion were patients with no follow-up after eculizumab withdrawal and patients lacking complement gene testing. Patients undergoing eculizumab dose extension, but not discontinuation, were not included. Results Fifteen studies including 557 individuals were retrieved. Of these, 363 (65.2%) were excluded as outlined in Figure 1 and 194 cases were included in the final analysis with a global RR of 28.9% (n=56). Distribution based on gene impacted and variant type are presented in Table 1. RR was highest among patients with CFH variants (52.5% to 60%) -particularly if involving exon 22 or nonsense mutations-, MCP/CD46 variants (38.9% to 45%) -particularly if affecting splice regions-, and cases with multiple concomitant variants (57.1%) -particularly those including CFH or a CFH-CFHR1 Hybrid (Table 2). Patients with relapse were more likely to have the presence of a complement variant (p<0.001), history of previously resolved CM-TMA events (p=0.022), younger age (mean age 22.4 years for patients with relapse vs. 32.33 years for patients without relapse; p=0.002) and, within those with detected variants, multiple vs. single variants (p=0.002) and CFH-inclusive variants (p=0.003). On univariate analysis, complement gene variants (OR 4.217 95%CI 1.97-9.026; p<0.001), age <30 years (OR 2.346 95%CI 1.159-4.749; p=0.018), and presence of multiple variants (OR 2.06 95%CI 1.172-3.621; p=0.012) or CFH-inclusive variants (OR 3.111 95%CI 1.443-6.71; p=0.004) were associated with increased odds of CM-TMA relapse, while no prior history of additional CM-TMA events was the only factor associated with lower RR (OR 0.327 95%CI 0.123-0.87; p=0.025). Presence of complement variants (OR 4.48 95%CI 1.132-17.724; p=0.033) and CFH-inclusive variants (OR 3.045 95%CI 1.136-8.159; p=0.027) were independently associated with increased RR on multivariate analysis (Table 3). Conclusion Relapse after eculizumab discontinuation is rare in cases with no genetic variants identified but can increase to more than 80% in high-risk subgroups. Complement genetic testing is not required for CM-TMA diagnosis or for initiation of complement inhibiting therapy; however, our results demonstrate the value of complement genetic testing when stratifying risk of patients for consideration of eculizumab discontinuation. Disclosures Sridharan: Alexion: Honoraria.

Abstract Objectives SF3B1 mutations are the most common mutations in myelodysplastic syndromes (MDS). The International Working Group for the Prognosis of MDS (IWG-PM) recently proposed SF3B1-mutant MDS (SF3B1-mut-MDS) as a distinct disease subtype. We evaluated the spectrum and molecular landscape of SF3B1-mutated myeloid disorders and assessed the prognostication in MDS harboring SF3B1 mutations (MDS-SF3B1). Methods Cases were selected by retrospective review. Clinical course and laboratory and clinical findings were collected by chart review. SF3B1-mut-MDS was classified following IWG-PM criteria. Results SF3B1 mutations were identified in 75 of 955 patients, encompassing a full spectrum of myeloid disorders. In MDS-SF3B1, Revised International Prognostic Scoring System (IPSS-R) score greater than 3 and transcription factor (TF) comutations were adverse prognostic markers by both univariate and multivariate analyses. We confirmed the favorable outcome of IWG-PM-defined SF3B1-mut-MDS. Interestingly, it did not show sharp prognostic differentiation within MDS-SF3B1. Conclusions SF3B1 mutations occur in the full spectrum of myeloid disorders. We independently validated the favorable prognostication of IWG-PM-defined SF3B1-mut-MDS. However it may not provide sharp prognostication within MDS-SF3B1 where IPSS-R and TF comutations were prognostic-informative. Larger cohort studies are warranted to verify these findings and refine MDS-SF3B1 prognostication.

AbstractIntroductionHemolysis, icterus, and lipemia (HIL) are common pre‐analytical variables in the clinical laboratory. Understanding their effects on coagulation laboratory results is essential.MethodsHIL effects on the prothrombin time (PT), activated partial thromboplastin time (APTT), dilute Russell's viper venom time (DRVVT), thrombin time (TT), and protein C chromogenic activity (CFx) were evaluated on the ACL TOP 750 optical analyzer and STA‐R Evolution mechanical analyzer (PT and APTT only) by spiking normal donor, patient, and commercial control samples with varying concentrations of hemolysate, bilirubin, or a lipid emulsion. The relative difference or bias compared to the original results was determined.ResultsHemolysis (H) indices up to 900 mg/dL did not affect the APTT, PT, DRVVT Confirm, TT, and CFx; however, H indices above approximately 200 mg/dL resulted in a false‐negative DRVVT screen and screen/confirm ratio in samples with a lupus anticoagulant. There was an artifactual prolongation of the PT and APTT when conjugated bilirubin was dissolved in aqueous solvents and not when it was dissolved in dimethyl sulfoxide. Icterus (I) indices up to 45 mg/dL did not result in significant (>15%) bias for all assays evaluated. The PT and APTT assays failed to produce a robust clot curve when the lipemia (L) index exceeded 6000 milliabsorbance units (mAbs), and the TT and DRVVT assays failed when the L index exceeded 3000 mAbs; the CFx assay was unaffected by lipemia.ConclusionsVerification of the manufacturer's recommended interference thresholds is important since it may avoid inappropriate instrument flagging and/ or sample rejection.

INTRODUCTION: Autoantibody effects of monoclonal proteins have been described in multiple organ systems. We previously found a 5-fold higher prevalence than expected of monoclonal gammopathy (MG) in adults with TMA (21% versus 4.2%; Ravindran A et al, Kidney Int 2017). Here we investigated the prevalence of MG in patients undergoing evaluation for TMA with an ADAMTS13 (a disintegrin and metalloprotease with a thrombospondin type 1 motif, member 13) activity assay performed as part of routine clinical care to evaluate for a signal of possible autoantibody pathophysiology in patients with immune thrombotic thrombocytopenic purpura (iTTP). METHODS: WAfter IRB approval, waste plasma samples from patients who had ADAMTS13 activity and inhibitor assay (Lifecodes, ATS-13, Immucor) were archived. Eligible patients included those with the following: i) ADAMTS13 activity level < 30% (n=26), ii) ADAMTS13 activity level >30% but with prior documentation of a value < 30% (n=4). A control cohort (n=49) of patients with ADAMTS13 activity level >30% (and no prior samples with a level < 30% recorded) was also included. Matrix-assisted laser desorption/ionization-time of flight mass spectrometry detection (MALDI-TOF) was used for MG assessment. Mass spectrometry findings of only an IgG kappa MG appearing consistent with rituximab were reviewed and considered negative for MG if the patients had received rituximab prior to sample collection. Medical records were retrospectively reviewed and the following patients were excluded: i) <18 years of age (n=4), ii) iTTP in remission (n=4) at the time of sample collection, and iii) absence of microangiopathy (n=11). RESULTS: Sixty patients met eligibility criteria with the following final diagnoses: iTTP (n=14), transplant-associated TMA (n=12), infection (n=11), malignancy (n=6), complement-mediated TMA (n=5), drug-induced TMA (DITMA; n=5), shock liver (n=2), pancreatitis (n=1), cryoglobulinemia (n=1), and multifactorial (n=3). The median age was 56.5 years (yr) (standard deviation 14.4, range18-81) and 58% of patients were female. The median age was similar among patients with (57 yr) and those without MG (56 yr). Median ADAMTS-13 activity of the whole study population was 52% (0-100%); 6/14 patients with an inhibitor screen performed on the same sample had a positive result; median titer was 1.2 Bethesda units (range <0.4 - 2.8). Treatments of the acute presentation included corticosteroids (n=32), plasma exchange (n=21), rituximab (n=9), and eculizumab (n=4). None of these patients received a multiple myeloma-type treatment regimen as part of their acute management. A MG was identified in 25 patients: monoclonal in 14 patients, biclonal in 10 patients, and triclonal in 1 pt. Among the 14 patients with a single monoclonal protein, the distribution of heavy and light chains was as follows: IgG (9; 64%), IgM (3; 21%), IgA (2; 14%), lambda (8; 57%), kappa (6; 43%). Receipt of immune-modifying treatment at the time of sample draw was identified in 24 patients (9/25 with a monoclonal protein, 15/35 without a monoclonal protein; not statistically significant by 2-tail Fisher's exact test [p=0.79]), including cancer-directed therapy (n=9), graft-versus-host disease prophylaxis (n=8), solid organ transplant anti-rejection therapy (n=5), and autoimmune disease treatment (n=2). Overall, the proportion of patients with monoclonal gammopathy was similar between iTTP and other diagnoses, detailed in Table 1. Among the 14 pt with iTTP, 4 had a monoclonal protein (IgG kappa [n=2], IgA lambda [n=2]). Additionally, 1 pt with iTTP had biclonal proteins (IgG kappa and IgA kappa), which was consistent with a known prior history of monoclonal gammopathy of undetermined significance. A monoclonal protein was present in 2 of the 6 pt with a detectable inhibitor titer (0.6 and <0.4 Bethesda units). CONCLUSIONS: Patients undergoing evaluation for iTTP with ADAMTS-13 activity testing had a high prevalence of monoclonal proteins across variable underlying diagnoses. In this heterogeneous cohort there was no significant association between iTTP and the presence of MG to support an autoantibody pathophysiologic role. Disclosures Murray: The Binding Site: Patents & Royalties: Patent Use of Mass Spec to identify monoclonal proteins licensed to The Binding Site. Pruthi:HEMA Biologics: Honoraria; Instrumentation Laboratory: Honoraria; Merck: Honoraria; CSL Behring: Honoraria; Genentech Inc.: Honoraria; Bayer Healthcare: Honoraria.

Introduction: The 2013 ASH Choosing Wisely campaign recommends against thrombophilia testing in patients with major transient risk factors for venous thromboembolism (VTE). Our Special Coagulation Laboratory (SCL) offers an algorithmic approach to thrombophilia testing which includes assays for lupus anticoagulant, dysfibrinogenemia, anticoagulant proteins (protein C, protein S, antithrombin), activated protein C resistance with reflex to factor v Leiden (if indicated), and prothrombin G20210A mutation. Samples are received through Mayo Clinic Laboratories (MCL), national and international reference laboratory (often with limited or no clinical information) and from internal Mayo Clinic practice. We hypothesized that thrombophilia testing would decline in cases where it was recommended against following the publication of testing guidelines. Methods: We audited the external thrombophilia testing samples between2013-2019 and internal samples between 2014-2019 (periods during which they were available). For the internal samples, complete test volumes were only available 2014-2019. Because external clients may either adopt internal testing or contract with a different reference laboratory, many clients may not have been retained over the entire observed period. To better understand the ordering practices of consistent clients, external clients which did not have thrombophilia testing sent to MCL each year of the observed period were excluded. We separated internal ordering practices by hematology and oncology or thrombophilia clinic staff and trainees contrasted with those of other specialties. Results: MCL received 18,529 external thrombophilia testing samples from 322 external healthcare systems during the observed period. From 37 clients, 5,878 (38.2%) samples met inclusion criteria. Annual volume of samples ranged from 890 in 2013 to 861 in 2019 (861-1046). Special coagulation lab processed 11,639 internal thrombophilia tests during the observed periods. There was a consistent small annual increase in testing with 1,398 performed in 2014 and 2,430 in 2019. Of 11651 tests ordered, only 18.6% (2167) were ordered by people most likely to be familiar with ASH choosing wisely campaign. Annual thrombophilia testing ordered by hematology and oncology or thrombophilia clinic staff increased from 307 in 2014 to 387 in 2019 (307-432). However, the ordering practices of these providers as a proportion of overall practices declined from 22.0% (307/1398) in 2014 to 15.9 % (387/2430) in 2019. Table Discussion: Our preliminary data showed no significant trend in thrombophilia ordering practices among included external clients since publication of the ASH Choosing Wisely guidelines on thrombophilia testing. Internally we found a consistent small rise in numbers of thrombophilia tests ordered since 2014 but this may reflect changes in patient volume. We observed that the majority of internal thrombophilia testing was ordered by non-hematology/oncology or thrombophilia providers who are perhaps less likely to be familiar with ASH Choosing Wisely guidelines. The proportion of testing ordered by hematology & oncology or thrombophilia providers declined during the observed period. Our findings are limited by lacking information on the indication and appropriateness for testing as well as possibility of change in patient population. However the overall trend in test volumes and specialty of ordering providers deserves attention and highlight the value in educating other medical societies on ASH Choosing Wisely recommendations for thrombophilia testing. Future work will focus on appropriateness for thrombophilia testing including the indication and time (remote from anticoagulation and acute thrombotic episode), location of testing (inpatient vs. outpatient), as well as investigating if testing has changed patient management, which may help in creating new Choosing Wisely recommendations for thrombophilia testing. Figure 1. Disclosures Pruthi: HEMA Biologics: Honoraria; Bayer Healthcare: Honoraria; Merck: Honoraria; Instrumentation Laboratory: Honoraria; Genentech Inc.: Honoraria; CSL Behring: Honoraria.

Introduction: In patients with SARS-CoV-2 COVID-19 infection elevated D-dimers are associated with a poor prognosis. Although suggestive of DIC, the majority of patients do not fulfil ISTH criteria for DIC. Studies have demonstrated that when compared to D-dimer, fibrin monomers are more sensitive and specific when differentiating overt DIC from non-overt DIC. Our special coagulation laboratory (SCL) routinely measures soluble fibrin monomer complex (SFMC) as part of our DIC profile in samples with elevated D-dimers. Here we aimed to investigate the percentage of patients with COVID-19 infection with elevated SFMC as performed as part of the DIC profile. Methods: Between April 1st 2020 and July 26, 2020 inpatients at the Mayo Clinic Rochester, MN campus with COVID-19 infection who underwent DIC testing in SCL were identified through SCL database. Patients were excluded if SARS-CoV2 PCR results were not available in the Mayo Clinic electronic medical record (EMR). DIC profile components include prothrombin time (PT), activated partial thromboplastin time (APTT), thrombin time (TT), fibrinogen and D-dimer. Reflex SFMC is performed if D-dimer is elevated. Data abstracted from EMR included results of laboratory tests, date of COVID-19 symptom onset, date of SARS-CoV2 PCR positivity, and death within 30 days of hospital admission. The ISTH DIC score was calculated and patients were labeled as overt DIC or non-overt DIC based off of ISTH DIC score ≥5. Results: 35 patients (19 female), median age 59 years (28-91) met our study criteria DIC profiles were obtained 6.5 (1-37) days after COVID-19 symptom onset (n=33) with 28 obtained within 14 days of symptom onset. Time to DIC profile from SARS-CoV2 PCR testing was 4 (0-37) days (n=35) with 31 having testing completed within 14 days of PCR positivity. 8 patients were intubated during hospitalization and of the remaining 27, 67% required supplemental oxygen. 21/35 (60%) patients had an elevated fibrinogen (526.5 mg/dL (201-800)) while 19/35 (54%) had a prolonged PT (12.8 seconds (10.1-99.6) and 5/35 (14%) had a prolonged APTT (31 seconds (24-68)). 17 patients with prolonged PT and 3 patients with prolonged APTT had factor activity assays performed (Figure 1A). 9/35 (25%) had thrombocytopenia (230 x 109/L (12-709) and 27/35 (77%) patients had an elevated D-dimer (895 ng/ml FEU (220- >100,000). D-dimer was higher in males than in females (p: 0.049). Of those with elevated D-dimer only 5/27 (18.5%) had an elevated SFMC (5 mcg/ml (5- >1100) (Figure 1B). 4/35 (11%) patients had ISTH DIC scores ≥ 5 and all had score of 5. All of these patients had D-dimer > 2000 ng/ml while only 2 had elevated SFMC however SFMC in both of these patients was < 15 mcg/ml. Of these, one patient with SFMC of 12 mcg/ml had known cirrhosis and the other with an SFMC of 11 mcg/ml had acute decompensation and associated shock liver. This patient also had venous thrombosis 3 days prior to DIC profile and died from complications related to COVID-19 infection. Of the two other patients with high ISTH score and normal SFMC, one had previous chronic thrombocytopenia of < 50 x109/L while the other had concomitant admission for acute and recurrent pancreatitis in the setting of alcoholism with acute intoxication. Six patients died within 30 days of admission and in 2/5 performed SFMC was elevated (Figure1C). Conclusion: Compared to 77% of patients with elevated D-dimers, of those tested only 18.5 % of patients had elevated SFMC. It has been hypothesized that the elevated D-dimer noted in COVID-19 pulmonary infection is a direct consequence of acute lung injury and not overt DIC. Although preliminary, the small percentage of patients with overt DIC by ISTH criteria and normal SFMC in the majority of the current cohort support this hypothesis; however studies in a larger more controlled cohort are needed to confirm these findings. Disclosures Sridharan: Alexion: Honoraria. Pruthi:Merck: Honoraria; Instrumentation Laboratory: Honoraria; HEMA Biologics: Honoraria; Bayer Healthcare: Honoraria; Genentech Inc.: Honoraria; CSL Behring: Honoraria.

Introduction Germline predisposition syndromes (GPS) are inherited disorders associated with germinal aberrations that increase the risk of malignancies. While aberrations in certain genes increase the risk for all types of malignancies (Tp53, ATM, CDKN2A, CHEK2), there is a growing list of genes associated specifically with hematological malignancies (GATA2, RUNX1, DDX41, ETV6, ANKRD26). At our institution, we have established a hematology GPS clinic to diagnose and manage GPS and with this report, detail our experience with 130 patients. Methods GPS were investigated in pediatric and adult patients with one or more first degree relatives with hematological/visceral malignancies or in those with antecedent thrombocytopenia (ANKRD26, RUNX1, ETV6), or with specific syndromic features (short telomere syndromes/STS, GATA2 haploinsufficiency, Fanconi anemia/FA, Shwachman-Diamond syndrome/SDS). Depending on the phenotype, specific functional assays such as flow-FISH for telomere length assessment and chromosomal breakage assays were ordered. After informed consent and genetic counselling, germline testing was carried out on peripheral blood mononuclear cell, skin fibroblast, or hair follicle-derived DNA. A custom-designed marrow failure NGS panel (200 genes) was used in most cases and interrogation of variants, in silico studies, and functional assays were carried out as previously described (Mangaonkar et al MC Proc 2019). Copy number variations were identified by aCGH. At the time of progression/worsening cytopenias, bone marrow/lymph node biopsies and NGS (next generation sequencing) were carried out where indicated. Results 130 patients with germline predisposition have been identified to date. The spectrum of disorders seen include STS 29 (22%), FA 17 (13%), GATA2 16 (12%), Diamond Blackfan anemia/DBA 13 (10%), RUNX1-FPD 12 (9%), ATM deletions/mutations 11 (8%), ANKRD26 6 (5%), SDS 5 (4%), DDX41 4 (3%), MPL 3 (2%), CHEK2, MECOM, Tp53 mutations 2 (2%) each, and CBL, CEPBA, ELANE, NF1, CDKN2A, CSF3R, ETV6, and GATA1 mutations, 1 (1%) each. Evidence for clonal evolution (CCUS) and hematological malignancies were seen in 51 (39%) patients, involving all the aforementioned genes/syndromes with the exception of DBA, CBL, ETV6, MPL, CSF3R, and GATA1. Seven (64%) of 11 patients with germline ATM deletions/mutations developed lymphoid malignancies; homozygous ATM (Follicular NHL-1, Burkitt lymphoma-1, T-ALL-1, T-LPD-1) and heterozygous ATM (T-PLL-1, DLBCL-1, CLL-1). Clonal evolution occurred in 11 (69%) of 16 GATA2 haploinsufficient patients (CCUS-2, MDS-3, CMML-1, AML-5) and in 7 (58%) of 12 RUNX1-FPD patients (CCUS-1, MDS-1, MDS/MPN-3, AML-2). Five of 29 (17%) STS patients had clonal progression (CCUS-2, MDS-2, AML-1), and 5 (29%) of 17 FA patients progressed to MDS-2 or AML-3. JMML was seen in one patient with a germline NF1 mutation, while 1 (20%) of 5 SDS patients progressed to AML. NGS data at progression was available in 24 (55%) of 44 myeloid/CCUS progressions, with somatic truncating ASXL1 mutations being most frequent (29%), followed by RAS pathway mutations (15%). AML/MDS progressions in STS, FA, and SDS were universally associated with complex/monosomal karyotypes, translating to refractory disease. Seventeen (39%) of 44 patients with myeloid predisposition underwent allogenic HCT (GATA2-7, FA-3, RUNX1-FPD-3, STS-2, NF1-1, Tp53-1), with 10 (59%) being alive at last follow up (Table 1). Conclusion We demonstrate the spectrum of germline aberrations associated with predisposition to hematological malignancies and outline the phenotypic heterogeneity of clonal transformation. The advent of NGS allows identification of clonal progression earlier than morphological changes, with mutations in ASXL1 and RAS pathway genes being commonly implicated. This study supports the universal development of dedicated germline predisposition clinics. Disclosures Pruthi: CSL Behring: Honoraria; Genentech Inc.: Honoraria; Bayer Healthcare: Honoraria; HEMA Biologics: Honoraria; Instrumentation Laboratory: Honoraria; Merck: Honoraria.

BackgroundPlatelet (PLT) transfusions are an important component of hemostatic resuscitation. The AABB has published several guidelines recommending that PLT units should not be infused through blood warming devices.Study Design and MethodsThirty‐one units of hospital blood bank apheresis PLTs were obtained. PLT‐rich plasma (PRP) aggregometry and thromboelastography (TEG) were performed on the unit samples before and after the units were infused through a Ranger blood/fluid warming device.ResultsThere were no differences in any of the aggregometry results before and after infusion of the PLTs through the blood warmer (all P > .32). There was a significant reduction in the TEG maximum amplitude (MA) of 69.8 ± 7.9 mm before and 66.0 ± 8.8 mm after (P < .001) infusion of the PLTs through the blood warmer and α angle 61.8 ± 9.4° before and 59.3 ± 8.2° after (P = .044) infusion of the PLTs through the blood warmer, although both mean values were within normal range for the TEG and not clinically significant. There were very good correlations of aggregometry and TEG results before and after infusion of the PLTs through the blood warmer device.ConclusionThis study did not demonstrate significant deleterious effect on PLT function from infusing apheresis PLT units through a blood warming device by PRP aggregometry. We did detect a statistically significant—but not clinically significant—reduction in TEG MA and α angle. The prohibition of transfusing PLT units though the Ranger blood warming device is not indicated.