Pruthi, Rajiv K.

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.

Abstract Heparin-induced thrombocytopenia (HIT) is a life-threatening, prothrombotic, antibody-mediated disorder. To maximize the likelihood of recovery, early and accurate diagnosis is critical. Widely available HIT assays, such as the platelet factor 4 (PF4) heparin enzyme-linked immunosorbent assay (ELISA) lack specificity, and the gold-standard carbon 14–labeled serotonin release assay (SRA) is of limited value for early patient management because it is available only through reference laboratories. Recent studies have demonstrated that pathogenic HIT antibodies selectively activate PF4-treated platelets and that a technically simpler assay, the PF4-dependent P-selectin expression assay (PEA), may provide an option for rapid and conclusive results. Based upon predefined criteria that combined 4Ts scores and HIT ELISA results, 409 consecutive adults suspected of having HIT were classified as disease positive, negative, or indeterminate. Patients deemed HIT indeterminate were considered disease negative in the primary analysis and disease positive in a sensitivity analysis. The ability of PEA and SRA to identify patients judged to have HIT was compared using receiver operating characteristic curve statistics. Using these predefined criteria, the diagnostic accuracy of PEA was high (area under the curve [AUC], 0.94; 95% confidence interval [CI], 0.87-1.0) and similar to that of SRA (AUC, 0.91; 95% CI, 0.82-1.0). In sensitivity analysis, the AUCs of PEA and SRA were also similar at 0.88 (95% CI, 0.78-0.98) and 0.86 (95% CI, 0.77-0.96), respectively. The PEA, a technically simple nonradioactive assay that uses ∼20-fold fewer platelets compared with the SRA, had high accuracy for diagnosing HIT. Widespread use of the PEA may facilitate timely and more effective management of patients with suspected HIT.

7039 Background: Erythropoiesis-stimulating agents are known to increase the risk for VTE events, especially in patients with underlying malignancies. However, there is a paucity of information on other hematopoietic growth factors such as granulocyte colony-stimulating factor (GSCF) granulocyte-macrophage colony stimulating factor (GM-CSF) AMD 3001 and risk for VTE. Methods: Between January 2000 and October 2008, a total of 631 patients underwent peripheral blood stem cell mobilization (PBSCM) using either GCSF, GMCSF, cyclophosphamide, AMD 3100, or with any of the above combination. We included only patients with a diagnosis of AL amyloidosis (AL), multiple myeloma (MM) Hodgkin's lymphoma (HL) and non Hodgkin's lymphoma (NHL). Patients’ demographic details and diagnosis of VTE were collected from electronic medical records. Results: Of the 631 patients who underwent PBSCM the median age of the patients was 57 years (range 17–77). 448 patients (71%) received single agent GCSF, 82 (13%) received combination of GMCSF and cyclophosphamide, 52 (8%) received cyclophosphamide and GCSF, 30 patients received a combination of GMCSF and GCSF, 10 (1.5%) patients received GCSF and AMD 3100. Of the 631 patients, 278 (44%) MM, 209 (33%) NHL, 114 (18%) AL, and 20 (3%) had HL. We found 7 (1.1%) patients with symptomatic VTE occurring between administration of growth factors and stem cell transplant. The median duration from the administration of growth factors to detection of VTE was 5 days (range 1–30). Two AL,3 MM and 2 NHL. Of the 7 patients, 2 patients had pulmonary embolism and 1 patient developed deep vein thrombosis. Two patients with AL developed heparin induced thrombocytopenia (HIT). The remaining 4 patients developed symptomatic catheter related thrombosis. Only 1 patient had past history of VTE. Of the 7 patients, 5 received GCSF alone, 1 received GMCSF, and cyclophosphamide, 1 received GCSF and cyclophosphamide. Of the 4 patients who developed catheter related thrombosis, catheter was removed in 2 patients. None of the patients developed VTE related morality. Conclusions: The risk for symptomatic VTE during PBSCM is low. HIT should be considered as a possible cause for VTE in patients undergoing PBSCM. No significant financial relationships to disclose.

Temporal inference from laboratory testing results and triangulation with clinical outcomes extracted from unstructured electronic health record (EHR) provider notes is integral to advancing precision medicine. Here, we studied 246 SARS-CoV-2 PCR-positive (COVID pos ) patients and propensity-matched 2460 SARS-CoV-2 PCR-negative (COVID neg ) patients subjected to around 700,000 lab tests cumulatively across 194 assays. Compared to COVID neg patients at the time of diagnostic testing, COVID pos patients tended to have higher plasma fibrinogen levels and lower platelet counts. However, as the infection evolves, COVID pos patients distinctively show declining fibrinogen, increasing platelet counts, and lower white blood cell counts. Augmented curation of EHRs suggests that only a minority of COVID pos patients develop thromboembolism, and rarely, disseminated intravascular coagulopathy (DIC), with patients generally not displaying platelet reductions typical of consumptive coagulopathies. These temporal trends provide fine-grained resolution into COVID-19 associated coagulopathy (CAC) and set the stage for personalizing thromboprophylaxis.