How do I implement diagnostic management teams in transfusion medicine?

Diagnostic management teams (DMTs) were conceptualized approximately twenty years ago in response to increasing subspecialization in medicine. DMTs are a collaboration between diagnostic experts and clinicians that aim to improve accurate and timely diagnosis and treatment of disease. Diagnostic experts provide their expertise in the increasingly complex realm of laboratory testing and interpretation of those test results to guide appropriate test utilization for individual patients. Not only can this approach improve patient care and safety, but DMTs also decrease healthcare costs by reducing unnecessary testing and potential diagnostic errors. Following the DMT construct and principles along with the 2015 National Academy of Medicine recommendations, our transfusion medicine (TM) service streamlined the workup and management of platelet refractory (PR) patients by developing and implementing a formal PR laboratory consult. The goals of this DMT and consult are to improve diagnostic management of PR patients and to decrease delays in providing these patients with appropriate and compatible platelet units. A comprehensive interpretation of test results is directly uploaded to the patient's electronic medical record (EMR), which is associated with a CPT code allowing for compensation for the PR evaluation. Herein we describe the development of and experience with the DMT since its implementation.

Characterization of Ebola convalescent plasma donor immune response and psoralen treated plasma in the United States.

BACKGROUND: In 2014, passive immunization by transfusion of Ebola convalescent plasma (ECP) was considered for treating patients with acute Ebola virus disease (EVD). Early Ebola virus (EBOV) seroconversion confers a survival advantage in natural infection, hence transfusion of ECP plasma with high levels of neutralizing EBOV antibodies is a potential passive immune therapy. Techniques to reduce the risk of other transfusion-transmitted infections (TTIs) are warranted as recent ECP survivors are ineligible as routine blood donors. As part of an ongoing clinical trial to evaluate the safety and effectiveness of ECP, the impact of amotosalen/UVA pathogen reduction technology (PRT) on EBOV antibody characteristics was examined. STUDY DESIGN AND METHODS: Serum and plasma samples were collected from EVD-recovered subjects at multiple timepoints and evaluated by ELISA for antibodies to recombinant EBOV glycoprotein (GP) and irradiated whole EBOV antigen, as well as for EBOV microneutralization, classic plaque reduction neutralization test (PRNT) and EBOV pseudovirion neutralization assay (PsVNA) activity. RESULTS: Six subjects donated 40 individual ECP units. Substantial antibody titers and neutralizing activity results were demonstrated but were generally lower for the ACD plasma samples compared to the serum samples. Anti-EBOV titers by all assays remained essentially unchanged after PRT. CONCLUSION: Treatment of ECP with PRT to reduce the risk of TTI did not significantly reduce EBOV IgG antibody titers or neutralizing activity. Although ECP was used in the treatment of repatriated patients, no PRT units from this study were transfused to EVD patients. This inventory of PRT-treated ECP is currently available for future clinical evaluation.

Multiple hemolytic transfusion reactions misinterpreted as severe vaso-occlusive crisis in a patient with sickle cell disease.

BACKGROUND: Hemolytic transfusion reactions are a rare, yet serious complication of red blood cell (RBC) transfusion. Patients with sickle cell disease (SCD) are at an increased risk for such reactions, because they are prone to make alloantibodies against transfused RBCs, complicating this integral part of their disease management. These reactions may be missed, and the patient's state may be attributed to vaso-occlusive crisis (VOC), with misguided therapy ensuing. CASE REPORT: Herein, we report the clinical course of a patient with complex SCD with a delayed hemolytic transfusion reaction, followed by multiple acute hemolytic transfusion reactions mistaken for severe VOC. These reactions were diagnosed on retrospective review of the patient's clinical course in consult with the transfusion medicine service. Optimal immunosuppressive therapy ensued and resulted in the stabilization of the anemia and hemolysis laboratory values. Despite these efforts, the patient died 2 months after admission. CONCLUSION: This case provides insight into some of the challenges of managing patients with SCD with multiple comorbidities. Hemolytic transfusion reactions can be difficult to diagnose and may be overlooked in patients with SCD with severe VOC.

Challenges in the treatment and prevention of delayed hemolytic transfusion reactions with hyperhemolysis in sickle cell disease patients.

BACKGROUND: Delayed hemolytic transfusion reactions (DHTRs) are serious complications of RBC transfusion that can occur in previously alloimmunized patients. Patients who require episodic transfusions during heightened inflammatory states, such as patients with sickle cell disease (SCD), are particularly prone to alloimmunization and developing DHTRs with hyperhemolysis. While efforts to mitigate these hemolytic episodes via immunosuppressive drugs can be employed, the relative efficacy of various treatment options remains incompletely understood. CASE REPORTS: In this study, we explored five patients with SCD and multiple RBC alloantibodies who received various forms of immunosuppressive therapy in an attempt to prevent or treat severe DHTRs. RESULTS: The clinical course for these five patients provides insight into the difficulty of effectively treating and preventing DHTRs in patients with SCD with currently available immunosuppressive therapies. CONCLUSION: Based on our experience, and the current literature, it is difficult to predict the potential impact of various immunosuppressive therapies when seeking to prevent or treat DHTRs. Future mechanistic studies are needed to identify the optimal treatment options for DHTRs in the presence or absence of distinct alloantibodies in patients with SCD.

Caring for patients with Ebola virus disease: Are U.S. biocontainment centers ready for the next outbreak?

The 2014 West African Ebola virus disease (EVD) outbreak is the largest and deadliest EVD epidemic to date, resulting in fivefold more cases than all other outbreaks combined. This outbreak was particularly devastating to healthcare workers in West Africa and resulted in several EVD patients being medically evacuated for treatment in the U.S. and Europe. Governmental agencies provide recommendations for triaging and testing patients with EVD, however best laboratory practices are still unknown and are very resource dependent.

Transfusion-Transmitted Infections: an Update on Product Screening, Diagnostic Techniques, and the Path Ahead.

The mandated testing of blood components for infectious diseases, to prevent transfusion-transmitted infections (TTIs), began in the 1950s. Since then, changes in predonation questionnaires and advances in testing techniques have afforded more sensitive and specific tests for pathogens, in addition to allowing earlier detection. Given that these approaches have very low but detectable failure rates, the recent development and implementation of proactive pathogen reduction approaches is the new forefront of TTI prevention strategies. With globalization and the ability of pathogens to evolve rapidly, continuous redefining of testing standards and laboratory techniques is paramount for maintaining a safe blood supply.

Current state of transfusion practices for ABO-incompatible pediatric heart transplant patients in the United States and Canada.

BACKGROUND: ABO compatibility restriction on solid organ transplantation limits organ availability. In an effort to increase organ availability, pediatric ABO-incompatible heart transplants (ABOiHT) are now performed with similar outcomes to ABO-compatible transplants. Transfusion support can be challenging and currently there are no standard guidelines for blood product support, ABO isohemagglutinin (IH) titer cutoffs for transplant eligibility, or therapeutic intervention for these patients. The study aim was to survey current blood bank and antibody reduction practices for pediatric ABOiHT in the United States and Canada. STUDY DESIGN AND METHODS: A Web-based survey was sent to 50 US and Canadian pediatric blood bank directors. Participants were queried regarding pre-, intra-, and postoperative blood product support; ABO IH titer testing; and antibody reduction practices in ABOiHT recipients. RESULTS: We analyzed 21 responses from US and Canadian centers that perform pediatric ABOiHT. There is wide variation in the type of blood products transfused and the modification of these products among respondents in the pre-, intra-, and postoperative settings. The frequency of testing ABO IH titers, implementing therapeutic intervention, and the type of therapeutic intervention also vary greatly among the institutions. CONCLUSION: Transfusion support of children with ABOiHT varies widely among blood banks in the United States and Canada. The choice of blood products and modifications utilized, titer thresholds for organ selection and medical decision points, and antibody reduction strategies are not standardized from center to center. As pediatric ABOiHTs become more common, a better understanding of optimal transfusion support and therapeutic intervention is needed.

Transfusion-transmitted malaria masquerading as sickle cell crisis with multisystem organ failure.

BACKGROUND: Fever accompanying vaso-occlusive crisis is a common presentation in patients with sickle cell disease (SCD) and carries a broad differential diagnosis. Here, we report a case of transfusion-transmitted malaria in a patient with SCD presenting with acute vaso-occlusive crisis and rapidly decompensating to multisystem organ failure (MSOF). CASE REPORT: An 18-year-old African American male with SCD was admitted after multiple days of fever and severe generalized body pain. He received monthly blood transfusions as stroke prophylaxis. A source of infection was not readily identified, but treatment was initiated with continuous intravenous fluids and empiric antibiotics. The patient developed acute renal failure, acute hypoxic respiratory failure, and shock. He underwent red blood cell (RBC) exchange transfusion followed by therapeutic plasma exchange and continuous veno-venous hemodialysis. A manual peripheral blood smear revealed intraerythrocytic inclusions suggestive of Plasmodium, and molecular studies confirmed Plasmodium falciparum infection. Intravenous artesunate was given daily for 1 week. A look-back investigation involving two hospitals, multiple blood suppliers, and state and federal public health departments identified the source of malaria as a unit of RBCs transfused 2 weeks prior to admission. CONCLUSIONS: Clinical suspicion for transfusion-related adverse events, including hemolytic transfusion reactions and transfusion-transmitted infections, should be high in typically and atypically immunocompromised patient populations (like SCD), especially those on chronic transfusion protocols. Manual blood smear review aids in the evaluation of patients with SCD presenting with severe vaso-occlusive crisis and MSOF and can alert clinicians to the need for initiating aggressive therapy like RBC exchange and artesunate therapy.

Stability of anti-A blood group titers among blood group B renal transplant candidates.

BACKGROUND: As deceased donor kidney allocation is based in part on blood type compatibility, group B candidates are disadvantaged due to their disproportionate representation on the wait list compared to the group B donor pool. To mitigate this discrepancy, group B candidates can receive group A2 or A2 B donor kidneys if their anti-A titers are below a predetermined cutoff. Currently, eligibility is reverified quarterly to UNet based on individual center protocols, which can vary due to a lack of set guidelines for monitoring ABO titers in these patients. Our goal was to assess the stability of anti-A titers in blood group B renal transplant candidates over time to provide data that could aid in the development of standardized ABO titer protocols. STUDY DESIGN AND METHODS: Titers performed between January 2011 and December 2015 were assessed for 191 group B patients with two or more documented titers. RESULTS: Fifty patients (26%) were ineligible, as the first titer exceeded the cutoff of 8. Of the remaining 141 patients, 19 (13%) became ineligible as the second titer exceeded 8. Thirty-nine patients (28%) had no change in titer between samples, while 71 (50%) had a titer change that never exceeded 8. Only 12 patients (8.5% of total) experienced a titer change that affected eligibility after the second test. CONCLUSION: Although patients experience some variability in anti-A titers over time, in most cases, stability did not affect candidate eligibility. Our results indicate that regular testing beyond the second titer may be unnecessary and represent test overutilization.

An Overview of Heparin Monitoring with the Anti-Xa Assay.

Heparin remains a critical therapy in hospitalized patients requiring anticoagulation. Unfractionated heparin (UFH) mediates its therapeutic effect by binding to antithrombin (AT) and inhibiting thrombin and FXa, as well as other serine proteases. Because of its complex pharmacokinetics, monitoring UFH therapy is required, which is usually achieved with either the activated partial thromboplastin time (APTT) or the anti-factor Xa (anti-Xa) assay. Low molecular weight heparin (LMWH) is fast replacing UFH, as it has a more predictable response, negating the need for routine monitoring in most cases. When required, the anti-Xa assay is used for monitoring of LMWH. The APTT has many notable limitations when used for heparin therapeutic monitoring, including biologic, preanalytical, and analytical issues. With its increasing availability, the anti-Xa assay is appealing as it is less affected by patient factors (e.g., acute-phase reactants, lupus anticoagulants, consumptive coagulopathies), known to interfere with the APTT. The anti-Xa assay has shown additional benefits, such as faster time to achieve therapeutic levels, more consistent therapeutic levels, less dose adjustments, and, overall, less tests performed during therapy. However, poor interlaboratory agreement has been observed among anti-Xa reagents, highlighting that further work needs to be done to standardize this assay for use in patient heparin monitoring.

A Sticky Situation: Variable Agreement Between Platelet Function Tests Used to Assess Anti-platelet Therapy Response.

Background: Platelet function testing to monitor antiplatelet therapy is important for reducing thromboembolic complications, yet variability across testing methods remains challenging. Here we evaluated the agreement of four different testing platforms used to monitor antiplatelet effects of aspirin (ASA) or P2Y12 inhibitors (P2Y12-I). Methods: Blood and urine specimens from 20 patients receiving dual antiplatelet therapy were analyzed by light transmission aggregometry (LTA), whole blood aggregometry (WBA), VerifyNow PRUTest and AspirinWorks. Result interpretation based on pre-defined cutoff values was used to calculate raw agreement indices, and Pearson's correlation coefficient determined using individual units of measure. Results: Agreement between LTA and WBA for P2Y12-I-response was 60% (r = 0.65, high-dose ADP; r = 0.75, low-dose ADP). VerifyNow agreed with LTA in 75% (r = 0.86, high-dose ADP; r = 0.75, low-dose ADP) and WBA in 55% (r = 0.57) of cases. Agreement between LTA and WBA for ASA-response was 45% (r = 0.09, high-dose collagen WBA; r = 0.19, low-dose collagen WBA). AspirinWorks agreed with LTA in 60% (r = 0.32) and WBA in 35% (r = 0.02, high-dose collagen WBA; r = 0.08, low-dose collagen WBA) of cases. Conclusions: Overall agreement varied from 35 to 75%. LTA and VerifyNow demonstrated the highest agreement for P2Y12-I-response, followed by moderate agreement between LTA and WBA. LTA and AspirinWorks showed moderate agreement for aspirin response, while WBA showed the weakest agreement with both LTA and AspirinWorks. The results from this study support the continued use of LTA for monitoring dual antiplatelet therapy, with VerifyNow as an appropriate alternative for P2Y12-I-response. Integration of results obtained from these varied testing platforms with patient outcomes remains paramount for future studies.

Identification of a recurrent pattern of false-positivity by Luminex HLA MHC class I single antigen bead testing.

Previously, a distinct MHC class II Luminex-single antigen bead (SAB) pattern was described and attributed to antibodies targeting denatured antigens. In this study, we describe a distinct MHC class I reactivity pattern observed in 1.8% (105/5992) of samples resulted in 2017. The pattern displays reactivity to the following Luminex-SABs: HLA-A*33:03, A*36:01, A*80:01, B*54:01, B*53:01, C*06:02, C*07:02, C*18:02, C*14:02, C*03:03, C*03:04, and C*15:02. This pattern was identified in patients with no sensitization history, negative FlowPRA results, and antibody to self-antigen(s). Epitope analysis failed to reveal a common determinant(s) to explain this pattern of reactivity. Additionally, we found this pattern to be prevalent in female patients (62%) and also those with systemic lupus erythematosus (62%). Given these findings, we speculate this pattern likely represents false-positive reactivity, possibly due to antibody targeting denatured antigens or a specific peptide, molecular mimicry, autoimmunity, or a combination thereof.

The impact of transfused blood products on deceased donor HLA typing.

Accurate deceased donor HLA typing assumes that the blood sample tested contains only DNA from the organ donor. Prior to procurement, many organ donors are transfused at least one unit of red blood cells (RBC). Non-organ donor DNA acquired from transfusions may result in incorrect and/or ambiguous HLA typing. To address this question, we investigated the impact of RBC transfusion on organ donor HLA typing by using different in vitro transfusion models: leukoreduced (LR) and non-LR RBCs. Various quantities of LR and non-LR RBCs were added to normal peripheral blood and HLA typing was performed by real time PCR. Our results show that HLA typing of deceased donors can be impacted dependent upon the type and quantity of transfused RBCs. Importantly, if LR RBCs are given, HLA typing is unlikely to be affected, precluding the need to delay typing and obtain an alternative source of donor DNA.

(F)Utility of the physical crossmatch for living donor evaluations in the age of the virtual crossmatch.

Flow cytometric crossmatches (FCXM) are routinely performed to support living-donor renal transplantation. While long a laboratory mainstay, a physical crossmatch is costly, time consuming, and frequently poses interpretative conundrums with both false-positive and false- negative results. Given the increased utilization of the virtual crossmatch (vXM) in the deceased donor setting, our aim was to assess its utility in living donor evaluations. We reviewed 100 living donor FCXMs and retrospectively performed a vXM for each pair. Seventy-five (75) cases were concordant, (i.e., FCXM-/vXM- or FCXM+/vXM+) while 25 cases were discordant; Five were vXM+/FCXM- and 20 were FCXM+/vXM-. Since donor-specific antibodies (DSA) were not detected in the 20 FCXM+/vXM- cases, these were interpreted as false-positive, i.e., due to non-HLA antibodies. Importantly, none of these patients, when transplanted across a positive FCXM, experienced early antibody mediated rejection or subsequently developed HLA DSA. These data reveal that, for the vast majority of living donor evaluations, a vXM is an acceptable vetting procedure.

Human Papillomavirus.

Individuals with inherited immunodeficiencies, autoimmune disorders, organ or bone marrow transplantation, or infection with human immunodeficiency virus (HIV) are at increased risk of infection with both low-risk and high-risk human papillomavirus (HPV) types. Chronic immunosuppression provides an environment for persistent HPV infection which carries a higher risk of malignant transformation. Screening guidelines have been developed or advocated for processes that have detectable premalignant lesions, such as anal cancer or cervical cancer. For other anatomic locations, such as cutaneous, penile, and oropharyngeal, a biopsy of suspicious lesions is necessary for diagnosis. HPV cannot be cultured from clinical specimens in the laboratory, and diagnosis relies on cytologic, histologic, or molecular methods.