Norgan, Andrew P

AbstractBackgroundPrimary cold agglutinin disease (CAD) is a monoclonal antibody (M‐protein) and complement‐mediated chronic hemolytic disease process. Antibody glycosylation can play a role in both antibody half‐life and complement fixation. Recently, M‐protein light chain (LC) glycosylation has been shown to be associated with AL amyloidosis. We hypothesized that M‐protein LC glycosylation is also associated with cold agglutinin (CA) titers and CA‐mediated hemolysis.Study Design and MethodsA cross‐sectional study of patients undergoing CA titer evaluation underwent mass spectrometric analysis for M‐proteins and M‐protein LC glycosylation. A subset of serum samples also underwent evaluation for the ability to trigger cold hemolysis in vitro. M‐protein and M‐protein LC glycosylation rates were compared across CA titer groups, clinical diagnosis, direct antiglobulin testing (DAT) results, and cold in vitro hemolysis rates.ResultsBoth M‐protein and M‐protein LC glycosylation rates significantly differed across CA titer groups with the highest rates in those with elevated CA titers. M‐protein LC glycosylation occurred almost exclusively on IgM kappa M‐proteins and was significantly associated with positive DAT results and a clinical diagnosis of CAD. Cold in vitro hemolysis was demonstrated in two patients who both had a CA titer of more than 512 but there was no significant association with CA titer group or M‐protein LC glycosylation status.ConclusionM‐protein LC glycosylation is significantly associated with higher CA titer levels. Given the role that antibody glycosylation can play in antibody half‐life and complement fixation, further studies are needed to clarify the effects of LC glycosylation within the context of CAD.

Abstract Objectives Error simulation models have been used to understand the relationship between analytical performance and clinical outcomes. We developed an error simulation model to understand the effects of method bias and precision on misclassification rate for neonatal hyperbilirubinemia using an age-adjusted risk assessment tool. Methods For each of 176 measured total bilirubin (TSB M ) values, 10,000 simulated total bilirubin (TB S ) values were generated at each combination of bias and precision conditions for coefficient of variation (CV) between 1 and 15%, and for biases between −51.3 μmol/L and 51.3 μmol/L (−3 and 3 mg/dL) fixed bias. TB S values were analyzed to determine if they were in the same risk zone as the TSB M value. We then calculated sensitivity and specificity for prediction of ≥75th percentile for postnatal age values as a function of assay bias and precision, and determined the rate of critical errors (≥95th percentile for age TSB M with <75th percentile TB S ). Results A sensitivity >95% for predicting ≥75th percentile bilirubin values was observed when there is a positive fixed bias of greater than 17.1 μmol/L (1.0 mg/dL) and CV is maintained ≤10%. A specificity >70% for predicting <75th percentile bilirubin values was observed when positive systematic bias was 17.1 μmol/L (1 mg/dL) or less at CV ≤ 10%. Critical errors did not occur with a frequency >0.2% until negative bias was −17.1 μmol/L (−1 mg/dL) or lower. Conclusions A positive systematic bias of 17.1 μmol/L (1 mg/dL) may be optimal for balancing sensitivity and specificity for predicting ≥75th percentile TSB values. Negative systematic bias should be avoided to allow detection of high risk infants and avoid critical classification errors.

Shotgun metagenomic sequencing can detect nucleic acids from bacteria, fungi, viruses, and/or parasites in clinical specimens; however, little data exist to guide its optimal application to clinical practice. We retrospectively reviewed results of shotgun metagenomic sequencing testing requested on cerebrospinal fluid samples submitted to an outside reference laboratory from December 2017 through December 2019. Of the 53 samples from Mayo Clinic patients, 47 were requested by neurologists, with infectious diseases consultation in 23 cases.

AbstractBackgroundPlatelet (PLT) transfusion refractoriness increases bleeding complications, hospital stays, and PLT inventory usage. Immune‐mediated refractoriness can be evaluated for using a physical PLT crossmatch with ABO‐compatible inventory and, if positive, managed with HLA‐compatible PLT inventory and donors. Manual completion of these complex tasks can be time‐consuming and potentially error‐prone. This study was conducted to determine if a Web‐based software application could improve process efficiency and accuracy.Study Design and MethodsWorkflow analysis was performed to identify process, data, and analytic requirements for a software application for three PLT transfusion‐refractoriness associated tasks: (a) physical PLT crossmatch inventory selection, (b) HLA‐compatible inventory selection, and (c) HLA‐compatible donor selection. After software application development, a comparison study was performed over 10 consecutive days, with each task performed manually and with the software application (Platelet Virtual Crossmatch [PLT VXM]) for a different unique immune‐mediated PLT transfusion–refractory recipient. Task completion time, number of incompatible units/donors presented, and number of documentation errors were compared.ResultsPLT VXM is a Web‐based software application developed using R and the Shiny Web application framework. PLT VXM significantly reduced median task completion times by 4.5 (49%), 11.2 (79%), and 59.1 minutes (94%), respectively. PLT VXM did not present any incompatible PLT units or donors for user consideration. PLT VXM also had a lower number of documentation errors than the manual process, and none of these documentation errors were software generated.ConclusionComputer‐aided evaluation and management of immune‐mediated PLT transfusion–refractory recipients can significantly improve workflow and reduce manual errors in this complex process.

Context.— Preanalytic errors, including specimen labeling errors and specimen loss, occur frequently during specimen collection, transit, and accessioning. Radio-frequency identification tags can decrease specimen identification and tracking errors through continuous and automated tracking of specimens. Objective.— To implement a specimen tracking infrastructure to reduce preanalytic errors (specimen mislabeling or loss) between specimen collection and laboratory accessioning. Specific goals were to decrease preanalytic errors by at least 70% and to simultaneously decrease employee effort dedicated to resolving preanalytic errors or investigating lost specimens. Design.— A radio-frequency identification specimen-tracking system was developed. Major features included integral radio-frequency identification labels (radio-frequency identification tags and traditional bar codes in a single printed label) printed by point-of-care printers in collection suites; dispersed radio-frequency identification readers at major transit points; and systems integration of the electronic health record, laboratory information system, and radio-frequency identification tracking system to allow for computerized physician order entry driven label generation, specimen transit time tracking, interval-based alarms, and automated accessioning. Results.— In the 6-month postimplementation period, 6 mislabeling events occurred in collection areas using the radio-frequency identification system, compared with 24 events in the 6-month preimplementation period (75% decrease; P = .001). In addition, the system led to the timely recovery of 3 lost specimens. Labeling expenses were decreased substantially in the transition from high-frequency to ultrahigh frequency radio-frequency identification tags. Conclusions.— Radio-frequency identification specimen tracking prevented several potential specimen-loss events, decreased specimen recovery time, and decreased specimen labeling errors. Increases in labeling/tracking expenses for the system were more than offset by time savings and loss avoidance through error mitigation.

Abstract Objectives Pathogenic free-living amebae (FLAs) cause skin, ocular, and central nervous system (CNS) infections with significant morbidity and mortality. Diagnosis of FLA infections by pathologic examination of tissue sections can be aided using molecular assays. This study investigated the performance characteristics of a multiplex real-time polymerase chain reaction (PCR) assay (FLA-PCR) for detection and differentiation of FLAs in clinical specimens. Methods FLA-PCR was performed on 39 human specimens comprising one cutaneous, 14 corneal, and 24 CNS formalin-fixed, paraffin-embedded (FFPE) tissues with a histopathologic diagnosis of FLA infection and four CNS FFPE tissues with inflammation but no evidence of FLAs. In addition, clinical specificity and assay limit of detection were determined. Results FLA detection sensitivities ranged from 79% to 84% in FFPE tissues. No cross-reactivity was observed. Conclusions While sensitivity is limited, FLA-PCR assay may serve as a useful adjunct for detection or confirmation of FLA infections in FFPE tissues.

Cytapheresis (removal of cellular blood components) has been employed for treatment of infectious diseases since the 1960s. Techniques have included thrombocytapheresis (buffy coat apheresis) for loiasis, erythrocytapheresis for malaria and babesiosis, and leukocytapheresis for pertussis‐associated lymphocytosis. Published data on these applications is largely limited to case level data and small observational studies; as such, recommendations for or against the use of cytapheresis in the treatment of infections have been extrapolated from these limited (and at times flawed) data sets. Consequently, utilization of cytapheresis in many instances is not uniform between institutions, and typically occurs at the discretion of treating medical teams. This review revisits the existing literature on the use of cytapheresis in the treatment of four infections (loasis, malaria, babesiosis, and pertussis) and examines the rationale underlying current treatment recommendations concerning its use.

A variety of arthropods, protozoa, and helminths infect the skin and subcutaneous tissues and may be identified by anatomic pathologists in standard cytology and histology preparations. The specific organisms seen vary greatly with the patient’s exposure history, including travel to or residence in endemic countries. Arthropods are the most commonly encountered parasites in the skin and subcutaneous tissues and include Sarcoptes scabei, Demodex species, Tunga penetrans, and myiasis-causing fly larvae. Protozoal parasites such as Leishmania may also be common in some settings. Helminths are less often seen, and include round worms (eg, Dirofilaria spp.), tapeworms (eg, Taenia solium, Spirometra spp.), and flukes (eg, Schistosoma spp.). This review covers the epidemiologic and histopathologic features of common parasitic infections of the skin and subcutaneous tissues.

BACKGROUND Platelet transfusion–refractoriness is a challenging and expensive clinical scenario seen most often in patients with hematologic malignancies. Although the majority of platelet transfusion–refractory cases are due to nonimmune causes, a significant minority are caused by alloimmunization against Class I human leukocyte antigens (HLAs) or human platelet antigens (HPAs). Such platelet transfusion–refractory patients can be effectively managed with appropriate antigen‐negative products. STUDY DESIGN AND METHODS Our institution has developed a diagnostic and management algorithm for the platelet transfusion–refractory patient with an early focus on identifying those cases caused by immune‐mediated factors. Using physical platelet cross‐matches to initially classify platelet transfusion–refractory patients as immune‐mediated or not, cross‐match–compatible inventory is then provided to immune‐mediated patients, whereas subsequent HLA (with or without HPA) testing is performed. RESULTS Our blood donor program performs Class I HLA typing of all repeat platelet donors to facilitate the identification of antigen‐negative platelet units (virtual cross‐matching) as well as the recruitment of HLA‐matched donors. The platelet transfusion–refractoriness algorithm realizes an initial net cost savings once two apheresis platelets are saved from use for each newly identified, immune‐mediated platelet transfusion–refractory patient. CONCLUSION An algorithm utilizing physical platelet cross‐matches, Class I HLA and HPA antibody testing, and upfront Class I HLA typing of platelet donors leads to overall resource savings and improved clinical management for platelet transfusion–refractory patients.