Zoonotic Bacterial Infections Triggering Cytokine Storm Syndrome.

Zoonotic infections can result in life-threatening complications that can manifest with hemophagocytic lymphohistiocytosis (HLH)/cytokine storm syndrome (CSS). Bacteria constitute the largest group of zoonotic infection-related HLH cases. The growing list of zoonotic bacterial infections associated with HLH/CSS include Brucella spp., Rickettsia spp., Ehrlichia, Coxiella burnetii, Mycobacterium spp., and Bartonella spp. Patients most commonly present with fever, cytopenias, hepatosplenomegaly, myalgias, and less frequently with rash, jaundice, and lymphadenopathy.

Evaluation of an automated von Willebrand factor glycoprotein IbM activity assay compared with 3 alternative von Willebrand factor activity assays.

Background: To overcome deficiencies of the traditional von Willebrand factor (VWF) ristocetin cofactor activity assay (VWF:RCo), several automated assays for VWF platelet-binding activity have been developed. Information on the performance of these assays and their diagnostic utility remains limited. Objectives: To validate the VWF:glycoprotein IbM assay INNOVANCE VWF Ac and compare it with an automated VWF:RCo assay as well as with an automated assay and a manual VWF:Ab assay and to generate reference ranges and analyze reproducibility of the VWF:glycoprotein IbM assay. Methods: Clinical sites enrolled healthy subjects and patients representing the intended use population; VWF activity assays were performed, and results were analyzed. The performance of the INNOVANCE VWF Ac assay was also compared between the BCS XP System and the CS-2500 and CS-5100 analyzers. Results: The INNOVANCE VWF Ac assay correlated well with the VWF:RCo assay and the automated HemosIL VWF:Ab assay, with Pearson coefficients of >.9 and a predicted bias of ≤5.0 IU/dL at VWF levels of 30 IU/dL and ≤5.8 IU/dL at the levels of 50 IU/dL, but correlation and bias were not as good when compared with the REAADS manual VWF:Ab assay. Reference ranges observed for healthy subjects correlated well with previously published findings. Reproducibility of the INNOVANCE VWF Ac assay on the BCS XP System and the CS analyzers was excellent, as was correlation among devices. Conclusion: The characteristics of the INNOVANCE VWF Ac assay regarding comparability with other VWF activity assays, reference ranges, and precision support the use of this assay for evaluation of patients with concern for von Willebrand disease.

Predicting Postoperative Troponin in Patients Undergoing Elective Hip or Knee Arthroplasty: A Comparison of Five Cardiac Risk Prediction Tools.

Background: Elderly patients undergoing hip or knee arthroplasty are at a risk for myocardial injury after noncardiac surgery (MINS). We evaluated the ability of five common cardiac risk scores, alone or combined with baseline high-sensitivity cardiac troponin I (hs-cTnI), in predicting MINS and postoperative day 2 (POD2) hs-cTnI levels in patients undergoing elective total hip or knee arthroplasty. Methods: This study is ancillary to the Genetics-InFormatics Trial (GIFT) of Warfarin Therapy to Prevent Deep Venous Thrombosis, which enrolled patients 65 years and older undergoing elective total hip or knee arthroplasty. The five cardiac risk scores evaluated were the atherosclerotic cardiovascular disease calculator (ASCVD), the Framingham risk score (FRS), the American College of Surgeon's National Surgical Quality Improvement Program (ACS-NSQIP) calculator, the revised cardiac risk index (RCRI), and the reconstructed RCRI (R-RCRI). Results: None of the scores predicted MINS in women. Among men, the ASCVD (C-statistic of 0.66; p=0.04), ACS-NSQIP (C-statistic of 0.69; p=0.01), and RCRI (C-statistic of 0.64; p=0.04) predicted MINS. Among all patients, spearman correlations (r s) of the risk scores with the POD2 hs-cTnI levels were 0.24, 0.20, 0.11, 0.11, and 0.08 for the ASCVD, Framingham, ACS-NSQIP, RCRI, and R-RCRI scores, respectively, with p values of <0.001, <0.001, <0.001, 0.006, and 0.025. Baseline hs-cTnI predicted MINS (C-statistics: 0.63 in women and 0.72 in men) and postoperative hs-cTnI (r s = 0.51, p=0.001). Conclusion: In elderly patients undergoing elective hip or knee arthroplasty, several of the scores modestly predicted MINS in men and correlated with POD2 hs-cTnI.

Warfarin Dosing in Patients With CYP2C9*5 Variant Alleles.

Pharmacogenetic dosing improves the accuracy of warfarin dosing, but current pharmacogenetic dosing algorithms are less accurate in populations of African ancestry. The cytochrome P450 2C9*5 (CYP2C9*5) allele is found almost exclusively in populations of African ancestry, and in vitro studies suggest CYP2C9*5 is associated with reduced clearance of warfarin. The clinical relevance of this single-nucleotide variation (SNV) (formerly SNP) is uncertain. In this multicentered study of 2,298 patients (49% female, 35% Black) taking warfarin, we quantified the association between the CYP2C9*5 allele and warfarin requirements. The CYP2C9*5 SNV was present in 2.3% of Black and 0.07% of White patients. Without taking CYP2C9*5 into account, pharmacogenetic algorithms that include other SNVs overestimated the warfarin dose by 30% (95% confidence interval (19-40%), P < 0.001), an average of 1.87 mg/day (SD 1.64) in heterozygotes (P < 0.001). Noncarriers required a slightly (0.23 mg/day, SD 2.09) higher than predicted dose. Genotyping for CYP2C9*5 corrected the potential overdose and halved overall dosing error in heterozygotes. Patients carrying CYP2C9*5 require a clinically relevant reduction in warfarin dose. Given the potential to improve the accuracy and safety of warfarin dosing in populations of African ancestry, we have incorporated this SNV into a nonprofit website to assist warfarin initiation (www.WarfarinDosing.org).

Multiplatform Assessment of Saliva for SARS-CoV-2 Molecular Detection in Symptomatic Healthcare Personnel and Patients Presenting to the Emergency Department.

BACKGROUND: Saliva has garnered great interest as an alternative specimen type for molecular detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Data are limited on the relative performance of different molecular methods using saliva specimens and the relative sensitivity of saliva to nasopharyngeal (NP) swabs. METHODS: To address the gap in knowledge, we enrolled symptomatic healthcare personnel (n = 250) from Barnes-Jewish Hospital/Washington University Medical Center and patients presenting to the Emergency Department with clinical symptoms compatible with coronavirus disease 2019 (COVID-19; n = 292). We collected paired saliva specimens and NP swabs. The Lyra SARS-CoV-2 assay (Quidel) was evaluated on paired saliva and NP samples. Subsequently we compared the Simplexa COVID-19 Direct Kit (Diasorin) and a modified SalivaDirect (Yale) assay on a subset of positive and negative saliva specimens. RESULTS: The positive percent agreement (PPA) between saliva and NP samples using the Lyra SARS-CoV-2 assay was 63.2%. Saliva samples had higher SARS-CoV-2 cycle threshold values compared to NP swabs (P < 0.0001). We found a 76.47% (26/34) PPA for Simplexa COVID-19 Direct Kit on saliva and a 67.6% (23/34) PPA for SalivaDirect compared to NP swab results. CONCLUSION: These data demonstrate molecular assays have variability in performance for detection of SARS-CoV-2 in saliva.

Evaluation of PCR cycle threshold values by patient population with the quidel lyra SARS-CoV-2 assay.

The Lyra SARS-CoV-2 assay was the primary method for molecular testing performed at Barnes-Jewish Healthcare System in St. Louis, Missouri during the initial COVID-19 surge from mid-March to late-April 2020. We performed a retrospective analysis of 1,043 positive Lyra SARS-CoV-2 results during these 36 days to investigate associations between cycle threshold (CT)  value and patient characteristics. Total RNA were extracted from NP or OP swabs using either the EasyMag or KingFisher automated extraction systems and quantified with RotorGene Q (Qiagen) or Applied Biosystems 7500 Fast Dx thermocyclers respectively. Notably, we found lower a significant median lower CT for samples tested on the KingFisher-ABI 7500 fastDX (KF/ABI) system compared to the EasyMag/RotorGene (EM/RGQ) platform. Since 77.5% of our tests were ran on the EM/RGQ pipeline we then perform additional analysis on these values and found that C T values in outpatient care settings compared to samples obtained in the emergency department or inpatient had significantly lower C T values. These collective findings suggests a difference in viral load amongst various patient populations.

Increasing ferritin predicts early death in adult hemophagocytic lymphohistiocytosis.

INTRODUCTION: Hemophagocytic lymphohistiocytosis (HLH) is a rare syndrome of pathologic immune activation. Most studies on adult HLH have evaluated prognostic factors for overall survival; factors predicting early mortality have not been sufficiently investigated. METHODS: This was a collaborative study between Henry Ford Hospital and Barnes-Jewish Hospital. We identified all adult HLH patients with at least 2 ferritin levels within 30 days from admission. RESULTS: One-hundred twenty-four patients were identified. There were 77 males and 47 females; the median age at diagnosis was 48 years. Multivariate analysis showed that age (OR = 11.41; 95% CI:2.71-48.04; P = .001), hepatomegaly (OR = 15.68; 95% CI:3.24-75.96; P = .001), hyponatremia (OR = 5.94; 95% CI:1.76-20.1; P = .004), hypoalbuminemia (OR = 7.47; 95% CI:2.08-26.85; P = .002), and increasing ferritin levels (OR = 19.46; 95% CI:4.69-80.71; P < .001) were significant predictors of 30-day mortality. Patients with declining ferritin by more than 35% from the ferritin peak were more likely to survive the first 30 days of admission (OR = 4.33; 95% CI:1.04-18.1; P = .033). By risk stratifying our cohort, we identified changes in ferritin levels to be the most significant prognostic factor of 30-day mortality among other risk factors. Further investigating the prognostic utility of ferritin showed that increasing ferritin during the 1st week of admission (data available for 44 patients) was the only significant predictor of 30-day mortality. CONCLUSIONS: To the best of our knowledge, this is the first study reporting changes in ferritin to be a predictor for early death in adult HLH. Changes in ferritin might be a useful indicator of adult HLH disease activity and early prognosis.

Effect of Low-Intensity vs Standard-Intensity Warfarin Prophylaxis on Venous Thromboembolism or Death Among Patients Undergoing Hip or Knee Arthroplasty: A Randomized Clinical Trial.

Importance: The optimal international normalized ratio (INR) to prevent venous thromboembolism (VTE) in warfarin-treated patients with recent arthroplasty is unknown. Objective: To determine the safety and efficacy of a target INR of 1.8 vs 2.5 for VTE prophylaxis after orthopedic surgery. Design, Setting, and Participants: The randomized Genetic Informatics Trial (GIFT) of Warfarin to Prevent Deep Vein Thrombosis enrolled 1650 patients aged 65 years or older initiating warfarin for elective hip or knee arthroplasty at 6 US medical centers. Enrollment began in April 2011 and follow-up concluded in October 2016. Interventions: In a 2 × 2 factorial design, participants were randomized to a target INR of 1.8 (n = 823) or 2.5 (n = 827) and to either genotype-guided or clinically guided warfarin dosing. For the first 11 days of therapy, open-label warfarin dosing was guided by a web application. Main Outcomes and Measures: The primary outcome was the composite of VTE (within 60 days) or death (within 30 days). Participants underwent screening duplex ultrasound postoperatively. The hypothesis was that an INR target of 1.8 would be noninferior to an INR target of 2.5, using a noninferiority margin of 3% for the absolute risk of VTE. Secondary end points were bleeding and INR values of 4 or more. Results: Among 1650 patients who were randomized (mean age, 72.1 years; 1049 women [63.6%]; 1502 white [91.0%]), 1597 (96.8%) received at least 1 dose of warfarin and were included in the primary analysis. The rate of the primary composite outcome of VTE or death was 5.1% (41 of 804) in the low-intensity-warfarin group (INR target, 1.8) vs 3.8% (30 of 793) in the standard-treatment-warfarin group (INR target, 2.5), for a difference of 1.3% (1-sided 95% CI, -∞ to 3.05%, P = .06 for noninferiority). Major bleeding occurred in 0.4% of patients in the low-intensity group and 0.9% of patients in the standard-intensity group, for a difference of -0.5% (95% CI, -1.6% to 0.4%). The INR values of 4 or more occurred in 4.5% of patients in the low-intensity group and 12.2% of the standard-intensity group, for a difference of -7.8% (95% CI, -10.5% to -5.1%). Conclusions and Relevance: Among older patients undergoing hip or knee arthroplasty and receiving warfarin prophylaxis, an international normalized ratio goal of 1.8 compared with 2.5 did not meet the criterion for noninferiority for risk of the composite outcome of VTE or death. However, the trial may have been underpowered to meet this criterion and further research may be warranted. Trial Registration: ClinicalTrials.gov Identifier: NCT01006733.

Blast flagging of the Sysmex XN-10 hematology analyzer with supervised cell image analysis: Impact on quality parameters.

INTRODUCTION: The Sysmex XN-10 automated hematology analyzer (Sysmex Corporation) is routinely used in hematology laboratories to perform complete blood cell count with differential (CBC w/ diff). The sensitivity of this system for blast detection is unclear, since many prior studies evaluating the blast flagging capabilities of Sysmex XN series used the white precursor cell (WPC) channel, which is not cleared for use in the United States. METHODS: We assessed the blast flagging capabilities of the Sysmex XN-10 compared with CellaVision (a cell image analyzer)-assisted visual hematology results. We evaluated the following flags: "blasts?/abnormal lymph?" and "immature granulocytes present" and compared differences in turnaround time between methods. RESULTS: We collected data on 2239 CBC w/ diff Sysmex automated analyzer differential and CellaVision-assisted visual differential from the inpatient hematology-oncology population of a tertiary care medical center. Solely analyzing the first CBC/diff from each unique patient, both flags had a combined sensitivity of 100%, specificity of 50.2%, PPV of 21.7%, and NPV of 100%. The mean turnaround time for the automated differential was 19.5 minutes (SD 35.9 minutes) compared with 66.4 minutes for the CellaVision-assisted visual differential (SD 68.5 minutes; P < 0.001; Figure 1). CONCLUSION: The Sysmex XN-10 abnormal lymphocyte/blast and immature granulocytes flags had excellent sensitivity and acceptable specificity in detecting circulating blasts with shorter turnaround time than the CellaVision-assisted visual differential. Our study suggests that automated differentials performed on Sysmex XN-10 can replace visual differentials as a first-line screening method for blast detection with improved turnaround time in hematology-oncology populations.

Human ehrlichiosis at a tertiary-care academic medical center: Clinical associations and outcomes of transplant patients and patients with hemophagocytic lymphohistiocytosis.

BACKGROUND: Ehrlichiosis is an acute febrile tick-borne disease which can rarely be a trigger for secondary hemophagocytic lymphohistiocytosis (HLH). METHODS: We reviewed our experience with Ehrlichia infections at a tertiary-care academic medical center. RESULTS: Over 10 years, 157 cases of ehrlichiosis were identified. Ten patients (6.4%) had infection with E. ewingii, 7(4.5%) of whom were transplant patients as compared to 3(1.9%) non-transplant patients (p = .035). Transplant patients were more likely to have leukopenia and elevated creatinine compared to immunocompetent patients; length of hospital stay and early mortality were not different between the two groups. Ten patients met the HLH-2004 diagnosis criteria, which could be an underestimation of HLH occurrence as most patients were not completely evaluated for these criteria. We calculated the H-Score to find the probability of HLH; 25 patients scored high making the occurrence rate of HLH at least 16%. Ehrlichia-induced HLH patients (N = 25) had more anemia, thrombocytopenia, elevated creatinine and AST. Moreover, they had a significantly longer hospital stay (median 9 days) compared to patients without HLH (median 4 days) (p = .006). CONCLUSIONS: Ehrlichia-induced HLH is a potential serious complication with relatively high occurrence rate; patients manifest severe disease with end-organ damage requiring longer hospital stay.

Plasmapheresis for Management of Antiphospholipid Syndrome in the Neurosurgical Patient.

BACKGROUND AND IMPORTANCE: Antiphospholipid syndrome (APS) is an autoimmune disorder associated with a hypercoagulable state and increased risk of intraoperative and postoperative thrombosis. Few neurosurgical studies have examined the management of these patients, though the standard of care in most other disciplines involves the use of anticoagulation therapy. However, this is associated with risks such as hemorrhage, thrombosis due to warfarin withdrawal, and is not compatible with operative intervention. CLINICAL PRESENTATION: We report the cases of 2 antiphospholipid positive patients who were on anticoagulant therapy and underwent surgical bypasses and received perioperative management with plasmapheresis. The first was a 44-yr-old woman who presented with worsening vision, recurring headaches, and a known left internal carotid artery aneurysm that was unsuccessfully treated twice via extracranial to intracranial (ECIC) bypass at another institution. Preoperative tests at our institution revealed elevated beta 2 glycoprotein 1 IgA autoantibodies. The second case was a 24-yr-old woman with previously diagnosed APS, who presented for surgical evaluation of moyamoya disease after sustaining recurrent left hemispheric strokes. Both cases were managed with perioperative plasmapheresis to avoid the need for anticoagulation during the perioperative period, and both underwent successful ECIC bypass procedures without perioperative ischemic or hemorrhagic complications. CONCLUSION: Management of neurosurgical patients with APS can be a precarious proposition. We describe the successful use of plasmapheresis and antiplatelet therapy to better manage patients undergoing neurosurgical procedures, specifically ECIC bypass, and feel this approach can be considered in future cases.

Transfusion requirements and 30-day mortality predictors for adult hemophagocytic lymphohistiocytosis.

Hemophagocytic lymphohistiocytosis (HLH) is a rare clinical syndrome characterized by an uncontrolled hyper-inflammatory response. We assessed the transfusion requirements and predictors of 30-day mortality for adult HLH patients. We identified all adult patients with a diagnosis of HLH at a large academic hospital from October 2003 through February 2017. We extracted patients' clinical and laboratory data, including transfusion requirements, from their medical records. One-hundred sixteen patients were identified. Their median age was 48 years (range 18-82); 72(62%) were male. Median duration of hospital stay was 19 days (range 1-89 days). At 30 days from admission, 81(70%) patients were alive. Death was attributed to sepsis in 21 patients, lymphoma in six, bleeding in four, GVHD in one, liver failure in one, metastatic solid tumor in one, and unknown in one. Transfusion requirements at 30 days from admission were as follows: RBC, 86% of patients, median 6 units (range 1-58); platelets, 74% of patients, median 6 units (1-67); plasma, 40% of patients, median 4 units (1-56). Renal failure (OR = 4.39; P = 0.008) and hypofibrinogenemia (OR = 4.07; P = 0.009) correlated with 30-day mortality. The transfusion requirements for adult HLH patients were high. Our study indicated that renal insufficiency and hypofibrinogenemia are predictors of early death in adult HLH.

Heartland Virus and Hemophagocytic Lymphohistiocytosis in Immunocompromised Patient, Missouri, USA.

Heartland virus is a suspected tickborne pathogen in the United States. We describe a case of hemophagocytic lymphohistiocytosis, then death, in an immunosuppressed elderly man in Missouri, USA, who was infected with Heartland virus.

Postoperative Myocardial Injury and Inflammation Is Not Blunted by a Trial of Atorvastatin in Orthopedic Surgery Patients.

BACKGROUND: Orthopedic patients are at risk for adverse postoperative cardiovascular outcomes. QUESTIONS/PURPOSES: This pilot randomized controlled trial (RCT) of atorvastatin vs. placebo in orthopedic surgery patients was performed in order to assess: (1) the prevalence of perioperative myocardial injury; (2) the effect of atorvastatin on perioperative inflammation; and (3) the feasibility of performing a large RCT of statin therapy in orthopedic patients. METHODS: Hip fracture (hip Fx) and total hip and knee replacement (THR and TKR) patients were randomized 1:1 to atorvastatin 40 mg daily vs. placebo, starting preoperatively and continuing until postoperative day (POD) 45. High-sensitivity cardiac troponin I (hs-cTnI), high-sensitivity C-reactive protein (hs-CRP), and interleukin-6 (IL-6) were measured preoperatively and on POD 2. Patients were monitored for adverse events until POD 90. RESULTS: Five hundred fifty-six patients were screened, 22 were recruited (4 hip Fx, 11 THR, 7 TKR), and 2 withdrew. Most (80%) had detectable hs-cTnI (> 1.1 pg/mL) preoperatively. Twenty percent had a perioperative rise in hs-cTnI (≥ 10 pg/mL), which was not blunted by atorvastatin. Hs-CRP rose in 19/20 patients, and IL-6 rose in all patients. However, atorvastatin did not blunt the rise in these inflammatory biomarkers. On POD 2, IL-6 and hs-cTnI levels correlated (ρ = 0.59, p = 0.02). Recruitment was limited by the high prevalence of statin use in the screened population and a high prevalence of exclusions among hip fracture patients. CONCLUSION: Perioperative myocardial injury and inflammation are common in orthopedic patients and do not appear to be reduced in those randomized to atorvastatin. TRIAL REGISTRATION: NCT02197065.

Effect of Genotype-Guided Warfarin Dosing on Clinical Events and Anticoagulation Control Among Patients Undergoing Hip or Knee Arthroplasty: The GIFT Randomized Clinical Trial.

Importance: Warfarin use accounts for more medication-related emergency department visits among older patients than any other drug. Whether genotype-guided warfarin dosing can prevent these adverse events is unknown. Objective: To determine whether genotype-guided dosing improves the safety of warfarin initiation. Design, Setting, and Patients: The randomized clinical Genetic Informatics Trial (GIFT) of Warfarin to Prevent Deep Vein Thrombosis included patients aged 65 years or older initiating warfarin for elective hip or knee arthroplasty and was conducted at 6 US medical centers. Enrollment began in April 2011 and follow-up concluded in October 2016. Interventions: Patients were genotyped for the following polymorphisms: VKORC1-1639G>A, CYP2C9*2, CYP2C9*3, and CYP4F2 V433M. In a 2 × 2 factorial design, patients were randomized to genotype-guided (n = 831) or clinically guided (n = 819) warfarin dosing on days 1 through 11 of therapy and to a target international normalized ratio (INR) of either 1.8 or 2.5. The recommended doses of warfarin were open label, but the patients and clinicians were blinded to study group assignment. Main Outcomes and Measures: The primary end point was the composite of major bleeding, INR of 4 or greater, venous thromboembolism, or death. Patients underwent a screening lower-extremity duplex ultrasound approximately 1 month after arthroplasty. Results: Among 1650 randomized patients (mean age, 72.1 years [SD, 5.4 years]; 63.6% women; 91.0% white), 1597 (96.8%) received at least 1 dose of warfarin therapy and completed the trial (n = 808 in genotype-guided group vs n = 789 in clinically guided group). A total of 87 patients (10.8%) in the genotype-guided group vs 116 patients (14.7%) in the clinically guided warfarin dosing group met at least 1 of the end points (absolute difference, 3.9% [95% CI, 0.7%-7.2%], P = .02; relative rate [RR], 0.73 [95% CI, 0.56-0.95]). The numbers of individual events in the genotype-guided group vs the clinically guided group were 2 vs 8 for major bleeding (RR, 0.24; 95% CI, 0.05-1.15), 56 vs 77 for INR of 4 or greater (RR, 0.71; 95% CI, 0.51-0.99), 33 vs 38 for venous thromboembolism (RR, 0.85; 95% CI, 0.54-1.34), and there were no deaths. Conclusions and Relevance: Among patients undergoing elective hip or knee arthroplasty and treated with perioperative warfarin, genotype-guided warfarin dosing, compared with clinically guided dosing, reduced the combined risk of major bleeding, INR of 4 or greater, venous thromboembolism, or death. Further research is needed to determine the cost-effectiveness of personalized warfarin dosing. Trial Registration: clinicaltrials.gov Identifier: NCT01006733.

Elevated serum ferritin is not specific for hemophagocytic lymphohistiocytosis.

Hemophagocytic lymphohistiocytosis (HLH) is a rare, potentially fatal, syndrome of excessive and ineffective activation of the immune system. The majority of the reported data on HLH is from pediatric patients and lacks specificity. This makes HLH diagnosis challenging especially in adults where HLH is triggered by many conditions and can resemble many disease entities. Elevated ferritin is one of the diagnostic criteria for HLH. We determined the conditions associated with elevated ferritin at our medical center to assess how specific ferritin is for predicting HLH. We retrospectively reviewed all ferritin results >10,000 µg/L in pediatric and adult patients. The most common condition associated with elevated ferritin was hematologic malignancy in adults (25.7%) and HLH in pediatric patients (48.9%). HLH was diagnosed in 14.2% of adults and 48.9% of children with ferritin >10,000 µg/L. Hyperferritinemia occurs in a variety of conditions and is not specific for adult or pediatric HLH. Common causes of elevated ferritin should be considered before entertaining the possibility of HLH, especially in adult patients.