Laboratory features in acute paediatric poisoning with liquid laundry detergent capsules: a seven-year retrospective study in Romania.

INTRODUCTION: The epidemiological and clinical characteristics of acute poisoning with liquid laundry detergent capsules have been comprehensively reported. However, studies of laboratory test results in these exposures are uncommon. This study analyzed the impact of the ingestion of liquid laundry detergent capsules on admission laboratory tests in paediatric patients. METHODS: This retrospective study was conducted in the clinical toxicology unit of a paediatric poison centre between 2015 and 2021. Paediatric patients (less than 18 years of age) who ingested liquid laundry detergent capsules were included. The relationship between the European Association of Poisons Centers and Clinical Toxicologists/European Commission/International Programme on Chemical Safety Poisoning Severity Score and admission laboratory test results was assessed using Fisher's exact test or analysis of variance. RESULTS: A total of 156 patients were included in the study. A considerable proportion of patients presented with leucocytosis, acidosis, hyperlactataemia or base deficit. The median values of white blood cell count (P = 0.042), pH (P = 0.022), and base excess (P = 0.013) were significantly different among the Poisoning Severity Score groups. Hyperlactataemia was strongly associated with the Poisoning Severity Score (P = 0.003). DISCUSSION: Leucocytosis is a non-specific marker of severity following ingestion of liquid laundry detergent capsules. The incidence of metabolic acidosis and hyperlactataemia was higher in this study than in previous reports, but these metabolic features were not related to the severity of exposure. The exact mechanisms of toxicity are not yet known, but the high concentration of non-ionic and anionic surfactants, as well as propylene glycol and ethanol, in the capsule are likely contributing factors. CONCLUSIONS: Pediatric patients who ingest liquid laundry detergent capsules may develop leucocytosis, metabolic acidosis, hyperlactataemia, and a base deficit.

Involvement of the Laboratory Department in MDT Discussion for the Diagnosis of Unexplained Leukocytosis.

BACKGROUND: This paper reports the diagnostic process of a case involving an 86-year-old male patient who was admitted with cough, sputum, and fever, accompanied by persistent leukocytosis. METHODS: Through a multidisciplinary team (MDT) discussion, the laboratory department identified elevated ferritin levels, prompting clinical consideration of potential malignancy. RESULTS: Further investigations confirmed the diagnosis of thyroid cancer with multiple lung metastases. CONCLUSIONS: This case highlights the potential value of ferritin in tumor diagnosis, offering new insights into the etiology of abnormal leukocyte elevation. Additionally, the active involvement of the laboratory department in MDT discussions proves to be crucial for diagnosing challenging cases.

Performance evaluation of the digital morphology analyser Sysmex DI-60 for white blood cell differentials in abnormal samples.

Sysmex DI-60 enumerates and classifies leukocytes. Limited research has evaluated the performance of Sysmex DI-60 in abnormal samples, and most focused on leukopenic samples. We evaluate the efficacy of DI-60 in determining white blood cell (WBC) differentials in normal and abnormal samples in different WBC count. Peripheral blood smears (n = 166) were categorised into normal control and disease groups, and further divided into moderate and severe leucocytosis, mild leucocytosis, normal, mild leukopenia, and moderate and severe leukopenia groups based on WBC count. DI-60 preclassification and verification and manual counting results were assessed using Bland-Altman and Passing-Bablok regression analyses. The Kappa test compared the concordance in the abnormal cell detection between DI-60 and manual counting. DI-60 exhibited notable overall sensitivity and specificity for all cells, except basophils. The correlation between the DI-60 preclassification and manual counting was high for segmented neutrophils, band neutrophils, lymphocytes, and blasts, and improved for all cell classes after verification. The mean difference between DI-60 and manual counting for all cell classes was significantly high in moderate and severe leucocytosis (WBC > 30.0 × 109/L) and moderate and severe leukopenia (WBC < 1.5 × 109/L) groups. For blast cells, immature granulocytes, and atypical lymphocytes, the DI-60 verification results were similar to the manual counting results. Plasma cells showed poor agreement. In conclusion, DI-60 demonstrates consistent and reliable analysis of WBC differentials within the range of 1.5-30.0 × 109. Manual counting was indispensable in examining moderate and severe leucocytosis samples, moderate and severe leukopenia samples, and in enumerating of monocytes and plasma cells.

Clinical outcomes in a murine model after envenoming by the Amazonian scorpions Tityus strandi and Tityus dinizi.

The Brazilian Amazon is home to a rich fauna of scorpion species of medical importance, some of them still poorly characterized regarding their biological actions and range of clinical symptoms after envenoming. The Amazonian scorpion species Tityus strandi and Tityus dinizi constitute some of the scorpions in this group, with few studies in the literature regarding their systemic repercussions. In the present study, we characterized the clinical, inflammatory, and histopathological manifestations of T. strandi and T. dinizi envenoming in a murine model using Balb/c mice. The results show a robust clinical response based on clinical score, hyperglycemia, leukocytosis, increased cytokines, and histopathological changes in the kidneys and lungs. Tityus strandi envenomed mice presented more prominent clinical manifestations when compared to Tityus dinizi, pointing to the relevance of this species in the medical scenario, with both species inducing hyperglycemia, leukocytosis, increased cytokine production in the peritoneal lavage, increased inflammatory infiltrate in the lungs, and acute tubular necrosis after T. strandi envenoming. The results presented in this research can help to understand the systemic manifestations of scorpion accidents in humans caused by the target species of the study and point out therapeutic strategies in cases of scorpionism in remote regions of the Amazon.

Paraneoplastic leukocytosis secondary to carcinosarcoma: a report of two cases and literature review.

BACKGROUND: Neutrophilia is an increase in the number of neutrophils over 7.5×103/µL. An increase in leukocytes over 50×103/µL is called a leukemoid reaction; and when it is associated with a solid tumor, it is considered a paraneoplastic syndrome called paraneoplastic leukemoid reaction (PLR). It is a very rare clinical condition and it is very unusual for it to be associated with carcinosarcoma. We present two cases of a leukemoid reaction observed in the Medical Oncology Department of the University Hospital of Salamanca between May and September 2023. The main objectives of our article are to describe the unusual appearance of paraneoplastic leukocytosis at the diagnosis of carcinosarcoma carcinosarcoma, explain in a detailed way its diagnostic procedure and to show the poor prognosis to which it is associated. CASE DESCRIPTION: In our presentation, we describe two similar cases: first of all, a 60-year-old woman without relevant medical history. She was referred by her primary physician to the Department of Internal Medicine in August 2023 with asthenia, lumbar pain, and weight loss of 12 kg of 3 months of evolution. The physical examination revealed a palpable hypogastric mass. An abdominal, pelvic, and thoracic computed tomography (CT) scan revealed a heterogenous solid mass with necrotic areas originating in the uterus. The anatomopathological diagnosis was carcinosarcoma. The patient showed a progressive worsening in her renal function associated with hyperviscosity secondary to hyperleukocytosis caused by 170×103/µL neutrophils. In the second case we describe the diagnosis of a PLR secondary to a kidney carcinosarcoma. When the patient started chemotherapy, he presented 55.08×103/µL leukocytes, 53.16×103/µL neutrophils. Eight days after receiving chemotherapy, the patient was admitted as an emergency with oligoanuria and decreased consciousness. He presented creatinine 6.25 mg/dL, phosphate 12.4 mg/dL, leukocytes 1.05×103/µL, and neutrophils 0.71×103/µL. The clinical diagnosis was acute exacerbation of multifactorial mixed (renal and prerenal) chronic kidney disease associated with tumor lysis syndrome and grade 3 neutropenia. The patient presented a poor evolution, dying after 2 months. CONCLUSIONS: PLR is a severe paraneoplastic syndrome associated with different types of solid tumors. Its appearance at the time of diagnosis of a tumor implies a poor vital prognosis.

Presumed pseudo-Pelger-Huët anomaly and basophilia secondary to chronic lymphocytic leukemia in a dog.

A 10-year-old neutered male Maltese dog was presented for an investigation of lymphocytosis. The dog was up-to-date on vaccinations and deworming. Physical examination did not reveal any significant abnormalities. A complete blood cell count (CBC) showed mild leukocytosis with moderate lymphocytosis, basophilia, and moderate neutropenia, but no significant left shift or toxic change. Serum biochemistry and urinalysis were unremarkable. All performed tests for infectious agents common in this geographical region were negative. No significant abnormalities were found on abdominal ultrasound examination. Multiparametric flow cytometry of peripheral blood showed a CD8+ T-cell lymphocytosis, and PCR for antigen receptor rearrangement revealed a clonal expansion of the T-cell receptor gamma chain genes. A clinical diagnosis of chronic lymphocytic leukemia (CLL) was made, and follow-up was recommended. On Day 48 post-presentation, the CBC showed mild non-regenerative anemia (NRA), moderate leucocytosis due to moderate to marked lymphocytosis, basophilia, and a marked increase in hyposegmented neutrophils with mild toxic change in the absence of neutrophilia or neutropenia. Treatment with chlorambucil and prednisolone was initiated. On Days 87 and 197 post-presentation, the CBC showed mild NRA, with progressively decreasing numbers of hyposegmented neutrophils. The dog remained without clinical signs. Basophilia and probable pseudo-Pelger-Huët anomaly were possibly secondary to CLL. To the authors' knowledge, this is the first report of these two hematologic conditions secondary to CLL in dogs. Recognition of a pseudo-Pelger-Huët anomaly is clinically relevant to avoid misinterpretation as a marked left shift due to severe inflammation and prevent unnecessary urgent therapeutic actions.

The influence of hematological profiles on the transfusion management and mortality risk of mothers presenting to the obstetric unit of a South African tertiary medical facility.

BACKGROUND: Laboratory results are frequently abnormal in pregnant mothers. Abnormalities usually relate to pregnancy or associated complications. Hematological abnormalities and age in pregnancy may increase the likelihood for transfusion and mortality. STUDY DESIGN AND METHODS: Hematological profiles and transfusion history of pregnant mothers presenting to a tertiary hospital, were evaluated over 2 years. Age, anemia, leukocytosis and thrombocytopenia were assessed for transfusion likelihood. Iron deficiency and coagulation were assessed in transfused patients. Anemia, leukocytosis, thrombocytopenia, human immunodeficiency virus (HIV) and transfusion were assessed for mortality likelihood. RESULTS: There were 12,889 pregnant mothers included. Mothers <19-years-old had the highest prevalence of anemia (31.5%) and proportion of transfusions (19%). The transfusion likelihood was increased in mothers with anemia (odds ratios [OR] = 6.41; confidence intervals at 95% [95% CI] 5.46-7.71), leukocytosis (OR = 2.35; 95% CI 2.00-2.76) or thrombocytopenia (OR = 2.71; 95% CI 2.21-3.33). Mothers with prolonged prothrombin times received twice as many blood products as their normal counterparts (p = .03) and those with iron deficiency anemia five times more blood products (p < .001). Increased likelihood for mortality was seen in patients with anemia (OR = 4.15, 95% CI 2.03-8.49), leukocytosis (OR = 2.68; 95% CI 1.19-6.04) and those receiving blood transfusion (OR = 3.6, 95% CI 1.75-7.47). DISCUSSION: Adolescence, anemia, leukocytosis and thrombocytopenia expose mothers to a high risk for transfusion and/or mortality. These risk factors should promptly trigger management and referral of patients. Presenting hematological profiles are strong predictors of maternal outcome and transfusion risk.

First-in-Class Humanized Antibody against Alternatively Spliced Tissue Factor Augments Anti-Metastatic Efficacy of Chemotherapy in a Preclinical Model of Pancreatic Ductal Adenocarcinoma.

Alternatively spliced tissue factor (asTF) promotes the progression of pancreatic ductal adenocarcinoma (PDAC) by activating ß1-integrins on PDAC cell surfaces. hRabMab1, a first-in-class humanized inhibitory anti-asTF antibody we recently developed, can suppress PDAC primary tumor growth as a single agent. Whether hRabMab1 has the potential to suppress metastases in PDAC is unknown. Following in vivo screening of three asTF-proficient human PDAC cell lines, we chose to make use of KRAS G12V-mutant human PDAC cell line PaCa-44, which yields aggressive primary orthotopic tumors with spontaneous spread to PDAC-relevant anatomical sites, along with concomitant severe leukocytosis. The experimental design featured orthotopic tumors formed by luciferase labeled PaCa-44 cells; administration of hRabMab1 alone or in combination with gemcitabine/paclitaxel (gem/PTX); and the assessment of the treatment outcomes on the primary tumor tissue as well as systemic spread. When administered alone, hRabMab1 exhibited poor penetration of tumor tissue; however, hRabMab1 was abundant in tumor tissue when co-administered with gem/PTX, which resulted in a significant decrease in tumor cell proliferation; leukocyte infiltration; and neovascularization. Gem/PTX alone reduced primary tumor volume, but not metastatic spread; only the combination of hRabMab1 and gem/PTX significantly reduced metastatic spread. RNA-seq analysis of primary tumors showed that the addition of hRabMab1 to gem/PTX enhanced the downregulation of tubulin binding and microtubule motor activity. In the liver, hRabMab1 reduced liver metastasis as a single agent. Only the combination of hRabMab1 and gem/PTX eliminated tumor cell-induced leukocytosis. We here demonstrate for the first time that hRabMab1 may help suppress metastasis in PDAC. hRabMab1's ability to improve the efficacy of chemotherapy is significant and warrants further investigation.

Validation of Thermal Imaging and the ALT-70 Prediction Model to Differentiate Cellulitis From Pseudocellulitis.

Importance: Cellulitis is misdiagnosed in up to 30% of cases due to mimic conditions termed pseudocellulitis. The resulting overuse of antibiotics is a threat to patient safety and public health. Surface thermal imaging and the ALT-70 (asymmetry, leukocytosis, tachycardia, and age ≥70 years) prediction model have been proposed as tools to help differentiate cellulitis from pseudocellulitis. Objectives: To validate differences in skin surface temperatures between patients with cellulitis and patients with pseudocellulitis, assess the optimal temperature measure and cut point for differentiating cellulitis from pseudocellulitis, and compare the performance of skin surface temperature and the ALT-70 prediction model in differentiating cellulitis from pseudocellulitis. Design, Setting, and Participants: This prospective diagnostic validation study was conducted among patients who presented to the emergency department with acute dermatologic lower extremity symptoms from October 11, 2018, through March 11, 2020. Statistical analysis was performed from July 2020 to March 2021 with additional work conducted in September 2023. Main Outcomes and Measures: Temperature measures for affected and unaffected skin were obtained. Cellulitis vs pseudocellulitis was assessed by a 6-physician, independent consensus review. Differences in temperature measures were compared using the t test. Logistic regression was used to identify the temperature measure and associated cut point with the optimal performance for discriminating between cellulitis and pseudocellulitis. Diagnostic performance characteristics for the ALT-70 prediction model, surface skin temperature, and both combined were also assessed. Results: The final sample included 204 participants (mean [SD] age, 56.6 [16.5] years; 121 men [59.3%]), 92 (45.1%) of whom had a consensus diagnosis of cellulitis. There were statistically significant differences in all skin surface temperature measures (mean temperature, maximum temperature, and gradients) between cellulitis and pseudocellulitis. The maximum temperature of the affected limb for patients with cellulitis was 33.2 °C compared with 31.2 °C for those with pseudocellulitis (difference, 2.0 °C [95% CI, 1.3-2.7 °C]; P < .001). The maximum temperature was the optimal temperature measure with a cut point of 31.2 °C in the affected skin, yielding a mean (SD) negative predictive value of 93.5% (4.7%) and a sensitivity of 96.8% (2.3%). The sensitivity of all 3 measures remained above 90%, while specificity varied considerably (ALT-70, 22.0% [95% CI, 15.8%-28.1%]; maximum temperature of the affected limb, 38.4% [95% CI, 31.7%-45.1%]; combination measure, 53.9% [95% CI, 46.5%-61.2%]). Conclusions and Relevance: In this large diagnostic validation study, significant differences in skin surface temperature measures were observed between cases of cellulitis and cases of pseudocellulitis. Thermal imaging and the ALT-70 both demonstrated high sensitivity, but specificity was improved by combining the 2 measures. These findings support the potential of thermal imaging, alone or in combination with the ALT-70 prediction model, as a diagnostic adjunct that may reduce overdiagnosis of cellulitis.

A Predictive Algorithm for Discriminating Myeloid Malignancies and Leukemoid Reactions.

BACKGROUND: Adults presenting with a neutrophil-predominant leukocytosis (white cell count >50,000/µL) often necessitate urgent medical management. These patients are diagnosed with either acute presentations of chronic myeloid malignancies or leukemoid reactions, yet accurate models to distinguish between these entities do not exist. We used demographic and lab data to build a machine learning model capable of discriminating between these diagnoses. METHODS: The medical record at a tertiary care medical center was queried to identify adults with instances of white counts greater than 50,000/µL and >50% neutrophils from 2000 to 2021. For each patient, a full set of demographic and lab values were extracted at the time of their first presentation with a white count >50,000/µL. We generated a series of models in which the parameters most predictive of myeloid malignancies were identified, and a supervised machine learning approach was applied to the dataset. RESULTS: Our best model-using a support vector machine algorithm-produced a sensitivity of 96% and a specificity of 95.9% (area under the curve = 0.982) for identifying myeloid malignancies. We also identified a clinically meaningful and significant disparity in outcomes based on diagnosis-a 6-fold increase in 12-month mortality in those diagnosed with leukemoid reactions. CONCLUSIONS: These findings need to be validated but fill an unmet need for timely and accurate diagnosis in the setting of profound, neutrophil-predominant leukocytosis and support the use of predictive models as a means to improve patient outcomes.

Evaluation of hematological changes and immune response biomarkers as a prognostic factor in critical patients with COVID-19.

COVID-19 disease has been a challenge for health systems worldwide due to its high transmissibility, morbidity, and mortality. Severe COVID-19 is associated with an imbalance in the immune response, resulting in a cytokine storm and a hyperinflammation state. While hematological parameters correlate with prognosis in COVID patients, their predictive value has not been evaluated specifically among those severely ill. Therefore, we aim to evaluate the role of hematological and immune response biomarkers as a prognostic factor in critically ill patients with COVID-19 admitted to the intensive care unit. From May 2020 to July 2021, a retrospective cohort study was conducted in a reference hospital in Manaus, which belongs to the Brazilian public health system. This study was carried out as single-center research. Clinical and laboratory parameters were analyzed to evaluate the association with mortality. We also evaluated the role of neutrophil-to-lymphocyte ratio (NLR), lymphocyte-to-monocyte ratio (LMR), platelet-to-lymphocyte ratio (PLR), and C-reactive protein-to-lymphocyte ratio (CLR). We gathered information from medical records, as well as from prescriptions and forms authorizing the use of antimicrobial medications. During the study period, 177 patients were included, with a mean age of 62.58 ± 14.39 years. The overall mortality rate was 61.6%. Age, mechanical ventilation (MV) requirement, leukocytosis, neutrophilia, high c-reactive protein level, NLR, and CLR showed a statistically significant association with mortality in the univariate analysis. In the multivariate logistic regression analysis, only MV (OR 35.687, 95% CI: 11.084-114.898, p< 0.001) and NLR (OR 1.026, 95% CI: 1.003-1.050, p = 0.028) remained statistically associated with the outcome of death (AUC = 0.8096). While the need for mechanical ventilation is a parameter observed throughout the hospital stay, the initial NLR can be a primary risk stratification tool to establish priorities and timely clinical intervention in patients with severe COVID-19 admitted to the ICU.

Exposure to BTEX is associated with cardiovascular disease, dyslipidemia and leukocytosis in national US population.

BACKGROUND: Comprehensive research on the effects of individual benzene, toluene, ethylbenzene, and xylenes (BTEX) and their mixture measured in blood samples, on cardiovascular diseases (CVD) and related risk factors among the general population is limited. OBJECTIVES: To investigate the effects of blood individual and mixed BTEX on total CVD and its subtypes, lipid profiles, and white blood cell (WBC) count. METHODS: Survey-weighted multivariate logistic regression was used to examine the associations between blood individual and mixed BTEX with CVD and its subtypes in 17,007 participants from NHANES 1999-2018. The combined effect of BTEX mixture on CVD was estimated using weighted quantile sum modeling and quantile g-computation. Weighted multivariate linear regression assessed the effects of BTEX on lipid profiles and WBC, including its five-part differential count. RESULTS: In comparison to the reference quartile of BTEX mixture, individuals in the highest quartile had a significantly increased adjusted odds ratio of CVD risk (1.64, 95 % CI: 1.23 to 2.19, P for trend = 0.008). Positive associations were observed for benzene, toluene, ethylbenzene, and m-/p-xylene, demonstrating a monotonically increasing exposure-response relationship. Mixed BTEX was associated with congestive heart failure (CHF), angina pectoris, and heart attack. Individual benzene, toluene, and ethylbenzene were associated with CHF, while toluene, ethylbenzene, and all xylene isomers were linked to angina pectoris. Benzene, toluene, and o-xylene were associated with heart attack. Both mixed and individual BTEX showed positive associations with triglycerides, cholesterol, low-density lipoprotein, and WBC, including its five-part differential count, but a negative relationship with high-density lipoprotein. Subgroup analyses identified modifying effects of smoking, drinking, exercise, BMI, hypertension, and diabetes on the associations between specific toxicants and CVD risk. CONCLUSIONS: Exposure to BTEX was associated with cardiovascular diseases and cardiovascular risk factors. These findings emphasize the importance of considering blood BTEX levels when assessing cardiovascular health risks.

Case 322: Pyothorax-associated Lymphoma.

HISTORY: An 81-year-old man living in South Korea was referred to the pulmonology clinic because of abnormal findings at routine surveillance CT. His past medical history included right radical nephroureterectomy for ureteral cancer in 2016, transurethral resection of a bladder tumor in 2015, and tuberculous pleurisy in his third decade of life that was complicated by a chronic calcified empyema. He had been doing well clinically until 6 months prior, when he presented to an outside hospital with progressive right-sided chest pain and dyspnea and was found to have active tuberculosis. During that hospitalization, he underwent chest CT and CT-guided biopsy of an incidentally found thoracic lesion, which revealed chronic active inflammation. His symptoms improved after initiation of antituberculous medication, and he was discharged home to complete treatment. Because of interval growth of this lesion noted on a subsequent surveillance CT scan, he was referred to pulmonology for further evaluation. Laboratory tests obtained during his visit revealed mild leukocytosis (1258 cells × 109/L; normal range, 4000-10 000 cells × 109/L) with neutrophilic predominance (82% neutrophils; normal range, 50%-75% neutrophils), and a mildly elevated C-reactive protein level (3.17 mg/dL; normal range, 0-0.5 mg/dL). A sputum culture was negative for tuberculosis. The patient reported mild chest discomfort and dyspnea. Liver MRI was performed to further evaluate an abnormal lesion seen at CT. Given the patient's recent nonspecific biopsy results and tuberculosis treatment, no further work-up was pursued. Contrast-enhanced chest CT was performed 6 months later because the patient developed worsening chest pain and dyspnea. He remained afebrile, with persistent leukocytosis (1485 cells × 109/L) and an elevated C-reactive protein level (3.56 mg/dL). On the basis of the imaging findings, repeat CT-guided biopsy and PET/CT were performed, thereby enabling confirmation of the diagnosis, and appropriate treatment was initiated.

The pathogenesis of cancer-associated thrombosis.

Patients with cancer have a higher risk of venous thromboembolism (VTE), including deep vein thrombosis (DVT) and pulmonary embolism (PE), compared to the general population. Cancer-associated thrombosis (CAT) is a thrombotic event that occurs as a complication of cancer or cancer therapy. Major factors determining VTE risk in cancer patients include not only treatment history and patient characteristics, but also cancer type and site. Cancer types can be broadly divided into three groups based on VTE risk: high risk (pancreatic, ovarian, brain, stomach, gynecologic, and hematologic), intermediate risk (colon and lung), and low risk (breast and prostate). This implies that the mechanism of VTE differs between cancer types and that specific VTE pathways may exist for different cancer types. This review summarizes the specific pathways that contribute to VTE in cancer patients, with a particular focus on leukocytosis, neutrophil extracellular traps (NETs), tissue factor (TF), thrombocytosis, podoplanin (PDPN), plasminogen activator inhibitor-1 (PAI-1), the intrinsic coagulation pathway, and von Willebrand factor (VWF).

Predicting Serious Bacterial Infections Among Hypothermic Infants in the Emergency Department.

BACKGROUND: There is insufficient evidence to guide the initial evaluation of hypothermic infants. We aimed to evaluate risk factors for serious bacterial infections (SBI) among hypothermic infants presenting to the emergency department (ED). METHODS: We conducted a multicenter case-control study among hypothermic (rectal temperature <36.5°C) infants ≤90 days presenting to the ED who had a blood culture collected. Our outcome was SBI (bacteremia, bacterial meningitis, and/or urinary tract infection). We performed 1:2 matching. Historical, physical examination and laboratory covariables were determined based on the literature review from febrile and hypothermic infants and used logistic regression to identify candidate risk factors. RESULTS: Among 934 included infants, 57 (6.1%) had an SBI. In univariable analyses, the following were associated with SBI: age > 21 days, fever at home or in the ED, leukocytosis, elevated absolute neutrophil count, thrombocytosis, and abnormal urinalysis. Prematurity, respiratory distress, and hypothermia at home were negatively associated with SBI. The full multivariable model exhibited a c-index of 0.91 (95% confidence interval: 0.88-0.94). One variable (abnormal urinalysis) was selected for a reduced model, which had a c-index of 0.82 (95% confidence interval: 0.75-0.89). In a sensitivity analysis among hypothermic infants without fever (n = 22 with SBI among 116 infants), leukocytosis, absolute neutrophil count, and abnormal urinalysis were associated with SBI. CONCLUSIONS: Historical, examination, and laboratory data show potential as variables for risk stratification of hypothermic infants with concern for SBI. Larger studies are needed to definitively risk stratify this cohort, particularly for invasive bacterial infections.