42 The accuracy and clinical implications of point-of-care testing in children

Primary Subject area Nephrology Background Point-of-care testing (POCT) is commonly used at our institution to gather data quickly for sick patients, including electrolytes, glucose, and hemoglobin. Serum electrolytes, hemoglobin, and glucose are the gold standard of testing, but the results often lag POCT by a significant time period. Management decisions are made on the results returned by POCT. Thus, it is imperative to determine the accuracy of POCT at our institution. Objectives Determining whether POCT is an accurate and clinically appropriate method to measure electrolytes, glucose, and hemoglobin compared to standard serum testing. Design/Methods This study retrospectively reviewed 128 consecutive patients either assessed in the emergency department or admitted prior to November 1, 2019 who had both POCT and serum electrolytes (+/- glucose, hemoglobin, and lactate) performed within 4 hours of each other. A sample size of 128 was required to determine a difference of 3 mmol/L in sodium for an effect size of 0.5, with 0.05 level of significance and 80% statistical power. Patient demographics and additional labs drawn within 4 hours of POCT were extracted. Paired t-tests were used to compare values between serum testing and POCT for each patient. Secondary kappa coefficient analyses were performed to look at agreement within clinically-determined normal ranges. POCT was performed on Radiometer ABL835 FLEX analyzers, and serum testing on Beckman Coulter DxC 800 analyzers. Results There were 56 males and 72 females; age range 0.01–17.93 years. There were statistically significant differences between POCT and serum values for all electrolytes and hemoglobin, with POCT over-estimating, but not for glucose (Table 1). Within clinically determined normal ranges, there was substantial agreement between POCT and serum potassium, glucose, and hemoglobin, and fair agreement for sodium and bicarbonate (Table 2). Conclusion Our study highlights the importance of verifying abnormal POCT electrolytes and hemoglobin with serum values. Even when POCT values are normal, clinically significant hyponatremia and hypokalemia may not be detected, and when abnormal, hypernatremia and hyperkalemia may be overestimated. In patients with dysnatremia, if diagnosed with serum sodium and monitored with POCT (or vice versa), there is potential for incorrect diagnosis and/or rate of correction with clinical impact. Thus, when following electrolytes and hemoglobin values in a patient, POCT and serum should not be interchanged, and if there is clinical suspicion for these to be abnormal, verification with serum is warranted. Our study is limited to the specific POCT analyzer used, and behaviour of another analyzer may be different.

Cardiovascular outcomes in systemic sclerosis with abnormal cardiovascular MRI and serum cardiac biomarkers

ObjectivesTo explore the prognostic value of subclinical cardiovascular (CV) imaging measures and serum cardiac biomarkers in systemic sclerosis (SSc) for the development of CV outcomes of primary heart involvement (pHI).MethodsPatients with SSc with no clinical SSc-pHI and no history of heart disease underwent cardiovascular magnetic resonance (CMR) imaging, and measurement of serum high-sensitivity-troponin I (hs-TnI) and N-terminal-pro-brain natriuretic peptide (NT-proBNP). Follow-up clinical and CV outcome data were recorded. CV outcomes were defined as myocarditis, arrhythmia and/or echocardiographic functional impairment including systolic dysfunction and/or diastolic dysfunction.ResultsSeventy-four patients with a median (IQR) age of 57 (49, 63) years, 32% diffuse cutaneous SSc, 39% interstitial lung disease, 30% Scl70+ were followed up for median (IQR) 22 (15, 54) months. Ten patients developed CV outcomes, comprising one patient with myocarditis and systolic dysfunction and nine arrhythmias: three non-sustained ventricular tachycardia and six supraventricular arrhythmias. The probability of CV outcomes was considerably higher in those with NT-proBNP >125 pg/mL versus normal NT-proBNP (X2=4.47, p=0.035). Trend for poorer time-to-event was noted in those with higher extracellular volume (ECV; indicating diffuse fibrosis) and hs-TnI levels versus those with normal values (X2=2.659, p=0.103; X2=2.530, p=0.112, respectively). In a predictive model, NT-proBNP >125 pg/mL associated with CV outcomes (OR=5.335, p=0.040), with a trend observed for ECV >29% (OR=4.347, p=0.073).ConclusionThese data indicate standard serum cardiac biomarkers (notably NT-proBNP) and CMR indices of myocardial fibrosis associate with adverse CV outcomes in SSc. This forms the basis to develop a prognostic model in larger, longitudinal studies.

Biliary Strictures and Cholangiocarcinoma – Untangling a Diagnostic Conundrum

Cholangiocarcinoma is an uncommon and highly aggressive biliary tract malignancy with few manifestations until late disease stages. Diagnosis is currently achieved through a combination of clinical, biochemical, radiological and histological techniques. A number of reported cancer biomarkers have the potential to be incorporated into diagnostic pathways, but all lack sufficient sensitivity and specificity limiting their possible use in screening and early diagnosis. The limitations of standard serum markers such as CA19-9, CA125 and CEA have driven researchers to identify multiple novel biomarkers, yet their clinical translation has been slow with a general requirement for further validation in larger patient cohorts. We review recent advances in the diagnostic pathway for suspected CCA as well as emerging diagnostic biomarkers for early detection, with a particular focus on non-invasive approaches.

Murine Dendritic Cells Grown in Serum-Free Culture Show Potent Therapeutic Activity when Loaded with Novel Th Epitopes in an Orthotopic Model of HER2pos Breast Cancer

Preferred methods for generating mouse dendritic cells (DC) would encompass qualities of consistency, high yield, and potent function. Serum-free culture is also highly desirable, since this is the standard for cell-based therapies used in humans. We report here a serum-free modification of a culture method generating mature, activated DCs from bone marrow precursors. This is achieved through a two-stage culture comprised of 6-day expansion in Flt3 ligand and IL-6 followed by brief differentiation in a medium containing GM-CSF and IL-4, with subsequent activation using TLR ligands ODN1826 and LPS. The serum-free DCs achieve yields and surface phenotype including IL-12p70 secretion similar to standard serum-replete cultures, display a capacity to sensitize in vivo against both MHC class I- and Class II-restricted antigens, and exhibit some aspects of “killer DC” function against tumor cells. We used these DCs to help identify novel CD4pos Th epitopes on the rat ErbB2/HER-2 protein and demonstrated a subset of these as effective immunogens in a DC-based therapeutic model of HER-2pos breast cancer in Balb/c mice, where they induced powerful Th1-polarized immune responses. This method represents a useful way to efficiently produce large numbers of murine dendritic cells with excellent in vivo function well-suited for use in experimental vaccine studies.

Optimization of a human milk–directed quantitative sIgA ELISA method substantiated by mass spectrometry

Immunoglobulins are the primary protective products in human milk and are responsible for transferring maternal pathogen memory to the infant, providing protection by binding to recognized pathogens and inhibiting virulence. To better understand potentially protective/anti-infective compounds in human milk, the establishment of human milk–tailored analytical approaches is crucial, as most contemporary analytical methods have been optimized for plasma or serum. One of the most prominent immunoglobulins in human milk is secretory immunoglobulin A (sIgA), which may be relevant for the protection of breastfed infants from harmful pathogens. Advanced sIgA detection methods can help monitor the immune status and development of the mother-infant dyad. We therefore developed an enzyme-linked immunosorbent assay (ELISA) sIgA method for the quantitative analysis of IgA plus secretory component (SC), validated with sIgA standards and substantiated by mass spectrometry (MS)–based proteomics. A very strong correlation was observed between the MS-detected IgA1 and the human milk–specific sIgA ELISA (r = 0.82). Overall, the MS data indicate that the developed human milk sIgA ELISA does not differentiate between sIgA1 and sIgA2 and is, therefore, a reflection of total sIgA. Furthermore, our MS data and the human milk–derived sIgA ELISA data are better correlated than data derived from a standard serum IgA ELISA kit (relative to MS IgA1 r = 0.82 and r = 0.42, respectively). We therefore propose our human milk–specific sIgA ELISA as an ideal quantitative indicator of total sIgA with advantages over current serum IgA ELISA kits.

THE VALUE OF DIFFERENTIATION OF WEAK FORMS OF D ANTIGEN OF THE ERYTHROCYTE SYSTEM RHESUS IN CLINICAL TRANSFUSIOLOGY AND OBSTETRICS

Summary. The characteristics of variants of antigen D are important because their immunogenicity and, consequently, clinical value depend on them. Objective. To identify weak forms of D antigen of the Rhesus erythrocyte system using available methods, to investigate their frequency and to determine a strategy for interpreting the rhesus status of the individual. Materials and methods. Rhesus affiliation of 3501 blood donors was determined, RhD affiliation of 44 people was specified. The studies were performed in hemagglutination reactions on a plane, test tubes, indirect Coombs’ test, micromethod in gel with MCA anti-D IgM, anti-D IgG, anti-D/DVI IgM/IgG, standard universal reagent antirhesus and standard serum antirhesus. Results and discussion. Dweak was defined 1 % among donors, which is no different from its frequency among Europeans. 40 of the 44 subjects had Dweak and were classified as RhD +, 2 – DVI + — as RhD–, taking into account the world practice of referring an individual with serologically weak D depending on the category of the subject. Conclusions. Due to significant differences in the immune response of individuals with Dweak and Dpartial to D + antigenic stimulus, in-depth examination of their RhD status is appropriate to determine transfusion and obstetric tactics.

Immunoproteomic Analysis Reveals Novel Candidate Antigens for the Diagnosis of Paracoccidioidomycosis Due to Paracoccidioides lutzii

Paracoccidioidomycosis (PCM) is a life-threatening systemic infection caused by the fungal pathogen Paracoccidioides brasiliensis and related species. Whole-genome sequencing and stage-specific proteomic analysis of Paracoccidioides offer the opportunity to profile humoral immune responses against P. lutzii and P. brasiliensis s. str. infection using innovative screening approaches. Here, an immunoproteomic approach was used to identify PCM-associated antigens that elicit immune responses by combining 2-D electrophoresis of P. lutzii and P. brasiliensis proteomes, immunological detection using a gold-standard serum, and mass spectrometry analysis. A total of 16 and 25 highly immunoreactive proteins were identified in P. lutzii and P. brasiliensis, respectively, and 29 were shown to be the novel antigens for Paracoccidioides species, including seven uncharacterized proteins. Among the panel of proteins identified, most are involved in metabolic pathways, carbon metabolism, and biosynthesis of secondary metabolites in both immunoproteomes. Remarkably, six isoforms of the surface-associated enolase in the range of 54 kDa were identified as the major antigens in human PCM due to P. lutzii. These novel immunoproteomes of Paracoccidioides will be employed to develop a sensitive and affordable point-of-care diagnostic assay and an effective vaccine to identify infected hosts and prevent infection and development of human PCM. These findings provide a unique opportunity for the refinement of diagnostic tools of this important neglected systemic mycosis, which is usually associated with poverty.

A Novel Earwax Method to Measure Acute and Chronic Glucose Levels

Diabetes is the fourth cause of death globally. To date, there is not a practical, as well as an accurate sample for reflecting chronic glucose levels. We measured earwax glucose in 37 controls. Participants provided standard serum, glycated hemoglobin (HbA1c) and earwax samples at two time-points, one month apart. The specimens measured baseline fasting glucose, a follow-up postprandial glucose level and a between sample chronic glucose, calculated using the average level on the two occasions. The baseline earwax sample was obtained using a clinical method and the follow-up using a novel self-sampling earwax device. The earwax analytic time was significantly faster using the novel device, in comparison to the clinical use of the syringe. Earwax accurately reflected glucose at both assessments with stronger correlations than HbA1c. Follow-up postprandial concentrations were more significant than their respective fasting baseline concentrations, reflecting differences in fasting and postprandial glycemia and more efficient standardization at follow up. Earwax demonstrated to be more predictable than HbA1c in reflecting systemic fasting, postprandial and long-term glucose levels, and to be less influenced by confounders. Earwax glucose measurements were approximately 60% more predictable than HbA1c in reflecting glycemia over a month. The self-sampling device provided a sample that might accurately reflect chronic glycemia.

A Novel Earwax Method to Measure Acute and Chronic Glucose Levels

Increased chronic glucose is associated with pandemic diseases. To date, there is not a practical, as well as accurate sample for reflecting that level. We measured earwax glucose in 37 controls. They provided standard serum samples, Glycated Haemoglobin (HbA1c) and earwax samples on two time-points, one month a part. The specimens measured baseline fasting glucose, a follow-up postprandial glucose level and a between sample chronic glucose, calculated using the average level on the two occasions. The baseline earwax sample was obtained using a clinical method and the follow-up using a novel self-sampling earwax device. The earwax analytic time was significantly faster using the novel device in comparison to the clinical use of the syringe. Earwax accurately reflected glucose at both assessments with stronger correlations than HbA1c. Follow-up postprandial concentrations were more significant than their respective fasting baseline concentrations, reflecting differences in fasting and postprandial glycaemia and more efficient standardisation at follow up. Earwax demonstrated to be more predictable than HbA1c in reflecting systemic fasting, postprandial and long-term glucose levels and immune by confounders. Earwax glucose was approximately 60% more predictable than HbA1c in reflecting glycaemia over a month. The self-sampling device provided a sample that might accurately reflect chronic glycaemia.