Detection of SARS-CoV-2 IgG Targeting Nucleocapsid or Spike Protein by Four High-Throughput Immunoassays Authorized for Emergency Use.

A total of 1,200 serum samples that were tested for SARS-CoV-2 IgG antibody using the Abbott Architect immunoassay targeting the nucleocapsid protein were run in 3 SARS-CoV-2 IgG immunoassays targeting spike proteins (DiaSorin Liaison, Ortho Vitros, and Euroimmun). Consensus-positive and consensus-negative interpretations were defined as qualitative agreement in at least 3 of the 4 assays. Agreement of the 4 individual assays with a consensus-negative interpretation (n = 610) ranged from 96.7% to 100%, and agreement with a consensus-positive interpretation (n = 584) ranged from 94.3% to 100%. Laboratory-developed inhibition assays were utilized to evaluate 49 consensus-negative samples that were positive in only one assay; true-positive reactivity was confirmed in only 2 of these 49 (4%) samples. These findings demonstrate very high levels of agreement among 4 SARS-CoV-2 IgG assays authorized for emergency use, regardless of antigen target or assay format. Although false-positive reactivity was identified, its occurrence was rare (no more than 1.7% of samples for a given assay).

Multilaboratory Comparison of Pneumococcal Multiplex Immunoassays Used in Immunosurveillance of Streptococcus pneumoniae across Europe.

Surveillance studies are required to estimate the impact of pneumococcal vaccination in both children and the elderly across Europe. The World Health Organization (WHO) recommends use of enzyme immunoassays (EIAs) as standard methods for immune surveillance of pneumococcal antibodies. However, as levels of antibodies to multiple serotypes are monitored in thousands of samples, a need for a less laborious and more flexible method has evolved. Fluorescent-bead-based multiplex immunoassays (MIAs) are suitable for this purpose. An increasing number of public health and diagnostic laboratories use MIAs, although the method is not standardized and no international quality assessment scheme exists. The EU Pneumo Multiplex Assay Consortium was initiated in 2013 to advance harmonization of MIAs and to create an international quality assessment scheme. In a multilaboratory comparison organized by the consortium, agreement among nine laboratories that used their own optimized MIA was assessed on a panel of 15 reference sera for 13 pneumococcal serotypes with the new WHO standard 007sp. Agreement was assessed in terms of assay accuracy, reproducibility, repeatability, precision, and bias. The results indicate that the evaluated MIAs are robust and reproducible for measurement of vaccine-induced antibody responses. However, some serotype-specific variability in the results was observed in comparisons of polysaccharides from different sources and of different conjugation methods, especially for serotype 4. On the basis of the results, the consortium has contributed to the harmonization of MIA protocols to improve reliability of immune surveillance of Streptococcus pneumoniaeIMPORTANCE Serology of Streptococcus pneumoniae is challenging due to existence of multiple clinically relevant serotypes and the introduction of multivalent vaccines in national immunization programs. Multiplex immunoassays (MIAs) are applied as high-throughput cost-effective methods for serosurveillance, and yet laboratories use their own protocols. The aims of this study were to assess the agreement of results generated by MIAs in different laboratories within the EU Pneumo Multiplex Assay Consortium, to analyze factors contributing to differences in outcome, and to create a harmonized protocol. The study demonstrated good agreement of results of MIAs performed by laboratories using controlled assays for determination of levels of vaccine-induced pneumococcal antibodies. The EU Pneumo Multiplex Assay Consortium is open to everyone working in public health services, and it aims to facilitate efforts by participants to run and maintain a cost-effective, reproducible, high-quality MIA platform.

Altering polymerization temperature of antibiotic-laden cement can increase porosity and subsequent antibiotic elution.

PURPOSE: To examine the role of polymerization temperature on the cement porosity and antibiotic elution to optimize antibiotic release from antibiotic-laden cement (ABLC). METHODS: Elution profiles of vancomycin and tobramycin from ABLC discs prepared with low- and high-dose antibiotic dosages, cured at 8, 21, and 37 °C, and placed in phosphate buffered saline (PBS) at 37 °C were examined. Samples were collected at one, four, eight, 24, 72, 168, 336, and 1008 hours to calculate the quantity of antibiotic eluted. Porosity was determined by MicroCT analysis. RESULTS: ABLC porosity and antibiotic elution were increased up to five times the amount eluted from room temperature discs (p < 0.05). Low-dose ABLC group saw decreased but similar porosity at 8 °C and 21 °C compared to cement cured at 37 °C (p < 0.001). High-dose ABLC group porosities were all significantly different (p < 0.02). CONCLUSIONS: Altering the polymerization temperature of ABLC led to more porous constructs yielding increased antibiotic elution.

Assessment of vertebral wedge strength using cancellous textural properties derived from digital tomosynthesis and density properties from dual energy X-ray absorptiometry and high resolution computed tomography.

The purpose of this study was to examine the potential of digital tomosynthesis (DTS) derived cancellous bone textural measures to predict vertebral strength under conditions simulating a wedge fracture. 40 vertebral bodies (T6, T8, T11, and L3 levels) from 5 male and 5 female cadaveric donors were utilized. The specimens were scanned using dual energy X-ray absorptiometry (DXA) and high resolution computed tomography (HRCT) to obtain measures of bone mineral density (BMD) and content (BMC), and DTS to obtain measures of bone texture. Using a custom loading apparatus designed to deliver a nonuniform displacement resulting in a wedge deformity similar to those observed clinically, the specimens were loaded to fracture and their fracture strength was recorded. Mixed model regressions were used to determine the associations between wedge strength and DTS derived textural variables, alone and in the presence of BMD or BMC information. DTS derived fractal, lacunarity and mean intercept length variables correlated with wedge strength, and individually explained up to 53% variability. DTS derived textural variables, notably fractal dimension and lacunarity, contributed to multiple regression models of wedge strength independently from BMC and BMD. The model from a scan orientation transverse to the spine axis and in the anterior-posterior view resulted in highest explanatory capability (R2adj = 0.91), with a scan orientation parallel to the spine axis and in the lateral view offering an alternative (R2adj = 0.88). In conclusion, DTS can be used to examine cancellous texture relevant to vertebral wedge strength, and potentially complement BMD in assessment of vertebral fracture risk.

Erratum: Screening for disruptive behaviour problems in preschool children in primary health care settings.

[This corrects the article DOI: 10.1093/pch/pxx128.]

Screening for Disruptive Behaviour Problems in Preschool Children in Primary Health Care Settings.

Disruptive behaviour problems in preschool children are significant risk factors for, and potential components of, neurodevelopmental and mental health disorders. Some non-compliance, temper tantrums and aggression between two and five years of age are normal and transient. However, problematic levels of disruptive behaviour, specifically when accompanied by functional impairment and/or significant distress, should be identified because early intervention can improve outcome trajectories. This position statement provides an approach to early identification using clinical screening at periodic health examinations, followed by a systematic mental health examination that includes standardized measures. The practitioner should consider a range of environmental, developmental, family and parent-child relationship factors to evaluate the clinical significance of disruptive behaviours. Options within a management plan include regular monitoring accompanied by health guidance and parenting advice, referral to parent behaviour training as a core evidence-based intervention, and referral to specialty care for preschool children with significant disruptive behaviours, developmental or mental health comorbidities, or who are not responding to first-line interventions.

Elimination of falsely reactive results in a commercially-available West Nile virus IgM capture enzyme-linked immunosorbent assay by heterophilic antibody blocking reagents.

All sera initially reactive in the Focus Diagnostics West Nile virus IgM capture enzyme-linked immunosorbent assay (WNV IgM ELISA) must be retested with background subtraction to identify falsely-reactive (FR) samples due to antibodies that bind to immunoglobulins of other animal species (heterophilic antibodies). In some settings, such as pre-transplant testing of organ donors, the reporting delay associated with retesting can have an adverse impact on donor procurement and organ placement. We sought to determine if inclusion of heterophilic antibody blockers in assay conjugate could eliminate the nonspecific reactivity of FR samples. Of 6 blocking reagents evaluated using a well-characterized FR sample, immunoglobulin inhibiting reagent from Bioreclamation (IIR) and blocker from Fitzgerald Industries (BFI) were superior in their ability to inhibit false reactivity; these 2 blockers were then used to evaluate 20 additional FR and 21 truly-reactive (TR) samples. Both blockers eliminated the reactivity of 20/21 FR samples, whereas all 21 TR samples remained reactive; further, all 13 truly non-reactive (NR) samples evaluated remained non-reactive when using blocker-containing conjugate. A subset of 22 samples were tested in parallel using the initial lot and a second lot of IIR and BFI; with one exception, all samples showed the same qualitative result using both lots of a given blocker. These findings demonstrate that modification of the Focus WNV IgM screening ELISA to include heterophilic antibody blocker IIR or BFI in assay conjugate eliminates the reactivity of most FR samples, markedly reducing the number of samples requiring further testing by background subtraction.

Screening for disruptive behaviour problems in preschool children in primary health care settings.

Disruptive behaviour problems in preschool children are significant risk factors for, and potential components of, neurodevelopmental and mental health disorders. Some noncompliance, temper tantrums and aggression between 2 and 5 years of age are normal and transient. However, problematic levels of disruptive behaviour, specifically when accompanied by functional impairment and/or significant distress, should be identified because early intervention can improve outcome trajectories. This position statement provides an approach to early identification using clinical screening at periodic health examinations, followed by a systematic mental health examination that includes standardized measures. The practitioner should consider a range of environmental, developmental, family and parent-child relationship factors to evaluate the clinical significance of disruptive behaviours. Options within a management plan include regular monitoring, accompanied by health guidance and parenting advice, referral to parent behaviour training as a core evidence-based intervention, and referral to specialty care for preschool children with significant disruptive behaviours, developmental or mental health comorbidities, or who are not responding to first-line interventions.

Evaluation of Commercial Assays for Single-Point Diagnosis of Pertussis in the US.

BACKGROUND: Pertussis serodiagnosis is increasingly being used in the United States despite the lack of a US Food and Drug Administration-approved, commercially available assay. To better understand the utility of these assays in diagnosing pertussis, serology assays were evaluated for analytical parameters and clinical accuracy. METHODS: Forty-three antigen-antibody combinations were evaluated for single-point diagnosis of pertussis. Serum panels included sera from laboratory-confirmed cases, an international reference standard, and healthy donors. Phase I panel (n = 20) of sera was used to assess precision, linearity, and accuracy; Phase II panel (n = 226) followed with positive percent agreement (PPA) and negative percent agreement (NPA) estimates. Analytical analyses included coefficients of variation (CV) and concordance correlation coefficients (rc). RESULTS: Intra-analyst variability was found to be relatively low among samples per assay, with only 6% (78 of 1240) having CV >20%, primarily with the highly concentrated immunoglobulin (Ig)G anti-pertussis toxin (PT) specimens and IgM assays. The rc measurements to assess linearity ranged between 0.282 and 0.994, 0.332 and 0.999, and -0.056 and 0.482 for IgA, IgG, and IgM, respectively. Analytical accuracy for calibrated IgG anti-PT assays was 86%-115%. The PPA and NPA varied greatly for all assays; PPA/NPA ranges for IgA, IgG, and IgM assays, with culture and/or polymerase chain reaction positivity as control, were 29-90/13-100, 26-96/27-100, and 0-73/42-100, respectively. In IgG assays, mixing filamentous hemagglutinin antigen with PT increased PPA but decreased NPA. CONCLUSIONS: Seroassays varied substantially under both analytical and clinical parameters; however, those that were calibrated to a reference standard were highly accurate. Our findings support incorporation of calibrated pertussis seroassays to the pertussis case definition for improved diagnosis and surveillance.

Comparison of Enzyme Immunoassays for Detection of Antibodies to Hepatitis D Virus in Serum.

Serology remains critical for diagnosing hepatitis D virus (HDV) infection, which affects 15 to 20 million people worldwide, but the literature on characterizing commercial enzyme immunoassays (EIAs) dates back to 15 years ago. We evaluated 2 commercial EIAs currently available for detecting anti-HDV antibodies. The DiaSorin assay demonstrated 100% sensitivity and specificity. Using a modified cutoff value, the Cusabio assay demonstrated a sensitivity of 81.3% and specificity of 90.9%. Our data show that recently developed EIAs are reliable for anti-HDV antibody detection.

The Ottawa Self-Injury Inventory: Evaluation of an assessment measure of nonsuicidal self-injury in an inpatient sample of adolescents.

BACKGROUND: The Ottawa Self-Injury Inventory (OSI) is a self-report measure that offers a comprehensive assessment of nonsuicidal self-injury (NSSI), including measurement of its functions and addictive features. In a preliminary investigation of self injuring college students who completed the OSI, exploratory analysis revealed four function factors (Internal Emotion Regulation, Social Influence, External Emotion Regulation and Sensation Seeking) and a single Addictive Features factor. Rates of NSSI are particularly high in inpatient psychiatry youth. The OSI can assistin both standardizing assessment regarding functions and potential addictive features and aid case formulation leading to informed treatment planning. This report will describe a confirmatory factor analysis (CFA) of the OSI on youth hospitalized in a psychiatric unit in southwestern Ontario. METHODS: Demographic and self-report data were collected from all youth consecutively admitted to an adolescent in-patient unit who provided consent or assent. RESULTS: The mean age of the sample was 15.71 years (SD = 1.5) and 76 (81 %) were female. The CFA proved the same four function factors relevant, as in the previous study on college students (χ (2)(183) = 231.98, p = .008; χ (2)/df = 1.27; CFI = .91; RMSEA = .05). The model yielded significant correlations between factors (rs = .44-.90, p < .001). Higher NSSI frequency was related to higher scores on each function factor (rs = .24-.29, p < .05), except the External Emotion Regulation factor (r = .11, p > .05). The factor structure of the Addictive Features function was also confirmed (χ (2)(14) = 21.96, p > .05; χ (2)/df = 1.57; CFI = .96; RMSEA = .08). All the items had significant path estimates (.52 to .80). Cronbach's alpha for the Addictive Features scale was .84 with a mean score of 16.22 (SD = 6.90). Higher Addictive Features scores were related to more frequent NSSI (r = .48, p < .001). CONCLUSIONS: Results show further support for the OSI as a valid and reliable assessment tool in adolescents, in this case in a clinical setting, where results can inform case conceptualization and treatment planning.

Role of cytomegalovirus (CMV) IgG avidity testing in diagnosing primary CMV infection during pregnancy.

The risk of intrauterine transmission of cytomegalovirus (CMV) during pregnancy is much greater for women who contract primary CMV infection after conception than for women with evidence of infection (circulating CMV antibodies) before conception. Thus, laboratory tests that aid in the identification of recent primary CMV infection are important tools for managing the care of pregnant women suspected of having been exposed to CMV. CMV IgM detection is a sensitive marker of primary CMV infection, but its specificity is poor because CMV IgM is also produced during viral reactivation and persists following primary infection in some individuals. Studies conducted over the last 20 years convincingly demonstrate that measurement of CMV IgG avidity is both a sensitive and a specific method for identifying pregnant women with recent primary CMV infection and thus at increased risk for vertical CMV transmission. IgG avidity is defined as the strength with which IgG binds to antigenic epitopes expressed by a given protein; it matures gradually during the 6 months following primary infection. Low CMV IgG avidity is an accurate indicator of primary infection within the preceding 3 to 4 months, whereas high avidity excludes primary infection within the preceding 3 months. In this minireview, we summarize published data demonstrating the clinical utility of CMV IgG avidity results for estimating time since primary infection in pregnant women, describe commercially available CMV IgG avidity assays, and discuss some of the issues and controversies surrounding CMV IgG avidity testing during pregnancy.

Performance of a cytomegalovirus IgG enzyme immunoassay kit modified to measure avidity.

The measurement of cytomegalovirus (CMV) IgG avidity accurately discriminates recent and past CMV infections. We sought to determine if the Wampole Laboratories CMV IgG enzyme immunoassay (EIA) could be modified to measure avidity. The evaluation panel consisted of 156 serum samples we used in 2002 to validate a laboratory-developed EIA, in which 78 serum samples exhibited low avidity, 7 exhibited intermediate avidity, and 71 exhibited high avidity. The qualitative agreement between the two avidity assays was 94% (147/156); all 9 sera with discordant results exhibited intermediate avidity in one of the assays. The avidity index (AI) values in the two assays showed excellent correlation (r = 0.96, P < 0.0001). The definition of high avidity was verified for the Wampole assay by demonstrating high avidity in 91/93 (98%) recently collected CMV IgG-positive/IgM-negative serum samples. The performance of the Wampole avidity assay in a reference laboratory setting was assessed using 470 consecutive serum samples submitted for CMV IgG avidity testing. Surprisingly, 101 serum samples were negative when screened for CMV IgG using the Wampole kit per the package insert; 98 of these 101 serum samples were tested using a CMV IgG chemiluminescent immunoassay, and only 5 were positive. Of the 369 CMV IgG-positive samples, 6% exhibited low IgG avidity, 6% exhibited intermediate avidity, and 88% exhibited high avidity; CMV IgM detection rates were inversely related to AI levels. These findings show that (i) the Wampole CMV IgG EIA can be modified to measure CMV IgG avidity, (ii) many samples are apparently submitted for avidity testing without knowledge of their CMV IgG status, and (iii) most CMV IgG-positive sera submitted for avidity testing exhibit high avidity.

Potential impact of different cytomegalovirus (CMV) IgM assays on an algorithm requiring IgM reactivity as a criterion for measuring CMV IgG avidity.

The measurement of cytomegalovirus (CMV) IgG avidity is a powerful tool for identifying individuals with recent CMV infection. Because such patients are expected to be positive for CMV IgM, several investigators have suggested that CMV IgG-positive sera first be screened for CMV IgM and then only the IgM-reactive sera be tested for avidity. We investigated the impact of different CMV IgM assays on such a reflexing algorithm using a panel of 369 consecutive IgG-positive serum samples submitted for avidity testing. A bead-based immunofluorescent assay (BIFA) identified 105 IgM-positive serum samples, whereas an IgM-capture enzyme immunoassay (EIA) identified 48 IgM-positive serum samples; this marked difference led us to evaluate additional CMV IgM assays. An enzyme-linked immunofluorescent assay (ELFA) and a chemiluminescent immunoassay (CIA) were used to test all sera with discordant BIFA/EIA results, all sera with concordant positive results, and selected sera with concordant negative results. The findings indicated that the ELFA would identify 74 CMV IgM-positive samples and the CIA would identify 64. Of the 23 low-avidity serum samples, 2 were IgM negative by BIFA, 3 by ELFA and CIA, and 4 by EIA; of the 23 intermediate-avidity serum samples, 6 were IgM negative by BIFA, 10 by ELFA, and 15 by EIA and CIA. In both these avidity groups, BIFA IgM-negative sera were also negative by the other 3 assays. These findings demonstrate that an algorithm requiring CMV IgM reactivity as a criterion for CMV IgG avidity testing does not identify all low-avidity sera and thus misses some cases of acute CMV infection.

Psychometric properties of the functions and addictive features scales of the Ottawa Self-Injury Inventory: a preliminary investigation using a university sample.

Nonsuicidal self-injury (NSSI) is an issue primarily of concern in adolescents and young adults. Thus far, no single NSSI self-report measure offers a fully comprehensive assessment of NSSI, particularly including measurement of both its functions and potential addictive features. The Ottawa Self-Injury Inventory (OSI) permits simultaneous assessment of both these characteristics; the current study examined the psychometric properties of this measure in a sample of 149 young adults in a university student sample (82.6% girls, Mage = 19.43 years). Exploratory factor analyses revealed 4 functions factors (internal emotion regulation, social influence, external emotion regulation, and sensation seeking) and a single addictive features factor. Convergent evidence for the functions factor scores was demonstrated through significant correlations with an existing measure of NSSI functions and indicators of psychological well-being, risky behaviors, and context and frequency of NSSI behaviors. Convergent evidence was also shown for the addictive features scores, through associations with NSSI frequency, feeling relieved following NSSI, and inability to resist NSSI urges. Additional comment is made regarding the potential for addictive features of NSSI to be both negatively and positively reinforcing. Results show preliminary psychometric support for the OSI as a valid and reliable assessment tool to be used in both research and clinical contexts. The OSI can provide important information for case formulation and treatment planning, given the comprehensive and all-inclusive nature of its assessment capacities.

Adolescent non-suicidal self-injury (NSSI) in German-speaking countries: comparing prevalence rates from three community samples.

PURPOSE: Non-suicidal self-injury (NSSI) has been recognized as a significant mental health problem in adolescence with high prevalence rates. To date, there are few studies that compare rates of adolescent NSSI between different countries. Thus far no prevalence rates of adolescent NSSI have been reported for Austrian or Swiss community samples. METHODS: This study aimed to assess and compare rates of adolescent NSSI in school samples from Austria, Germany and Switzerland using the same assessment instrument (Ottawa Self-Injury Inventory; OSI). RESULTS: Within these countries, 6-month prevalence rates between 7.6 and 14.6% were found, with rates showing significant differences between countries (χ² = 16.54, p = 0.02). CONCLUSIONS: These results demonstrate with some variability the significant rates of NSSI in youth in a cross-country study.

Primary and probable secondary dengue virus (DV) infection rates in relation to age among DV IgM-positive patients residing in the United States mainland versus the Caribbean islands.

Dengue virus (DV) primary infection and probable secondary infection rates in relation to patient age (years) were determined for DV IgM-positive U.S. mainland residents (presumed travelers to areas of DV endemicity) and Caribbean island (area of DV endemicity) residents by evaluating IgG status and IgG avidity. Regardless of place of residence, most patients ≤20 years old exhibited primary infection and most patients >60 years old exhibited probable secondary infection. Among patients 21 to 60 years old, the primary infection rate was markedly higher in U.S. residents.

Utility of IgM/IgG ratio and IgG avidity for distinguishing primary and secondary dengue virus infections using sera collected more than 30 days after disease onset.

Dengue virus (DV) IgM/IgG ratio and IgG avidity value (AV) can reliably distinguish between primary and secondary DV infections using sera collected within 30 days of disease onset, but little is known about their efficacies using sera collected >30 days after onset. To investigate this issue, we analyzed specimens submitted to our reference laboratory for DV antibody testing. We first classified patients as having primary (n = 55) or secondary (n = 58) infections based on seroconversion patterns in a comparison of two sera collected <30 days apart. We then evaluated IgM/IgG ratios and IgG AVs of the second specimens by using receiver operating characteristic curve analysis. The IgM/IgG ratio that best discriminated primary from secondary infection was 1.32; 95% of 55 primary infections exhibited ratios of >1.32, whereas 93% of 58 secondary infections exhibited ratios of ≤1.32. The discriminatory AV was 0.39; 95% of 41 primary infections exhibited AVs of ≤0.39, whereas 95% of 38 secondary infections exhibited AVs of >0.39. We then evaluated the IgM/IgG ratios and AV for primary-infection patients whose second serum samples were collected ≥30 days after the first serum samples; only 56% of 27 sera exhibited ratios of >1.32, whereas 81% of 21 sera exhibited AVs of ≤0.39. Assuming that the first specimens were collected within a week after symptoms appeared, these findings indicate that IgG AV is superior to the IgM/IgG ratio for distinguishing primary from secondary DV infections when using samples collected more than 5 weeks after disease onset.

Comparison of the Babesia duncani (WA1) IgG detection rates among clinical sera submitted to a reference laboratory for WA1 IgG testing and blood donor specimens from diverse geographic areas of the United States.

All reported cases of WA1 babesiosis have occurred in the Pacific coast region of the United States, suggesting that WA1 is limited to this geographic area. However, we detected WA1 IgG in 27% of clinical sera sent to our laboratory for WA1 IgG testing from across the United States over a 2-year period, suggesting that exposure to WA1 or a closely related organism occurs outside Pacific coast states. We sought to determine if this high WA1 IgG detection rate among clinical specimens merely reflects WA1 seroprevalence outside the Pacific region. WA1 IgG, as well as Babesia microti IgG, was measured in 900 blood donor specimens from 9 states. Overall seroprevalence was 2.0% for WA1 and 0.4% for B. microti; regional seroprevalences ranged from 0 to 4% and 0 to 2%, respectively. Additional studies were performed to determine if WA1 IgG reactivity was attributable to polyclonal B-cell activation associated with acute Epstein-Barr virus (EBV) infection; 40 WA1 IgG-positive clinical sera and the 18 WA1 IgG-positive blood donor specimens were all negative for EBV capsid antigen (EBVCA) IgM (a marker of acute EBV infection), and 40 EBVCA IgM-positive sera were all negative for WA1 IgG. These findings indicate that the high WA1 IgG detection rate among clinical specimens does not simply reflect the national WA1 seroprevalence among blood donors or nonspecific reactivity due to acute EBV infection. Rather, the findings suggest that infection with WA1 or a related organism is more common than indicated by the literature and is not limited to Pacific coast states.