Evaluation of the applicability of internal controls on self-collected samples for high-risk human papillomavirus is needed.

BACKGROUND: Self-collection of cervical samples to detect high-risk human papillomavirus (hr-HPV) is a trending topic in primary cervical cancer screening. This study evaluates the applicability of a self-sampling device to routine molecular procedures for hr-HPV detection. METHODS: In a primary health care facility in Kinshasa, Congo, 187 self-collected samples (Evalyn Brush) were gathered and sent to Ghent University Hospital (UZ Ghent) and Algemeen Medisch Labo (AML) in Belgium where routine tests for hr-HPV were applied (Abbott RealTime hr-HPV and qPCR (E6/E7), respectively). Sample type effect was evaluated by comparing the internal control (IC) between the self-collected samples and routine, clinician-taken samples randomly selected from the UZ Ghent archive. RESULTS: In UZ Ghent an error was encountered in 9.1% (17/187) of self-collected samples due to a lack of IC signal. The hr-HPV prevalence in the remaining 170 samples was 18,8%. Comparing IC results between the self-collected and clinician-collected groups, a significant difference (p < 0,001) was found, with higher IC signals in the clinician-collected group. In AML, an error was encountered in 17.6% (33/187) of samples, including 16/17 of the UZ Ghent. The remaining sample with IC error gave a negative result in AML. Among the 154 samples without IC error at AML, a correlation of 90% was seen between both laboratories with a 77% negativity rate. CONCLUSION: Testing the self-collected specimens by 2 routine hr-HPV tests gave a high IC error rate (9.1-17.6%). A possible solution would be to differentiate cut-offs for IC values depending on sample type, as currently used cut-offs are set for clinician-taken samples.

Cycle Threshold Probability Score for Immediate and Sensitive Detection of B.1.351 SARS-CoV-2 Lineage.

BACKGROUND: Detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants of concern associated with immune escape is important to safeguard vaccination efficacy. We describe the potential of delayed N gene amplification in the Allplex SARS-CoV-2 Assay (Seegene) for screening of the B.1.351 (20H/501.V2, variant of concern 2 [VOC.V2], South African SARS-CoV-2 variant) lineage. METHODS: In a study cohort of 397 consecutive polymerase chain reaction-positive samples genotyped by whole-genome sequencing, amplification curves of E/N/S-RdRP targets indicated delayedN vs E gene amplification characteristic of B.1.351. Logistic regression was used to calculate a VOC.V2 probability score that was evaluated as a separate screening test in an independent validation cohort vs sequencing. RESULTS: B.1.351 showed a proportionally delayed amplification of the  N vs E gene. In logistic regression, only N and E gene cycle thresholds independently contributed to B.1.351 prediction, allowing calculation of a VOC.V2 probability score with an area under the curve of 0.94. At an optimal dichotomous cutoff point of 0.12, the VOC.V2 probability score achieved 98.7% sensitivity at 79.9% specificity, resulting in a negative predictive value (NPV) of 99.6% and a positive predictive value of 54.6%. The probability of B.1.351 increased with an increasing VOC.V2 probability score, achieving a likelihood ratio of 12.01 above 0.5. A near-maximal NPV was confirmed in 153 consecutive validation samples. CONCLUSIONS: Delayed N vs E gene amplification in the Allplex SARS-CoV-2 Assay can be used for fast and highly sensitive screening of B.1.351.

Multicenter evaluation of the FilmArray Meningitis/Encephalitis assay in a routine setting.

Introduction. The FilmArray Meningitis/Encephalitis (FA-ME) Panel (Biofire, Salt Lake City, Utah, US) enables fast and automated detection of 14 pathogens in cerebrospinal fluid (CSF).Gap statement. The performance of the FA-ME panel in a real routine setting has not yet been described and could lead to better patient management in cases of good performance.Aim. This multicenter study verified the FA-ME panel analytical performance in a routine hospital setting.Methodology. Between April 2016 and April 2018, 454 CSF samples were analysed with the FA-ME panel and compared with routine diagnostics. In cases of discrepancy or lack of a comparator result, a profound analysis based on patient records and other laboratory results was performed.Results. A first analysis of 65 frozen samples, suspicious for meningitis had a 89 % concordance with routine diagnostics. The limit of detection (LOD) was confirmed for all pathogens except for Streptococcus agalactiae and a strain of Haemophilus influenzae (Escherichia coli K1 and Cryptococcus gattii LOD experiments were not performed). The routine evaluation showed a positive result in 114 (25 %) clinical samples for at least one target. In three samples co-infections were found. After discrepancy analysis, overall sensitivity was 98 % (false negative FA-ME results for one HSV2, two HSV1 and two parechovirus). Four FA-ME results were considered false positive (two HHV6, one VZV and one E. coli K1), resulting in an overall specificity of >99 %. A clinical added value of the assay was seen in the diagnosis of eight cases of bacterial meningitis.Conclusion. Because of its rapidity and ease of use, the FA-ME panel has great potential in the diagnosis of central nervous infections. Implementation can improve clinical management, but costs and analytical limitations need to be addressed to convince clinicians and laboratories of its value.

Performance Evaluation of the Siemens SARS-CoV-2 Total Antibody and IgG Antibody Test.

OBJECTIVE: In this study, the performance of 2 commercially available SARS-CoV-2 antibody assays is evaluated. METHODS: The Siemens SARS-CoV-2 Total (COV2T) and IgG (COV2G) antibody tests were evaluated on a Siemens Atellica IM1300 analyzer. Imprecision was assessed with the CLSI EP15 protocol using positive controls. Ninety control group specimens were analyzed for specificity, and 175 specimens from 58 patients with polymerase chain reaction-confirmed SARS-CoV-2 were measured for the sensitivity and kinetics of the antibody response. RESULTS: Within-run and total imprecision were acceptable for both assays. Both tests showed a specificity of 100%. Sensitivity earlier in the disease state was greater for the COV2T assay than for the COV2G assay, but sensitivity >14 days after onset of symptoms approached 100% for both. For all patients, antibody titers remained above the seroconversion cutoff for all follow-up specimens. CONCLUSION: This study shows acceptable performance for both the Siemens COV2T and COV2G test, although seroconversion occurs earlier with the COV2T test.

Infection prevention and control challenges in Flemish homecare nursing: a pilot study.

Home nursing is evolving towards more invasive care. Nevertheless, no national data are available on the prevalence of HAI in this setting. The aim of this pilot study is to explore the Flemish home care setting as a first step toward a national surveillance program. A survey, focused on patient characteristics and HAI, was conducted between 7 May and 20 July 2018 on 711 Flemish patients. Most of the patients (74%) are 65 years or older and half of them had a form of comorbidity. Assisting with personal hygiene and wound care were the most frequent services delivered by home care nurses. A comparison of the prevalence of infections diagnosed by a physician or applying uniform criteria (ECDC), revealed a similar prevalence of skin and soft tissue infections (9% vs. 8.5%) and urinary tract infections (4% vs. 4.5%). A positive MDRO-screening was found in 6% of the patients. This pilot study is a first step towards a standardized national surveillance in home care to collect information on the prevalence of HAI and it reveals several interesting facts and study pitfalls for this setting.

The impact of repeated freeze-thaw cycles on antiphospholipid antibody titer.

BACKGROUND: Pre-analytical factors, like freeze-thaw cycles (FTC), can potentially affect results and clinical interpretation. According to the SSC-ISTH recommendations for antiphospholipid antibodies (aPL) testing, additional FTC should be avoided to maintain the best performance. Patient samples are often analyzed in batch and having one frozen sample aliquot for all aPL tests, that may hamper daily routine work-out. To use them for study or method validation purpose, sample storage in bio banks is often done in one aliquot also triggering the need for several FTC to be able to use them in different scientific projects. Taking into account the limited scientific literature, the strict guidelines and the potential benefits of repeated FTC we evaluated this pre-analytical factor. OBJECTIVES: Evaluating the effect of repeated FTC on anticardiolipin (aCL) IgM/IgG and anti-beta-2 glycoprotein 1 (aß2GPI) IgM/IgG antibody titer. PATIENT/METHODS: 42 patient plasmas that were not thawed before, were retrieved from the routine archive (-80°C). All aliquots were analyzed on five consecutive days with an additional, standardized FTC every day. Mann-Withney tests for statistical differences and a concordance correlation coefficient (CCC) were calculated between the first and following FTC. RESULTS AND CONCLUSION: For all four aPL no statistical difference or degradation from positive to negative was seen, even after five FTC. The CCC between the first and fifth FTC were between 0.98 and 1 for all four aPL. aCL IgM/IgG and aß2GPI IgM/IgG antibody titer, over a broad titer range, are stable over time and after repeated FTC.

Evaluation of the CellaVision DM96 advanced RBC application for screening and follow-up of malaria infection.

CellaVision DM96 is a digital cell morphology system for automated classification of white and red blood cells. CellaVision Advanced RBC application (ARBCA) pre-classifies RBC in 21 categories, including parasitized RBC, and allows re-classification by the operator. In this study, the performance of the software for detection of malaria and calculation of parasitemia was evaluated and compared to microscopy (n=40). For CellaVision, both pre- and post-reclassification results were evaluated. Sensitivity was moderate, even post-reclassification (72%), due to low numbers of analyzed RBC and limited resolution of photographs. CellaVision results correlated with microscopy according to Passing-Bablok analysis, with slightly lower values for CellaVision. Within-run, between-run and inter-observer variability were acceptable. The low sensitivity of CellaVision ARBCA precludes its use as a screening technique for malaria. However, due to its good correlation with microscopy and short turn-around-times, it may be useful in follow-up of parasitemia. Larger studies are required to confirm these findings.