Diagnostic accuracy of optical coherence tomography angiography in the detection of neovasculature in age-related macular degeneration: a meta-analysis.

This work is a systematic review and meta-analysis to evaluate the diagnostic accuracy of optical coherence tomography angiography (OCTA) in the identification of choroidal neovascularization due to age-related macular degeneration (AMD) in comparison with fluorescein angiography (FA). A systematic search of the literature was carried out on Medline, EMBASE, Web of Science, Cochrane Library and Center for Reviews and Dissemination. Studies comparing OCTA with FA for the diagnosis of choroidal neovascularization due to AMD that included data on the diagnostic validity of the test or the data necessary for its calculation were selected. The QUADAS-2 tool was used to assess the risk of bias in selected studies. The quantitative analysis of the results was performed by meta-analysis. Seven primary studies were included. The quality of the evidence was good. The total population included in the meta-analysis comprised 553 eyes, with a cumulative sensitivity and specificity of 85.9% (95% CI 81.9-89.3%) and 89% (95% CI 83.5-93.2%), respectively, cumulative positive and negative likelihood ratios of 8.36 and 0.15, respectively (95% CI of 3.05-22.890 and 0.09-0.24, respectively), and a cumulative diagnostic odds ratio of 67.21 (95% CI 22.58-200.05). The evidence obtained does not demonstrate the superiority of OCTA over FA. Its use as a support technique could improve patient flow and reduce the number of FA.

ImmunoCAP ISAC in food allergy diagnosis: a systematic review of diagnostic test accuracy.

OBJECTIVE: To assess the diagnostic test accuracy of the component-resolved diagnosis device ImmunoCAP ISAC, compared with oral food challenge. DESIGN: Systematic review reported according to the PRISMA-DTA recommendations. DATA SOURCES: Medline, Embase and Cochrane Library databases were searched from inception to May 2019 and updated in March 2021. ELIGIBILITY CRITERIA FOR SELECTING STUDIES: We included diagnostic test accuracy studies comparing ISAC component results as the index test with oral food challenge as the reference test, in people of any age suspected of IgE mediated food allergy to milk, egg, peanut, shrimp, hake, apple, peach, kiwi, melon, walnut, hazelnut, wheat or pineapple. Risk of bias was evaluated using the QUADAS-2 tool. RESULTS: We screened 799 titles and included 11 studies - seven prospective and two retrospective cohort studies, two case-control studies. Included studies evaluated IgE to Gald1 (three studies, 300 participants, 140 with egg allergy), Bosd5 (three studies, 242 participants, 146 with milk allergy) and Arah1 or 2 (seven studies, 546 participants, 346 with peanut allergy). No studies were identified for other ISAC components. Risk of bias was high or unclear mainly due to inadequate blinding. Applicability was of high or unclear concern due to unclear thresholds, inappropriate exclusions and variable populations. Gald1 sensitivity ranged from 58 to 84%, specificity 87%-97%. Bosd5 sensitivity 24%-40%, specificity 94%-95%. Arah1 sensitivity 45%-91%, specificity 41%-93%. Arah2 sensitivity 70%-94%, specificity 75%-95%. CONCLUSIONS: Diagnostic test accuracy information for ISAC components was only available for milk, egg and peanut. Specificity is generally higher than sensitivity, which contrasts with the performance of skin prick and standard specific IgE tests for diagnosing food allergy. Higher quality information is needed to determine the clinical utility of ISAC for food allergy diagnosis. SYSTEMATIC REVIEW REGISTRATION: Not registered.

Screening for Gestational Diabetes Mellitus by Measuring Glycated Hemoglobin Can Reduce the Use of the Glucose Challenge Test.

BACKGROUND: Physiological changes during pregnancy, such as dilutional anemia and a reduced half-life of red blood cells, have prevented the use of glycated Hb (HbA1c) as a biomarker for gestational diabetes mellitus (GDM). Nevertheless, increasing evidence supports the use of HbA1c in GDM diagnostic strategies.We studied HbA1c as a biomarker of GDM and its possible use as a screening test to avoid the use of the glucose challenge test (GCT). METHODS: This case-control study involved 607 pregnant women between the 24th and 28th week of gestation. HbA1c level was determined, and GDM was diagnosed according to the National Diabetes Data Group criteria. The area under the ROC curve (AUC) was determined; two low and two high cut-off points were established to rule out GDM and classify high-risk pregnant women, respectively. For each cut-off, sensitivity (S), specificity (SP), and total number and percentage of GCTs avoided were determined. RESULTS: The AUC for HbA1c diagnostic performance was 0.68 (95% confidence interval 0.57-0.79). Using 4.6% HbA1c (27 mmol/mol) as the lower cut-off (S=100%), 14% of participants could avoid the GCT. Using 5.5% HbA1c (36 mmol/mol) as the upper cut-off (SP =94.5%), 6% of participants would be considered at high risk. CONCLUSIONS: HbA1c can be used as a screening test prior to the GCT, thereby reducing the need for the GCT among pregnant women at a low risk of GDM.

Fasting Glycemia as Screening Tool to Rule-Out Gestational Diabetes in Low-Risk Population.

BACKGROUND: The use of a glucose challenge test as the universal screening for gestational diabetes is common in many countries. This test represents significant costs for laboratories and inconveniences for the patients, who have to wait for one hour and, very often, feel discomfort and nausea. In this work we propose the use of fasting glycemia, in a population with low prevalence of gestational diabetes as a pre-screening test that would avoid the oral glucose overload in those pregnant women with low risk of gestational diabetes. METHODS: The study was done with the fasting glucose levels of 6,573 pregnant women who underwent a two steps strategy to screen for gestational diabetes, a first step consisting of a 50 g glucose challenge test, followed when glycemia ≥ 140 mg/dL by a 100 g Oral Glucose Tolerance Test, based on recommendations made by National Diabetes Data Group. RESULTS: The ROC curve for fasting glucose was calculated, and we obtained an AUC = 0.633 (0.569 - 0.696). The sensitivity, specificity, and predictive values were established for different thresholds. CONCLUSIONS: We proposed that women with fasting glycemia ≤ 62 mg/dL, (S = 91.3%, NPV = 98.79% and LR- = 0.87) are in low risk of suffering gestational diabetes, which means that 10% of our population would not undergo the glucose challenge test.

Comparison of automated devices UX-2000 and SediMAX/AutionMax for urine samples screening: A multicenter Spanish study.

OBJECTIVES: In this study we aim to compare UX2000 (Sysmex Corp, Japan) and SediMAX/AutionMax (Arkray Factory Inc., Japan), totally automatized analyzers, against Fuchs-Rosenthal counting chamber, the gold standard technique for sediment analysis. DESIGN AND METHODS: Urine samples of 1454 patients from three Spanish hospitals were assessed for red and white blood cells (RBC; WBC) using three different techniques: flow cytometry, image-based method and Fuchs-Rosenthal counting chamber. Test strip results were subjected to concordance evaluation. Agreement was assessed by Cohen's weighted kappa for multinomial results. Sensitivity (SE) and specificity (SP) were calculated. RESULTS: The categorization of the results showed that UX-2000 had higher concordance over SediMAX for WBC (0.819 vs. 0.546) and similar for RBC (0.573 vs. 0.630). For RBC, UX-2000 had higher SE (92.7% vs. 80.3%) but lower SP (77.1% vs. 87.4%), and showed higher both SE (94.3% vs. 76.7%) and SP (94.7% vs. 88.2%) for WBC. Inter-devices test strip agreement was substantial (kappa>0.600) for all variables except for bilirubin (kappa: 0.598). Intra-device test strip agreement was similar for UX2000 and SediMAX with regard to RBC (kappa: 0.553 vs. 0.482) but better for UX2000 with regard to WBC (0.688 vs. 0.465). CONCLUSIONS: Both analyzers studied are acceptable for daily routine lab work, even though SediMAX is easier to use in laboratories thanks to its lower maintenance procedure. UX-2000 has shown to have better concordance with the gold standard method. However, it needs some improvements such as an image module in order to decrease manual microscopy review for urine samples.

Evaluation of Bio-Rad D-100 HbA1c analyzer against Tosoh G8 and Menarini HA-8180V.

OBJECTIVES: To evaluate the Bio-Rad D-100®, an HPLC analyzer for glycated hemoglobin (HbA1c) determination, and to compare its performance with the Menarini HA-8180V® and Sysmex G8®. METHODS: Method comparison was performed according to Clinical and Laboratory Standards Institute (CLSI) EP9-A2 guidelines. We selected 100 samples from the routine laboratory workload and analyzed them in duplicate with the three analyzers. The imprecision study was performed according to CLSI EP5-A2 guidelines for both inter-assay and intra-assay variability. Bias was assessed with external quality control material. To establish linearity, CLSI EP6-A protocol was followed. RESULTS: Method comparison (95% confidence intervals in parentheses): D-100 vs G8: Passing-Bablok regression; y=0.973(0.963-0.983)×-0.07(-0.07-0.069); r=0.9989. Bland-Altman mean difference: -0.229%HbA1c (-0.256: -0.202); Relative bias plot: D-100/G8 vs D100-G8 mean ratio=0.971(0.967-0.975). D-100 vs HA-8180V: Passing-Bablok regression; y=0.944(0.932-0.958)×-0.078(0.024-0.173); r=0.9989. Bland-Altman mean difference: -0.363%HbA1c (-0.401: -0.325); Relative bias plot D-100/HA-8180V vs D100-HA-8180V mean ratio=0.955(0.952-0.958). Inter-assay coefficient of variation (CV): 0.81%. Intra-assay CV: 1.04% (low level), and 0.78% (high level). Bias against target value=2.332%. Linearity: r2=0.998 in the concentration range 4.4-13.9%HbA1c. Carry-over: 0.0024%. CONCLUSIONS: The Bio-Rad D-100 shows good correlation with G8 and HA-8180V. There is a small proportional systematic difference (2.7% and 5.6%, respectively) in both comparisons. Inter and intra-assay CVs are both lower than the lowest CV obtained in studies performed with D-100 and other instruments.

Voltammetric discrimination of skatole and indole at disposable screen printed electrodes.

In this work, we study the electrochemical behaviour of skatole, one of the compounds responsible for the offensive smell in pork meat that is known as boar taint, at different metal and carbon electrodes. We then demonstrate for the first time that skatole and indole, the main electroactive interferent potentially present in real samples, can be discriminated and separately quantified using cheap and disposable screen printed electrodes (SPE). This implies significant progress compared to the colorimetric method reported by Mortensen in 1983.

Improved bacteria detection by coupling magneto-immunocapture and amperometry at flow-channel microband electrodes.

This paper describes the first immunosensing system reported for the detection of bacteria combining immunomagnetic capture and amperometric detection in a one-step sandwich format, and in a microfluidic environment. Detection is based on the electrochemical monitoring of the activity of horseradish peroxidase (HRP), an enzyme label, through its catalysis of hydrogen peroxide (H(2)O(2)) in the presence of the mediator hydroquinone (HQ). The enzymatic reaction takes place in an incubation micro-chamber where the magnetic particles (MPs) are confined, upstream from the working electrode. The enzyme product is then pumped along a microchannel, where it is amperometrically detected by a set of microelectrodes. This design avoids direct contact of the biocomponents with the electrode, which lowers the risk of electrode fouling. The whole assay can be completed in 1h. The experiments performed with Escherichia coli evidenced a linear response for concentrations ranging 10(2)-10(8) cell ml(-1), with a limit of detection of 55 cells ml(-1) in PBS, without pre-enrichment steps. Furthermore, 100 cells ml(-1) could be detected in milk, and with negligible interference by non-target bacteria such as Pseudomonas.