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A new analysis shows that the extra step of performing lymph node biopsy has no benefits but may cause harm in older women with ductal carcinoma in situ (DCIS).
Medscape Medical News

New data highlight the need for more focused efforts to diagnose and treat hypertension and prevent its development in the black population.
Medscape Medical News

With biomarkers for disease severity in neurosarcoidosis lacking, clinical utility may be found with the albumin index, a measure of blood-brain barrier permeability, new research suggests.
Medscape Medical News

Showing a survival advantage for targeted therapy over chemotherapy, this trial has been hailed as practice changing, but it has now also been criticized for lack of detail.
Medscape Medical News

Asti - indeterminato di: un posto di dirigente medico di patologia clinica per la S.C. Laboratorio analisi... pubblici, per titoli ed esami, per la copertura di quattro posti di dirigente medico, a tempo...

Lavorint - Termoli, Campobasso - La Filiale di Campobasso, seleziona per laboratorio medico: INFERMIERA PROFESSIONALE...

BACKGROUND:

For medical tests that have a central role in clinical decision-making, current guidelines advocate outcome-based analytical performance specifications. Given that empirical (clinical trial-style) analyses are often impractical or unfeasible in this context, the ability to set such specifications is expected to rely on indirect studies to calculate the impact of test measurement uncertainty on downstream clinical, operational, and economic outcomes. Currently, however, a lack of awareness and guidance concerning available alternative indirect methods is limiting the production of outcome-based specifications. Therefore, our aim was to review available indirect methods and present an analytical framework to inform future outcome-based performance goals.

CONTENT:

A methodology review consisting of database searches and extensive citation tracking was conducted to identify studies using indirect methods to incorporate or evaluate the impact of test measurement uncertainty on downstream outcomes (including clinical accuracy, clinical utility, and/or costs). Eighty-two studies were identified, most of which evaluated the impact of imprecision and/or bias on clinical accuracy. A common analytical framework underpinning the various methods was identified, consisting of 3 key steps: (a) calculation of "true" test values; (b) calculation of measured test values (incorporating uncertainty); and (c) calculation of the impact of discrepancies between (a) and (b) on specified outcomes. A summary of the methods adopted is provided, and key considerations are discussed.

CONCLUSIONS:

Various approaches are available for conducting indirect assessments to inform outcome-based performance specifications. This study provides an overview of methods and key considerations to inform future studies and research in this area.

BACKGROUND:

Gardnerella vaginalis is implicated as one of the causative agents of bacterial vaginosis, but it can also be isolated from the vagina of healthy women. Previous efforts to study G. vaginalis identified 4 to 6 clades, but average nucleotide identity analysis indicates that G. vaginalis may be multiple species. Recently, Gardnerella was determined to be 13 genomospecies, with Gardnerella piottii, Gardnerella leopoldii, and Gardnerella swidsinkii delineated as separate species.

METHODS:

We accessed 103 publicly available genomes annotated as G. vaginalis. We performed comprehensive taxonomic and phylogenomic analysis to quantify the number of species called G. vaginalis, the similarity of their core genes, and their burden of their accessory genes. We additionally analyzed publicly available metatranscriptomic data sets of bacterial vaginosis to determine whether the newly delineated genomospecies are present, and to identify putative conserved features of Gardnerella pathogenesis.

RESULTS:

Gardnerella could be classified into 8 to 14 genomospecies depending on the in silico classification tools used. Consensus classification identified 9 different Gardnerella genomospecies, here annotated as GS01 through GS09. The genomospecies could be readily distinguished by the phylogeny of their shared genes and burden of accessory genes. All of the new genomospecies were identified in metatranscriptomes of bacterial vaginosis.

CONCLUSIONS:

Multiple Gardnerella genomospecies operating in isolation or in concert with one another may be responsible for bacterial vaginosis. These results have important implications for future efforts to understand the evolution of the Gardnerella genomospecies, host–pathogen interactions of the genomospecies during bacterial vaginosis, diagnostic assay development for bacterial vaginosis, and metagenomic investigations of the vaginal microbiota.

BACKGROUND:

Currently, several indole markers are measured separately to support diagnosis and follow-up of patients with neuroendocrine tumors (NETs). We have developed a sensitive mass spectrometry method that simultaneously quantifies all relevant tryptophan-related indoles (tryptophan, 5-hydroxytryptophan, serotonin, 5-hydroxyindoleacetic acid) in platelet-rich plasma. Direct-matrix derivatization was used to make the chemical properties of the indoles uniform and to improve the analytical sensitivity and specificity of the assay.

METHODS:

In situ derivatization was performed directly in platelet-rich plasma with propionic anhydride at an ambient temperature. The derivatized indoles were extracted by online solid-phase extraction and eluted to the analytical column for separation followed by mass spectrometric detection. The method was validated according to international guidelines. Platelet-rich plasma samples from 68 healthy individuals and 40 NET patients were analyzed for tryptophan, 5-hydroxytryptophan, serotonin, and 5-hydroxyindoleacetic acid.

RESULTS:

The method reproducibly quantified relevant indoles in 8.5 min, including online sample cleanup. Intra- and interassay imprecision, evaluated at 3 different concentrations, ranged from 2.0% to 12% and 1.9% to 13%, respectively. The limit of quantification was sufficient to measure endogenous concentrations of all 4 indoles. Healthy individuals and NET patients had different concentrations of 5-hydroxytryptophan, serotonin, and 5-hydroxyindoleacetic acid, but tryptophan concentrations were the same.

CONCLUSIONS:

Direct-matrix derivatization in combination with LC-MS/MS is a powerful tool for the simultaneous quantification of all tryptophan-related indoles in platelet-rich plasma. Simultaneous profiling of relevant indoles improves the biochemical characterization and follow-up of NETs.

BACKGROUND:

Measurement of plasma adrenocorticotropic hormone (ACTH) is key in the differential diagnosis of hypothalamic-pituitary-adrenal disorders. Two-site sandwich immunoassays dominate clinical testing of ACTH in North America; however, discordant results between manufacturers have been repeatedly reported. To resolve the discrepancy, we developed a liquid chromatography–tandem mass spectrometry (LC-MS/MS) assay for the intended measurand, biologically active intact ACTH (iACTH).

METHODS:

The multiple reaction monitoring LC-MS/MS assay was designed to selectively measure full-length iACTH, as well as ACTH analogs and fragments (i.e., ACTH1–24 and ACTH18–39). Epitope assignment of the Roche Elecsys antibodies was performed by MALDI-TOF mass spectrometry. A method comparison between Roche Elecsys and Siemens Immulite ACTH immunoassays was performed and clinically concordant/discordant results identified. In a subset of these samples, the iACTH concentration was determined using the LC-MS/MS method.

RESULTS:

The lower limit of the measuring interval of the iACTH LC-MS/MS assay was 9 pg/mL (2 pmol/L). The assay was linear from 9 to 1938 pg/mL (2 to 427 pmol/L). Epitope mapping revealed that the Roche capture and detection antibodies bound residues 9–12 and 36–39 of ACTH, respectively. The iACTH LC-MS/MS analysis demonstrated that for discordant results between 2 immunoassays studied, only the Roche results were highly positively correlated with the iACTH concentration.

CONCLUSIONS:

Immunoprecipitation of biologically active ACTH molecules followed by LC-MS/MS analysis enabled selective detection of iACTH and relevant biologically active fragments in plasma. Applied to the investigation of clinically discrepant results, this method can act as an arbiter of the concentration of iACTH present.

BACKGROUND:

Circulating tumor DNA (ctDNA) assays are increasingly used for clinical decision-making, but it is unknown how well different assays agree. We aimed to assess the agreement in ctDNA mutation calling between BEAMing (beads, emulsion, amplification, and magnetics) and droplet digital PCR (ddPCR), 2 of the most commonly used digital PCR techniques for detecting mutations in ctDNA.

METHODS:

Baseline plasma samples from patients with advanced breast cancer enrolled in the phase 3 PALOMA-3 trial were assessed for ESR1 and PIK3CA mutations in ctDNA with both BEAMing and ddPCR. Concordance between the 2 approaches was assessed, with exploratory analyses to estimate the importance of sampling effects.

RESULTS:

Of the 521 patients enrolled, 363 had paired baseline ctDNA analysis. ESR1 mutation detection was 24.2% (88/363) for BEAMing and 25.3% (92/363) for ddPCR, with good agreement between the 2 techniques ( = 0.9l; 95% CI, 0.85–0.95). PIK3CA mutation detection rates were 26.2% (95/363) for BEAMing and 22.9% (83/363) for ddPCR, with good agreement ( = 0.87; 95% CI, 0.81–0.93). Discordancy was observed for 3.9% patients with ESR1 mutations and 5.0% with PIK3CA mutations. Assessment of individual mutations suggested higher rates of discordancy for less common mutations (P = 0.019). The majority of discordant calls occurred at allele frequency <1%, predominantly resulting from stochastic sampling effects.

CONCLUSIONS:

This large, clinically relevant comparison showed good agreement between BEAMing and ddPCR, suggesting sufficient reproducibility for clinical use. Much of the observed discordancy may be related to sampling effects, potentially explaining many of the differences in the currently available ctDNA literature.

BACKGROUND:

Long-term complications of type 2 diabetes (T2D), such as macrovascular and microvascular events, are the major causes for T2D-related disability and mortality. A clinically convenient, noninvasive approach for monitoring the development of these complications would improve the overall life quality of patients with T2D and help reduce healthcare burden through preventive interventions.

METHODS:

A selective chemical labeling strategy for 5-hydroxymethylcytosines (5hmC-Seal) was used to profile genome-wide 5hmCs, an emerging class of epigenetic markers implicated in complex diseases including diabetes, in circulating cell-free DNA (cfDNA) from a collection of Chinese patients (n = 62). Differentially modified 5hmC markers between patients with T2D with and without macrovascular/microvascular complications were analyzed under a case–control design.

RESULTS:

Statistically significant changes in 5hmC markers were associated with T2D-related macrovascular/microvascular complications, involving genes and pathways relevant to vascular biology and diabetes, including insulin resistance and inflammation. A 16-gene 5hmC marker panel accurately distinguished patients with vascular complications from those without [testing set: area under the curve (AUC) = 0.85; 95% CI, 0.73–0.96], outperforming conventional clinical variables such as urinary albumin. In addition, a separate 13-gene 5hmC marker panel could distinguish patients with single complications from those with multiple complications (testing set: AUC = 0.84; 95% CI, 0.68–0.99), showing superiority over conventional clinical variables.

CONCLUSIONS:

The 5hmC markers in cfDNA reflected the epigenetic changes in patients with T2D who developed macrovascular/microvascular complications. The 5hmC-Seal assay has the potential to be a clinically convenient, noninvasive approach that can be applied in the clinic to monitor the presence and severity of diabetic vascular complications.

BACKGROUND:

Increases in cardiac and stress biomarkers may be associated with loss of kidney function through shared mechanisms involving cardiac and kidney injury. We evaluated the associations of cardiac and stress biomarkers [N-terminal pro-B-type natriuretic peptide (NT-proBNP), high-sensitivity troponin T (hsTnT), growth differentiation factor 15 (GDF-15), soluble ST-2 (sST-2)] with progression of chronic kidney disease (CKD).

METHODS:

We included 3664 participants with CKD from the Chronic Renal Insufficiency Cohort study. All biomarkers were measured at entry. The primary outcome was CKD progression, defined as progression to end-stage renal disease (ESRD) or 50% decline in estimated glomerular filtration rate (eGFR). Cox models tested the association of each biomarker with CKD progression, adjusting for demographics, site, diabetes, cardiovascular disease, eGFR, urine proteinuria, blood pressure, body mass index, cholesterol, medication use, and mineral metabolism.

RESULTS:

There were 1221 participants who had CKD progression over a median (interquartile range) follow-up of 5.8 (2.4–8.6) years. GDF-15, but not sST2, was significantly associated with an increased risk of CKD progression [hazard ratios (HRs) are per SD increase in log-transformed biomarker]: GDF-15 (HR, 1.50; 95% CI, 1.35–1.67) and sST2 (HR, 1.07; 95% CI, 0.99–1.14). NT-proBNP and hsTnT were also associated with increased risk of CKD progression, but weaker than GDF-15: NT-proBNP (HR, 1.24; 95% CI, 1.13–1.36) and hsTnT (HR, 1.11; 95% CI, 1.01–1.22).

CONCLUSIONS:

Increases in GDF-15, NT-proBNP, and hsTnT are associated with greater risk for CKD progression. These biomarkers may inform mechanisms underlying kidney injury.