Expert opinion on medical diagnostics最新文献

Objective: Self-monitoring of blood glucose is a key element in diabetes management. Accurate and precise performance of blood glucose monitors (BGMs) ensures that valid values are obtained to guide treatment decisions by patients and physicians. BGStar and iBGStar are hand-held BGMs that use dynamic electrochemistry to correct for potential interferences and thereby minimize system errors.

Research design and methods: A single-center, in vitro diagnostic device performance evaluation with heparinized oxygenated venous blood samples (intra-assay precision) and control solutions (interassay precision) was performed in a laboratory setting, comparing BGStar and iBGStar with 12 competitors.

Main outcome measures: The primary outcome was the coefficient of variation percent (CV%) of the BGMs investigated.

Results: In inter-assay precision analyses, all but GlucoMen LX had a CV <5%, and in intra-assay precision analyses, 10 of the 14 devices tested had CV <5%. BGStar and iBGStar had a CV <5% in both the inter- and intra-assay precision analyses. The smallest variation was found in the near-normoglycemic glucose range (5.3 - 8.0 mmol/l) for both BGStar and iBGStar in the inter-assay precision analysis.

Conclusions: BGStar and iBGStar were proven to have very good inter-assay and high intra-assay precision, demonstrating low scattering of replicate measurements with both clinical samples and control solutions.

Introduction: Computed tomography (CT) has become key for patient management due to its outstanding capabilities for detecting disease processes and assessing treatment response, which has led to expansion in CT imaging for diagnostic and image-guided therapeutic interventions. Despite these benefits, the growing use of CT has raised concerns as radiation risks associated with radiation exposure.

Areas covered: The purpose of this article is to familiarize the reader with fundamental concepts of dose metrics for assessing radiation exposure and weighting radiation-associated risks. The article also discusses general approaches for reducing radiation dose while preserving diagnostic quality. The authors provide additional insight for undertaking protocol optimization, customizing scanning techniques based on the patients' clinical scenario and demographics. Supplemental strategies are postulated using more advanced post-processing techniques for achieving further dose improvements.

Expert opinion: The technologic offerings of CT are integral to modern medicine and its role will continue to evolve. Although, the estimated risks from low levels of radiation of a single CT exam are uncertain, it is prudent to minimize the dose from CT by applying common sense solutions and using other simple strategies as well as exploiting technologic innovations. These efforts will enable us to take advantage of all the clinical benefits of CT while minimizing the likelihood of harm to patients.

Introduction: Heart failure with preserved ejection fraction (HFPEF) is a common syndrome, accounting for about 50% of all patients with heart failure (HF). Morbidity and mortality are similar to patients with HF with reduced ejection fraction (HFREF), yet no effective treatment has been identified in randomized clinical trials.

Areas covered: This article provides an overview of the available literature regarding diagnosing established HFPEF and potential new therapeutic targets for the early diagnosis of HFPEF. Vascular dysfunction, ventricular-arterial coupling, oxidative stress, extracellular matrix regulation, chronotropic incompetence, pulmonary hypertension, exercise testing and biomarkers were taken into consideration next to conventional measurements of diastolic dysfunction.

Expert opinion: Measuring diastolic dysfunction in HFPEF is considered important in many patients. Nevertheless, today we know that other causes besides diastolic dysfunction are also involved in the pathophysiology of many HFPEF patients and need to be investigated in order to make a correct diagnosis. Therefore, further research is required to allow better and more specific diagnostic and treatment options to reduce the morbidity and mortality for this ever-expanding HF population.

Introduction: Biochemical diagnosis of acromegaly relies on measurement of insulin-like growth factor-1 (IGF-1) and growth hormone (GH). An elevated IGF-1 level above the age- and gender-specific normal range and nonsuppression of GH to oral glucose load to a nadir < 0.4 ng/ml in sensitive assays are currently considered diagnostic of acromegaly. Lack of normative data for both IGF-1 and GH across a wide range of populations and ethnicities, interassay and intraassay laboratory variability, pulsatility of GH secretion, and effects of medications and hormones may confound interpretation of these biochemical tests.

Areas covered: Clinical situations in which acromegaly should be suspected and/or investigated. Strengths and limitations of current IGF-1/GH assays are discussed. Clinical scenarios with discordant GH suppression test and IGF-1 levels and, briefly, acromegaly in pregnancy, prolactin-cosecreting tumors, familial acromegaly, and nonpituitary acromegaly are also discussed.

Expert opinion: Serum IGF-1 is the cornerstone and in most cases the stand-alone test in the diagnosis and follow-up in patients with acromegaly. Diagnosis depends on the accurate and reliable measurement of serum IGF-1. GH suppression testing is currently used in limited clinical setting. Standardization of IGF-1 assay and development of normative data across a wide population base are needed. Newer bioassays for IGF-1 hold promise for future.

Introduction: When using adequate wavelength illumination and high resolution recordings, Caucasian skin color appears uneven. The patterns of faint mosaic melanoderma (FMM) are diverse and possibly related to the risk of skin cancer development.

Areas covered: The current peer-reviewed publications about objective methods quantifying FMM are revisited. The images from the Visioscan® and Visioface® Quick devices are computerized in order to record the ultraviolet light-enhanced visualization (ULEV) and the color-enhanced visualization (CEV) of the skin. Previously published data regarding the FMM are gathered in 20 odd Caucasian women. Seven FMM patterns are distinguished. They appear expressed differently according to body regions, but the mean gray level appears more uniform.

Expert opinion: The combination of larger subclinical melanotic macules and ivory spots during early adulthood is apparently associated with an increased risk for non-melanoma skin cancers.

Biomarker research of psychiatric disorders is delayed by symptom pattern-related diagnostic categories that are only distantly associated with biological mechanisms. In neuropsychiatric disorders that have high heritability (schizophrenia, autism, Alzheimer's disease), genomic research led to significant genome-wide association study (GWAS) results by increasing the number of subjects in case-control studies, and thus provided new hypotheses regarding the aetiology of these disorders and possible targets for research of new treatment approaches. In contrast, in moderately heritable psychiatric disorders (anxiety disorders, unipolar major depression), the development of symptoms, in addition to risk genes, is more dependent on the presence of specific environmental risk factors. Thus, controlling for heterogeneity, and not simply increasing the number of subjects, is crucial for further significant psychiatric GWAS findings that warrant the collection of more detailed individual phenotypic data and information about relevant previous environmental exposures. Gene-gene interactions (epistasis) and intermediate phenotypes or psychiatric and somatic co-morbidities, by identifying similar cases within a diagnostic category, could further increase the generally weak effects of individual genes that limit their usefulness as biomarkers. In conclusion, we argue that methods that are suitable to identify biologically more homogeneous subgroups within a given psychiatric disorder are necessary to advance biomarker research.

Background: Women suspecting pregnancy need an accurate result when they conduct a home pregnancy test. A variety of tests are available from simple professional style strips to midstream tests with a digitally displayed result. However, it is not known whether all these formats can be used and read correctly by untrained women.

Objectives: The aim of this study is to evaluate usability and reading accuracy of home pregnancy test formats.

Methods: Female volunteers, 18 - 45 years (Manchester, UK) completed questionnaires on their home-use experience of six pregnancy tests (strip, cassette, midstream visual and digital formats). These volunteers then evaluated device results using hCG-urine standards at a study centre, thereafter completing a questionnaire and ranking evaluation.

Results: Data were available from 111 volunteers. Women preferred midstream test formats; > 70% scored branded midstream digital and easy-use visual tests as 1or 2 (7-point Likert score), compared with ∼ 30% for store-brand and branded midstream visual tests, and < 10% for cassette or strip tests. Many cassette tests (23%) failed to provide a result (4, ≤ 2% for strips, midstream, respectively). Volunteers disagreed with study co-ordinator reading of test results in 30 and 40% of cases for the cassette and strip test results, respectively, compared with < 3% when using midstream digital or easy-use visual tests. Volunteers preferred the branded midstream digital, followed by branded midstream easy-use and visual tests.

Conclusions: In this study, the branded midstream digital test was superior to other tests evaluated and fulfilled the criteria of being an easy-to-use and interpret test; strip and cassette tests showed poor performance in women's hands.

Before the 1980s, prostate cancer (PC) was considered a deadly disease. The mortality-incidence ratio showed that 1 out of each 2 - 3 PC patients died of this disease. On the other hand, autopsy studies have shown that latent PC is common in middle-aged men. The prostate-specific antigen (PSA), a glycoprotein produced by the epithelial cells of the prostate gland, received FDA's approval in 1986 for monitoring treatment response, and in 1994 as a screening aid for the diagnosis of PC. After the publication of two randomized trials on PC screening using the PSA test, it is generally accepted that systematic PSA-based screening, as compared to a clinical situation with virtually no screening, can reduce suffering from metastatic disease and PC mortality. However, what is also shown is that PSA-based screening coincides with a considerable amount of unnecessary testing and overdiagnosis. Should we abandon the use of the PSA test for the diagnosis of PC, or should we encourage PSA testing and make it freely available for all men at any time? Both the answers should be "No." What we must do is use the test as wisely as is currently possible and inform men, who want to be tested, in a balanced way about harms and potential benefits.

Introduction: The worldwide incidence of biliary tract carcinoma (BTC, tumours of the bile ducts and gall-bladder) continues to rise, with the only potentially curative treatment remaining surgical resection or transplantation, possible in only a minority of patients. Late presentation and a paucity of effective treatments mandate the development of techniques for early lesion detection.

Areas covered: This article reviews currently available biomarkers for the diagnosis and prognosis of BTC, as well as recently published studies describing novel serum, bile and urinary biomarkers.

Expert opinion: The incorporation of novel analysis techniques, such as digital image analysis and fluorescence in situ hybridization, into existing management algorithms enhances the accuracy of brush cytology taken at the time of therapeutic endoscopy. However, a key goal is the discovery of reliable non-invasive biomarkers with high sensitivity and specificity. Recent advances in gene sequencing and expression, clonal evolution and tumour heterogeneity in other cancers should advance understanding of BTC tumour biology and facilitate biomarker discovery.

Background: Little or no study has been done to compare the indices of 'nitrosative' and 'oxidative' stresses, especially in terms of correlation and the possible differential effects of the chelating agents.

Objective: This preliminary study investigated possible correlations between the indices of reactive nitrogen species (RNS) and reactive oxygen species (ROS) in blood, effect of anticoagulated-blood tubes, and impact of blood-clotting pathways.

Methods: Thirty blood samples from sheep were collected into ethylenediamine tetraacetic acid (EDTA) and citrate tubes at the Berrima Veterinary Laboratory using their standard protocol. Nitrosative and oxidative stress indices were then measured and correlation analyses performed.

Results: The ROS and RNS indices were weakly correlated (r > 0.2; p < 0.05) with each other from the EDTA sample, but not from citrated blood. None of the nitrosative or oxidative stress biomarkers was significantly associated with changes in the prothrombin time. The activated partial thromboplastin time showed statistically significant association with some oxidative stress indices (catalase and malondialdehyde), but with none of the nitrosative stress indices. Further, all measured parameters were higher in EDTA than in citrate blood (p < 0.0001).

Conclusion: The choice of anticoagulated blood tube could affect the measures of nitrosative stress indices and may impact on the potential correlations between nitrosative versus oxidative stress biomarkers. Perhaps the suggestion that EDTA is better than citrate for hematological anticoagulant studies should be considered for nitrosative and oxidative stress studies.