Sample preparation strategies for the determination of psychoactive substances in biological fluids.

This review focuses on the existing analytical procedures for the determination of new psychoactive substances (NPS) in biological fluids by chromatographic methods. Direct analysis of samples is scarcely employed and most proposed methodologies include a sample pre-treatment in order to remove matrix interferents and, in some cases, pre-concentrate extracts. Current extraction methods for NPS determination in plasma/serum, urine, and oral fluids have been widely discussed, such as liquid-liquid, solid-phase, and micro extraction approaches, highlighting the advantages and drawbacks of the proposed extraction methodologies. Regarding microextraction approaches, techniques like microextraction by packed sorbent, solid-phase microextraction, miniaturized solid phase extraction, and dispersive liquid-liquid extraction have been proposed for NPS determination in biological fluids with reliable analytical results.

Biomarkers of Alzheimer Disease.

BACKGROUND: Alzheimer disease (AD) was once a clinical diagnosis confirmed by postmortem autopsy. Today, with the development of AD biomarkers, laboratory assays to detect AD pathology are able to complement clinical diagnosis in symptomatic individuals with uncertain diagnosis. A variety of commercially available assays are performed as laboratory-developed tests, and many more are in development for both clinical and research purposes. CONTENT: The role of laboratory medicine in diagnosing and managing AD is expanding; thus, it is important for laboratory professionals and ordering physicians to understand the strengths and limitations of both existing and emerging AD biomarker assays. In this review, we will provide an overview of the diagnosis of AD, discuss existing laboratory assays for AD and their recommended use, and examine the clinical performance of emerging AD biomarkers. SUMMARY: The field of AD biomarker discovery and assay development is rapidly evolving, with recent studies promising to improve both the diagnosis of symptomatic individuals and enrollment and monitoring of asymptomatic individuals in research studies. However, care must be taken to ensure proper use and interpretation of these assays. For clinical purposes, these assays are meant to aid in diagnosis but are not themselves diagnostic. For individuals without symptoms, AD biomarker tests are still only appropriate for research purposes. Additionally, there are analytical challenges that require careful attention, especially for longitudinal use of AD tests.

Detection of Alzheimer Disease Pathology in Patients Using Biochemical Biomarkers: Prospects and Challenges for Use in Clinical Practice.

BACKGROUND: Thirty-four years ago, amyloid-ß 1-42 peptide was identified in amyloid plaques from brain tissue obtained from patients with Alzheimer disease (AD) and Down syndrome. This finding led to development of immunoassays for this marker of amyloid plaque burden in cerebrospinal fluid (CSF) approximately 10 years later. Subsequently, research immunoassays were developed for total τ protein and τ phosphorylated at the threonine 181 position. Subsequent studies documented the clinical utility of these biomarkers of amyloid plaque burden or τ tangle pathology in cohorts of living patients. CONTENT: We describe the following: (a) clinical utility of AD biomarkers; (b) measurement challenges, including development of mass spectrometry-based reference methods and automated immunoassays; (c) development of "appropriate use criteria" (AUC) guidelines for safe/appropriate use of CSF testing for diagnosis of AD developed by neurologists, a neuroethicist, and laboratorians; (d) a framework, sponsored by the National Institute of Aging-Alzheimer's Association (NIA-AA), that defines AD on the basis of CSF and imaging methods for detecting amyloid plaque burden, τ tangle pathology, and neurodegeneration. This framework's purpose was investigative but has important implications for future clinical practice; (e) recognition of copathologies in AD patients and challenges for developing methods to detect these in living patients. SUMMARY: The field can expect availability of validated research tools for detection of AD pathology that support clinical treatment trials of disease-modifying agents and, ultimately, use in clinical practice. Validated methods are becoming available for CSF testing; emergence of validated methods for AD biomarkers in plasma can be expected in the next few years.

A Laboratory Diagnostic Approach to Hepatobiliary Disease in Small Animals.

Routine biochemical tests generally include serum enzymes, proteins, and other markers useful for identifying hepatobiliary disease in dogs and cats. Obtaining results outside the reference intervals can occur with direct hepatocellular injury, enzyme induction by hepatocytes or biliary epithelium, or decreased hepatic function. However, detection of biochemical abnormalities does not necessarily indicate clinically significant disease. For a comprehensive approach to detection and treatment of hepatobiliary disease, the laboratory results must be correlated with the history and physical examination findings, diagnostic imaging results, and other assays.

Clinical Approach to Advanced Renal Function Testing in Dogs and Cats.

Serum creatinine concentration is insensitive for detecting kidney injury and does not assist in differentiation between glomerular versus tubular damage. Advanced renal function tests, including glomerular filtration rate testing, determining fractional excretion of electrolytes, and assay of urine biomarkers, may allow earlier detection of reduced renal function mass, differentiation of renal from non-renal causes of azotemia, and assist with localization of damage. This article reviews the principles, indications, and limitations of these tests and describes their use in sample clinical scenarios.

Diagnosis of Small Intestinal Disorders in Dogs and Cats.

Laboratory tests are an important part of the workup of small intestinal diseases in dogs and cats. Especially in chronic cases, when extragastrointestinal causes need to be ruled out, it is important to adhere to a systematic workup. This article details the newest available data on tests to aid this diagnostic process. Once the diagnosis of a chronic enteropathy is made, there are many laboratory tests that can help in monitoring the disease and providing prognostic information. Several new tests being evaluated for clinical usefulness are discussed.

Practical Interpretation and Application of Exocrine Pancreatic Testing in Small Animals.

The pancreas remains a difficult organ to evaluate using laboratory methods alone. No single laboratory test is diagnostic of pancreatitis (chronic or acute) without other diagnostic modalities concurring with the diagnosis or ruling out other diseases. The diagnosis of pancreatitis is particularly difficult in cats, and pancreatitis often occurs with other diseases. The use of pancreatic cytology may be useful in diagnosing both inflammation and neoplasia. Exocrine pancreatic insufficiency (EPI) can be relatively easily diagnosed when clinically manifested by the measurement of trypsinlike immunoreactivity. Diagnosis is more difficult when EPI is subclinical.

Trends in cardiac biomarker testing in China for patients with acute myocardial infarction, 2001 to 2011: China PEACE-retrospective AMI study.

OBJECTIVES: To describe trends in the availability of biomarker testing in Chinese hospitals and how practice complies with established standards for the diagnosis of acute myocardial infarction (AMI). BACKGROUND: Cardiac biomarker testing is standard in high-income countries, but little is known about the availability and use of cardiac biomarker testing in low- and middle-income countries (LMICs) such as China. METHODS: Based on a nationally representative sample of Chinese hospitals in 2001, 2006 and 2011, we describe the temporal trends and regional differences in the hospital capability and rates of use of cardiac biomarker testing, as well as the variation in use across hospitals with testing capability, for patients labeled with the diagnosis of AMI. RESULTS: We sampled 175 hospitals (162 participated in the study) and 18,631 AMI admissions. 14,370 patients were included in analysis of biomarker use. The proportion of hospitals with biomarker testing capability was 57.4% in 2001 (25.0% troponin and 32.4% creatine kinase MB fraction (CK-MB) only) and 96.3% (81.4% troponin and 14.9% CK-MB only) in 2011. The proportion of hospitals with troponin testing capability in 2011 was significantly higher in urban compared with rural hospitals (96.8% vs. 71.4%, p< 0.001). In 2011, only 55.9% of hospitals with troponin testing capability (71 out of 127 hospitals) used the assay for more than 80% of their patients with AMI. Among hospitals with either biomarker testing capability, there was marked variation in use in both rural (from 7.1% to 100.0% of patients) and urban hospitals (from 57.9% to 100.0% of patients). In 2011, 36.1% of the patients with AMI did not have troponin tested and 4.9% did not have either biomarker measured. CONCLUSIONS: The recommended biomarker tests for AMI diagnosis are not universally available and the testing is not consistently applied when it is available in China. TRIAL REGISTRATION: ClinicalTrials.gov NCT01624883.

The traditions and risks of fasting for lipid profiles in patients with diabetes.

Fasting overnight has been traditionally recommended by clinicians when ordering laboratory tests for lipid profiles for the purposes of health screening or monitoring of the effects of lipid-lowering medications. Patients with diabetes are tested for lipid profiles at least annually. This deeply rooted tradition of fasting for lipid testing has recently been challenged. Several studies have shown little benefit obtained by testing lipids in fasting compared with postprandial states. Furthermore, recent studies have shown the importance of postprandial lipid spikes in the pathogenesis of cardiovascular disease. At the same time, recent reports have alerted the medical community to the risk of hypoglycemia in patients with diabetes on antidiabetic medications (particularly insulin and sulfonylureas) who are asked to fast for lab tests. This article reviews the literature on these emerging issues in lipid testing in patients with diabetes, and offers recommendations for lipid testing in these patients in view of these emerging discussions.

Sixty-five years since the New York heat wave: advances in sweat testing for cystic fibrosis.

The sweat test remains important as a diagnostic test for cystic fibrosis (CF) and has contributed greatly to our understanding of CF as a disease of epithelial electrolyte transport. The standardization of the sweat test, by Gibson and Cooke [Gibson and Cooke (1959) Pediatrics 1959;23:5], followed observations of excessive dehydration amongst patients with CF and confirmed the utility as a diagnostic test. Quantitative pilocarpine iontophoresis remains the gold standard for sweat induction, but there are a number of collection and analytical methods. The pathophysiology of electrolyte transport in sweat was described by Quinton [Quinton (1983) Nature 1983;301:421-422], and this complemented the developments in genetics that discovered the cystic fibrosis transmembrane conductance regulator (CFTR), an epithelial-based electrolyte transport protein. Knowledge of CF has since increased rapidly and further developments in sweat testing include: new collection methods, further standardization of the technique with international recommendations and age related reference intervals. More recently, sweat chloride values have been used as proof of effect for the new drugs that activate CFTR. However, there remain issues with adherence to sweat test guidelines in many countries and there are gaps in our knowledge, including reference intervals for some age groups and stability of sweat samples in transport. Furthermore, modern methods of elemental quantification need to be explored as alternatives to the original analytical methods for sweat electrolyte measurement. The purpose of this review is therefore to describe the development of the sweat test and consider future directions.

C-reactive protein and erythrocyte sedimentation rate discordance: frequency and causes in adults.

C-reactive protein (CRP) levels and the erythrocyte sedimentation rate (ESR) are widely used tests of inflammation that sometimes show opposite results. We performed a retrospective cohort study to clarify the frequency and causes of CRP/ESR discordance in adults. Between January and December of 2011, the laboratories of Texas Health Presbyterian Hospital performed 2150 paired CRP/ESR measurements in 1753 patients, 1731 of whom were nonpregnant adults aged ≥ 18 years. Initial CRP and ESR results for each patient were divided into quartiles. CRP/ESR discordance, predefined as results differing by 2 or 3 quartiles, occurred in 212 patients (12%), 105 of whom had high CRP/low ESR discordance (6%) and 107 of whom had high ESR/low CRP discordance (6%). The 212 patients in the CRP/ESR-discordant group (128 women and 84 men) were subdivided into 1 of 6 diagnostic categories, and the causes of discordances were compared. The high CRP/low ESR-discordant group had more patients with infections than the high ESR/low CRP-discordant group (P = 0.001), particularly infections in the urinary tract (P = 0.03), gastrointestinal tract (P = 0.001), lungs (P = 0.005), and bloodstream (P = 0.03). However, they had fewer bone and joint infections than the high ESR/low CRP-discordant group (P = 0.001). Connective tissue diseases, such as systemic lupus erythematosus, were less common in the high CRP/low ESR-discordant group than in the high ESR/low CRP-discordant group (P = 0.001). Ischemic strokes or transient ischemic attacks almost invariably occurred in the high ESR/low CRP-discordant group (P = 0.001), whereas myocardial infarction or venous thromboembolism was limited to the high CRP/low ESR-discordant group (P = 0.001). Our findings provide information to physicians who order these 2 tests together and receive discordant results, which occurs in approximately 1 in 8 patients.

From challenges to solutions. European Bioanalysis Forum 3rd Annual Open Symposium, Hesperia Towers, Barcelona, Spain, 1-3 December 2010.

The European Bioanalysis Forum is a bioanalytical nonprofit organization comprised of European pharmaceutical companies (27 members to date) and currently expanding to include CROs as well. The European Bioanalysis Forum provides a broad European bioanalytical network for the discussion of scientific, technological and regulatory topics of bioanalytical interest. The 3rd Annual Open Symposium was again much anticipated after the two previous successful meetings. The symposium included sessions on thinking outside the 'commodity' box, bioanalytical challenges with blood, global harmonization, assay platforms, dried blood spots, immunogenicity, matrix effects, anomalous results, biomarkers and two plenary technology sessions hosted by the Platinum sponsors. Experts and key opinion leaders were invited as guest speakers. A total of 424 delegates registered from 113 companies representing a large percentage of the European bioanalytical community. In addition to 48 oral presentations, 88 posters were presented and there was a vendor exposition of 40 companies.

Frequency and determinants of lipid testing in ischemic stroke and transient ischemic attack: findings from get with the guidelines-stroke.

BACKGROUND AND PURPOSE: National guidelines recommend lipid testing for all patients with ischemic stroke and transient ischemic attack. This study examined the frequency and predictors for in-hospital low-density lipoprotein testing using data from a nationwide stroke registry. METHODS: Between 2003 and 2008, Get With The Guideline-Stroke (GWTG-Stroke) hospitals (n=981) contributed 479 284 consecutive ischemic stroke or transient ischemic attack admissions. Logistic regression models were used to determine patient and hospital characteristics associated with lipid testing. RESULTS: Frequency of LDL measurement increased from 54.3% in 2003 to 81.9% in 2008 (P<0.001), the adjusted OR for LDL measurement was 1.23 per additional calendar year (95% CI, 1.18 to 1.29; P<0.001). The frequency of LDL measurement also increased with longer hospital program participation; the adjusted OR was 1.17 per additional year of GWTG-Stroke participation (95% CI, 1.12 to 1.23; P<0.001). LDL measurement was lower in women, nonsmokers, those with atrial fibrillation, those with a history of stroke or transient ischemic attack, and in those with transient ischemic attack (versus ischemic stroke; all P<0.001). LDL >or=100 mg/dL was seen in 52.1% of those tested, including in 35.5% of patients already prescribed lipid-lowering therapy before admission. CONCLUSIONS: Rates of LDL measurement in hospitalized patients with ischemic stroke and transient ischemic attack have improved dramatically in this large quality improvement program, although disparities in testing still exist. Testing frequently revealed an LDL level that could prompt a change in clinical management.

Aseguramiento de la calidad: gestión funcional de la informática del laboratorio de análisis clínicos / Insurance of the quality: functional management of the laboratory informatics of clinical analyses

Atento a las normas internacionales para la acreditación de los laboratorios clínicos habíamos propuesto, para el mediano plazo, establecer dos objetivos para nuestro laboratorio: implantar un Sistema de Gestión de la Calidad (SGC) y dotar al mismo de la informática apropiada, con vistas a la futura acreditación del servicio. En ocasión de la implantación del Sistema Informático del laboratorio se establecieron los siguientes estándares: Diseño de un protocolo único que abarca todas las secciones del laboratorio, identificación unívoca de pacientes por código universal, reducción del tiempo de espera de turnos y de atención, unificación de reportes, acceso a la trazabilidad de todos los procesos y a la información y reducción de costos por la detección temprana de errores. Paralelamente se capacitó al recurso humano para el desarrollo y utilización del Sistema Informático por medio de reuniones con todas las áreas del laboratorio. Se expusieron y analizaron los beneficios y la factibilidad operativa, a la vez que se evaluaron los indicadores pre-mejora. Para efectuar el diagnóstico de situación describimos los procesos del laboratorio con todos sus procedimientos administrativos pre-analíticos, analíticos y post-analíticos y luego de planificar la mejora, pusimos en marcha el plan operativo. Se analizaron 4.024 protocolos durante cuatro semanas. A los 20 días hábiles de la implementación monitoreamos los indicadores post-mejora, cuya disminución en un tiempo tan corto permite afirmar que el proceso está bien encaminado. La experiencia de esta mejora es el resultado de un ambicioso proyecto que refleja la producción y dificultades de un laboratorio de atención asistencial que aporta datos del conjunto de los sectores y muestra la visión del grupo de dirección del laboratorio a través de la actividad del servicio.