### A. Definition of Terms Acute coronary syndrome (ACS)8 refers to a constellation of clinical symptoms caused by acute myocardial ischemia1,2. Owing to their higher risk for cardiac death or ischemic complications, patients with ACS must be identified among the estimated 8 million patients with nontraumatic chest symptoms presenting for emergency evaluation each year in the US3. In practice, the terms suspected or possible ACS are often used by medical personnel early in the process of evaluation to describe patients for whom the symptom complex is consistent with ACS but the diagnosis has not yet been conclusively established1. Patients with ACS are subdivided into 2 major categories based on the 12-lead electrocardiogram (ECG) at presentation (Fig. 1): those with new ST-segment elevation …

Doi: 10.1161/CIRCULATIONAHA.107.18288

Total tau (tTau) and phosphorylated 181P tau (pTau) are supportive diagnostic cerebrospinal fluid (CSF) biomarkers for Alzheimer's disease. Manual CSF tau assays are limited by lot-to-lot and between-laboratory variability and long incubation/turnaround times. Elecsys® Total-Tau CSF and Phospho-Tau (181P) CSF immunoassays were developed for fully automated cobas e analyzers, allowing broader access in clinical practice and trials. Analytical performance, reproducibility, method comparisons with commercially available assays, and lot-to-lot and platform comparability (cobas e 601/411) of the Elecsys® CSF assays were assessed. Tau distributions and concentration ranges were evaluated in CSF samples from two clinical cohorts. Both assays showed high sensitivity (limit of quantitation [LoQ]: 63 pg/mL [tTau]; 4 pg/mL [pTau]) and linearity over the measuring range (80-1300 pg/mL; 8-120 pg/mL), which covered the entire concentration range measured in clinical samples. Lot-to-lot and platform comparability demonstrated good consistency (Pearson's r: 0.998; 1.000). Multicenter evaluation coefficients of variation (CVs): repeatability, < 1.8%; intermediate precision, < 2.8%; between-laboratory variability, < 2.7% (both assays); and total reproducibility, < 6.7% (tTau) and < 4.7% (pTau). Elecsys® CSF assays demonstrated good correlation with commercially available tau assays. Elecsys® Total-Tau CSF and Phospho-Tau (181P) CSF assays demonstrate good analytical performance with clinically relevant measuring ranges; data support their use in clinical trials and practice.

OBJECTIVE: To develop methods for systematically reviewing evidence for identifying effective laboratory medicine (LM) practices associated with improved healthcare quality outcomes. RELEVANCE: Although many evidence-evaluation systems have been developed, none are designed to include and rate healthcare quality improvement studies to identify evidence-based practices that improve patient safety and LM quality. METHODS: Validated evidence-based medicine methods established by governmental agencies, the Guide to Community Preventive Services, and others were adapted for the LM field. Key methods modifications included (a) inclusion of quality improvement study designs; (b) mechanisms for inclusion of unpublished evidence, (c) combining of individual ratings of study quality, effect size, and relevance of outcome measures to evaluate consistency of practice evidence; and (d) deriving an overall strength rating to support evidence-based best practice recommendations. The methods follow the process steps of: ask; acquire; appraise; analyze; apply; and assess. Expert panels used the systematic evidence review results on practice effectiveness for improving healthcare quality outcomes consistent with the Institute of Medicine's healthcare quality aims (safe, timely, effective, equitable, efficient, and patient-centered). CONCLUSIONS: Adapting and developing methods from validated systems and applying them to systematically review and evaluate practices in LM by using published and unpublished studies is feasible. With these methods, evidence from quality improvement studies can be systematically synthesized and summarized to identify effective LM practices. Practical and scientifically validated demonstration of a positive impact on outcomes ensures that practitioners, policy makers, and decision makers at all levels have the evidence needed for improving healthcare quality and public health.