Reference intervals comparison of calculation methods and evaluation of procedures for merging reference measurements fromTwo US medical centers

Objectives: To analyze consistency of reference limits and widths of reference intervals (RIs) calculated by six procedures and evaluate a protocol for merging intrainstitutional reference data. Methods: The differences between reference limits were compared with "optimal" bias goals. Also, widths of the RIs were compared. RIs were calculated using Mayo-SAS quantile, EP Evaluator, and four International Federation of Clinical Chemistry and Laboratory Medicine methods: parametric and nonparametric (NP) with and without latent abnormal values exclusion (LAVE). Regression parameters from cotested samples were evaluated for harmonizing intrainstitutional reference data. Results: Mayo-SAS quintile, LAVE(-) NP, and EP Evaluator generated similar RIs, but these RIs often were wider than RIs from parametric procedures. LAVE procedures generated narrower RIs for nutritional and inflammatory markers. Transformation with regression parameters did not ensure homogeneity of merged data. Conclusions: Parametric methods are recommended when inappropriate values cannot be excluded. The nonparametric procedures may generate wider RIs. Data sets larger than 200 are recommended for robust estimates. Caution should be exercised when merging intrainstitutional data

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

Diagnostic laboratory standardization and validation of platelet transmission electron microscopy

<p>Platelet transmission electron microscopy (PTEM) is considered the gold standard test for assessing distinct ultrastructural abnormalities in inherited platelet disorders (IPDs). Nevertheless, PTEM remains mainly a research tool due to the lack of standardized procedures, a validated dense granule (DG) count reference range, and standardized image interpretation criteria. The aim of this study was to standardize and validate PTEM as a clinical laboratory test. Based on previously established methods, we optimized and standardized preanalytical, analytical, and postanalytical procedures for both whole mount (WM) and thin section (TS) PTEM. Mean number of DG/platelet (plt), percentage of plts without DG, platelet count (PC), mean platelet volume (MPV), immature platelet fraction (IPF), and plt light transmission aggregometry analyses were measured on blood samples from 113 healthy donors. Quantile regression was used to estimate the reference range for DG/plt, and linear regression was used to assess the association of DG/plt with other plt measurements. All PTEM procedures were standardized using commercially available materials and reagents. DG interpretation criteria were established based on previous publications and expert consensus, and resulted in improved operator agreement. Mean DG/plt was stable for 2 days after blood sample collection. The median within patient coefficient of variation for mean DG/plt was 22.2%; the mean DG/plt reference range (mid-95th %) was 1.2–4.0. Mean DG/plt was associated with IPF (<i>p </i>= .01, R² = 0.06) but not age, sex, PC, MPV, or plt maximum aggregation or primary slope of aggregation (<i>p </i>> .17, R² < 0.02). Baseline ultrastructural features were established for TS-PTEM. PTEM was validated using samples from patients with previously established diagnoses of IPDs. Standardization and validation of PTEM procedures and interpretation, and establishment of the normal mean DG/plt reference range and PTEM baseline ultrastructural features, will facilitate implementation of PTEM as a valid clinical laboratory test for evaluating ultrastructural abnormalities in IPDs.</p