Gender-partitioned patient medians of serum albumin requested by general practitioners for the assessment of analytical stability

AbstractBackground:Recently, the use of separate gender-partitioned patient medians of serum sodium has revealed potential for monitoring analytical stability within the optimum analytical performance specifications for laboratory medicine. The serum albumin concentration depends on whether a patient is sitting or recumbent during phlebotomy. We therefore investigated only examinations requested by general practitioners (GPs) to provide data from sitting patients.Methods:Weekly and monthly patient medians of serum albumin requested by GP for both male and female patients were calculated from the raw data obtained from three analysers in the hospital laboratory on examination of samples from those &gt;18 years. The half-range of medians were applied as an estimate of the maximum bias. Further, the ratios between the two medians were calculated (females/males).Results:The medians for male and female patients were closely related despite considerable variation due to the current analytical variation. This relationship was confirmed by the calculated half-range for the monthly ratio between the genders of 0.44%, which surpasses the optimum analytical performance specification for bias of serum albumin (0.72%). The weekly ratio had a half-range of 1.83%, which surpasses the minimum analytical performance specifications of 2.15%.Conclusions:Monthly gender-partitioned patient medians of serum albumin are useful for monitoring of long-term analytical stability, where the gender medians are two independent estimates of changes in (delta) bias: only results requested by GP are of value in this application to ensure that all patients are sitting during phlebotomy.</jats:sec

Separate patient serum sodium medians from males and females provide independent information on analytical bias

AbstractBackground:During monitoring of monthly medians of results from patients undertaken to assess analytical stability in routine laboratory performance, the medians for serum sodium for male and female patients were found to be significantly related.Methods:Daily, weekly and monthly patient medians of serum sodium for both male and female patients were calculated from results obtained on samples from the population &gt;18 years on three analysers in the hospital laboratory. The half-range of medians was applied as an estimate of the maximum bias. Further, the ratios between the two medians were calculated.Results:The medians of both genders demonstrated dispersions over time, but they were closely connected in like patterns, which were confirmed by the half-range of the ratios of medians for males and females that varied from 0.36% for daily, 0.14% for weekly and 0.036% for monthly ratios over all instruments.Conclusions:The tight relationship between the gender medians for serum sodium is only possible when raw laboratory data are used for calculation. The two patient medians can be used to confirm both and are useful as independent estimates of analytical bias during constant calibration periods. In contrast to the gender combined median, the estimate of analytical bias can be confirmed further by calculation of the ratios of medians for males and females.</jats:sec

Participation in introductory APIB training at the Colorado NIDCAP Center-Report on the training and its applicability to future studies-

本研修の目的は,新生児・早産児行動評価(Assessment of Term and Preterm Infant Behavior:APIB 1))を研究に活用するため,その具体的な方法を学ぶことであった.今回,国際NIDCAP®連盟(Newborn Individualized Developmental Care and Assessment Program FederationInternational:NFI)が認定する公式のトレーニング施設,Colorado NIDCAPセンターにおいて,2013年9月7日～8日の2日間,APIBの導入研修に参加する機会を得た.NFIは米国マサチューセッツ州ボストンに本部を置き,北米,南米,ヨーロッパに20のトレーニング施設を認定し,包括的で質の高いトレーニングとコンサルテーションの機会を提供している.APIBは,正期産児を対象とする新生児行動評価(Neonatal Behavioral Assessment Scale:NBAS 2))を,早産児と発達上のリスクを持つ新生児に適合するように開発された評価法であり,新生児と観察者の相互作用を通して,中枢神経系の組織化の状態と受け入れられる刺激を評価し,発達の評価や発達支援の方策を考案するために用いられている.APIBを研究に活用する際は,評価者としての認定が必要であり,トレーニングは「準備の段階」「導入トレーニング」「自主トレーニングおよび指導者との調整(中間評価)」「信頼性の評価」の4段階からなる.今回参加した導入研修では,APIBの基盤となる理論と実際の評価法を学び,評価の進め方とスコア化の基準を理解するとともに,早産児の現在の状態と受け入れられる刺激を評価することの重要性を知ることができた.本稿では,研修内容および今後の研究への活用性について報告する

Analytical performance specifications for changes in assay bias (Δbias) for data with logarithmic distributions as assessed by effects on reference change values

Background The distributions of within-subject biological variation are usually described as coefficients of variation, as are analytical performance specifications for bias, imprecision and other characteristics. Estimation of specifications required for reference change values is traditionally done using relationship between the batch-related changes during routine performance, described as Δbias, and the coefficients of variation for analytical imprecision (CVA): the original theory is based on standard deviations or coefficients of variation calculated as if distributions were Gaussian. Methods The distribution of between-subject biological variation can generally be described as log-Gaussian. Moreover, recent analyses of within-subject biological variation suggest that many measurands have log-Gaussian distributions. In consequence, we generated a model for the estimation of analytical performance specifications for reference change value, with combination of Δbias and CVA based on log-Gaussian distributions of CVI as natural logarithms. The model was tested using plasma prolactin and glucose as examples. Results Analytical performance specifications for reference change value generated using the new model based on log-Gaussian distributions were practically identical with the traditional model based on Gaussian distributions. Conclusion The traditional and simple to apply model used to generate analytical performance specifications for reference change value, based on the use of coefficients of variation and assuming Gaussian distributions for both CVI and CVA, is generally useful. </jats:sec