A review of guidelines for evaluating a minor modification to a validated assay

Any modification to a validated assay must be evaluated in terms of the impact on the assay's performance characteristics and whether the assay remains fit for the intended purpose. The comparison is referred to as a 'method comparison', 'method comparability', 'method change', or 'comparative validation'. This review presents recommendations and examples of studies found in the current literature as a means of assessing minor modifications. In addition, the authors discuss common statistical approaches used for these comparisons.

Cardiometabolic risk in survivors of childhood cancer who received hematopoietic cell transplant (HCT)

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Background: Evidence suggests that survivors of childhood cancer are at increased risk for cardiovascular disease (CVD) and type 2 diabetes with even higher risk in those who received HCT. The purpose of this study was to compare the cardiometabolic risk factor profile in HCT patients and healthy sibling controls. Methods: Measures of insulin resistance (euglycemic hyperinsulinemic clamp adjusted for lean body mass [Mlbm], low Mlbm represents insulin resistance), fasting glucose, insulin, lipids, anthropometry, blood pressure (BP), and carotid artery compliance and distensibility (lower values represent arterial stiffness) were determined in 87 children and young adults (current age 27.3 yr, 57% male) who had received HCT for hematologic malignancy during childhood (mean age at HCT 11.8 yr) and 55 healthy sibling controls (current age=25.2 yr, 51% male). Linear regression models were used to evaluate risk factors between groups after adjusting for age, gender, pubertal stage, body mass index (BMI), and carotid lumen diameter (stiffness measures only). Results: Metabolic syndrome (ATP III criteria for adults, modified criteria for children) was present in 13 (14.9%) HCT survivors and 4 (7.3%) controls (p=0.19). Thirty-one (35.6%) survivors and 9 (16.4%) controls had two or more components of the metabolic syndrome (p=0.11). There were no differences between groups for BMI, waist circumference, percent body fat, or BP. HCT survivors had higher triglycerides, fasting glucose and insulin, lower HDL cholesterol, arterial distensibility, and were more insulin resistant (Table). Conclusions: HCT survivors have increased cardiometabolic risk factors independent of obesity suggesting that cancer itself and/or associated treatment exposures have a direct influence on CVD risk and that early screening and management of cardiometabolic risk factors should be considered in HCT survivors.

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No significant financial relationships to disclose.

Mapping genes for resistance to barley stripe rust (Puccinia striiformis f. sp. hordei)

Two genes conferring resistance to the barley stripe rust found in Mexico and South America, previously identified as race 24, were mapped to the M arms of barley chromosomes 7 and 4 in a doubled haploid population using molecular markers and the quantitative trait loci (QTL) mapping approach. The resistance gene on chromosome 7 had a major effect, accounting for 57% of the variation in disease severity. The resistance gene on chromosome 4 had a minor effect, accounting for 10% of the variation in trait expression. Two pairs of restriction fragment length polymorphism markers are being used to introgress the resistance genes to North American spring barley using molecular marker-assisted backcrossing.