The effect of different analytical platforms and methods on the performance of population-specific adjusted calcium equation

Background A recent attempt to improve the diagnostic value of adjusted calcium addressed a primary care-specific adjusted calcium equation, but validated the new equation for Roche Cobas, BCG and NM-BAPTA methods only. In this study, we aim to validate a population-specific equation for other methods and platforms. Method We collected retrospective patient data-sets from 15 hospital laboratories using a range of commercially available analytical platforms and methods for calcium and albumin measurements. Raw data-sets were collected and filtered according to Payne’s criteria, and separate adjusted calcium equations were derived for hospitalized and primary care patients. Results Mean albumin and calcium results were significantly higher in primary care populations ( P < 0.0001). The prevalence of hypocalcaemia using adjusted calcium ranged between 6% and 44% for inpatient data-sets and was higher in users of BCG methods. The application of community-specific adjustment equation to primary care data-sets reduced the prevalence of hypocalcaemia (mean 1.7%, range 0.8–3.7%). Conclusion We demonstrated that the use of a community-specific calcium adjustment equation to a primary care population reduces both the percentage and the variation of hypocalcaemia between different laboratories.

A MULTI-CORE PARALLEL MOSAIC ALORITHM FOR MULTI-VIEW UAV IMAGES

As the spread of the error and accumulation often lead to distortion or failure of image mosaic during the multi-view UAV (Unmanned Aerial Vehicle) images stitching. In this paper, to solve the problem we propose a mosaic strategy to construct a mosaic ring and multi-level grouping parallel acceleration as an auxiliary. First, the input images will be divided into several groups, each group in the ring way to stitch. Then, use SIFT for matching, RANSAC to remove the wrong matching points. And then, calculate the perspective transformation matrix. Finally weaken the error by using the adjustment equation. All these steps run between different groups at the same time. By using real UAV images, the experiment results show that this method can effectively reduce the influence of accumulative error, improve the precision of mosaic and reduce the mosaic time by 60&amp;thinsp;%. The proposed method can be used as one of the effective ways to minimize the accumulative error.

A novel data processing method for sectional rail measurements to detect track irregularities in high-speed railways

Static track inspection methods record the position and direction data through track surveys completed by trolleys that survey a track based on a track control network. The track inspection points must be measured in sections to decrease the likelihood of measurement errors. Certain track inspection points will be measured twice by adjacent stations, and different results will be obtained because of the measurement errors. To improve the regularity of the track, inspection point data from the sectional measurements must be processed, and differences in the results for the same inspection points must be eliminated. Therefore, this paper proposes a novel method referred to as the regularity for processing sectional measurement data (RPSMD) method, which overcomes the disadvantages of the currently available methods of processing inspection points via track-surveying trolleys and also improves the processing of nonoverlapping and overlapping inspection points. The adjustment criterion states that the difference value for the same adjusted overlapping points should be zero, and this criterion can be used to obtain the adjustment equation for each station. Using the adjustment equation, all station points can be corrected and the total regularity of the track points can be guaranteed. According to precisely measured ballastless tracks and their calculated three-dimensional coordinates, the RPSMD method and other available methods are verified by an experimentally designed precise mechanical device. The experimental results show that the accuracy of the nonoverlapping points adjusted by the RPSMD method is improved, and the accuracy is obviously higher than that obtained by the other available methods. Also, the accuracy of the RPSMD-adjusted overlapping points is much higher than that of the nonadjusted points.

Validation of a locally derived serum calcium adjustment equation: relationship with total 25(OH) vitamin D and PTH levels

AimsMany clinical laboratories in the UK use a standard equation to adjust total calcium for albumin concentration. To assess the validity of this practice, we assessed the effect of the use of a traditional and locally derived calcium adjustment equation on parathyroid hormone (PTH) and 25(OH, hydroxy) vitamin D levels.MethodsSamples requested for calcium and albumin measurement over a 6 month period that met inclusion criteria were used to derive a calcium adjustment equation (n=60 941). The traditional and locally derived calcium adjustment equations were then applied to a second cohort of adult patients that underwent calcium measurement over a 1 year period (n=275 456). Patients were classified as hypocalcaemic, normocalcaemic or hypercalcaemic using a UK Pathology Harmony adjusted calcium reference interval (2.2–2.6 mmol/L).ResultsThe local calcium adjustment equation provided a 7.1-fold reduction in the prevalence of hypocalcaemia. Patients classified as hypocalcaemic using the locally derived equation had statistically significantly lower 25(OH) vitamin D and higher PTH levels. A 2.4-fold increase in the prevalence of hypercalcaemia was also observed using the new equation, but with no significant difference in 25(OH) vitamin D or PTH levels.ConclusionsA locally derived calcium adjustment equation reclassified the calcium status of 61 278 (22%) patients. Patients classified as hypocalcaemic by the locally derived equation had significantly lower 25(OH) vitamin D and significantly higher PTH values, providing evidence that use of this adjustment equation generates adjusted calcium results of greater clinical relevance. This study provides further and novel evidence that individual laboratories should determine local equations for adjusted calcium where possible.