First international descriptive and interventional survey for cholesterol and non-cholesterol sterol determination by gas- and liquid-chromatography-Urgent need for harmonisation of analytical methods.

Serum concentrations of lathosterol, the plant sterols campesterol and sitosterol and the cholesterol metabolite 5α-cholestanol are widely used as surrogate markers of cholesterol synthesis and absorption, respectively. Increasing numbers of laboratories utilize a broad spectrum of well-established and recently developed methods for the determination of cholesterol and non-cholesterol sterols (NCS). In order to evaluate the quality of these measurements and to identify possible sources of analytical errors our group initiated the first international survey for cholesterol and NCS. The cholesterol and NCS survey was structured as a two-part survey which took place in the years 2013 and 2014. The first survey part was designed as descriptive, providing information about the variation of reported results from different laboratories. A set of two lyophilized pooled sera (A and B) was sent to twenty laboratories specialized in chromatographic lipid analysis. The different sterols were quantified either by gas chromatography-flame ionization detection, gas chromatography- or liquid chromatography-mass selective detection. The participants were requested to determine cholesterol and NCS concentrations in the provided samples as part of their normal laboratory routine. The second part was designed as interventional survey. Twenty-two laboratories agreed to participate and received again two different lyophilized pooled sera (C and D). In contrast to the first international survey, each participant received standard stock solutions with defined concentrations of cholesterol and NCS. The participants were requested to use diluted calibration solutions from the provided standard stock solutions for quantification of cholesterol and NCS. In both surveys, each laboratory used its own internal standard (5α-cholestane, epicoprostanol or deuterium labelled sterols). Main outcome of the survey was, that unacceptably high interlaboratory variations for cholesterol and NCS concentrations are reported, even when the individual laboratories used the same calibration material. We discuss different sources of errors and recommend all laboratories analysing cholesterol and NCS to participate in regular quality control programs.

International descriptive and interventional survey for oxycholesterol determination by gas- and liquid-chromatographic methods.

Increasing numbers of laboratories develop new methods based on gas-liquid and high-performance liquid chromatography to determine serum concentrations of oxygenated cholesterol metabolites such as 7α-, 24(S)-, and 27-hydroxycholesterol. We initiated a first international descriptive oxycholesterol (OCS) survey in 2013 and a second interventional survey 2014 in order to compare levels of OCS reported by different laboratories and to define possible sources of analytical errors. In 2013 a set of two lyophilized serum pools (A and B) was sent to nine laboratories in different countries for OCS measurement utilizing their own standard stock solutions. In 2014 eleven laboratories were requested to determine OCS concentrations in lyophilized pooled sera (C and D) utilizing the same provided standard stock solutions of OCS. The participating laboratories submitted results obtained after capillary gas-liquid chromatography-mass selective detection with either epicoprostanol or deuterium labelled sterols as internal standards and high-performance liquid chromatography with mass selective detection and deuterated OCS as internal standard. Each participant received a clear overview of the results in form of Youden-Plots and basic statistical evaluation in its used unit. The coefficients of variation of the concentrations obtained by all laboratories using their individual methods were 58.5-73.3% (survey 1), 56.8-60.3% (survey 2); 36.2-35.8% (survey 1), 56.6-59.8, (survey 2); 61.1-197.7% (survey 1), 47.2-74.2% (survey 2) for 24(S)-, 27-, and 7α-hydroxycholesterol, respectively. We are surprised by the very great differences between the laboratories, even under conditions when the same standards were used. The values of OCS's must be evaluated in relation to the analytical technique used, the efficiency of the ample separation and the nature of the internal standard used. Quantification of the calibration solution and inappropriate internal standards could be identified as major causes for the high variance in the reported results from the different laboratories. A harmonisation of analytical standard methods is highly needed.

Connecting the dots: using 'big data' to build an efficient, integrated service line.

As seen in the case of musculoskeletal care, the broad steps hospitals and health systems should take to optimize service lines include: Understanding their market's demand for services. Guiding patients through integrated, patient-centric care. Taking patient engagement to the next level.

Development and validation of a cough and sputum assessment questionnaire.

Although cough and sputum production may impact patients' well being and functioning in COPD and chronic bronchitis, there is no validated instrument for cough and sputum symptoms and their impact on patients' daily activities. To fill that gap, we developed and validated a specific, multilingual Cough and Sputum Assessment Questionnaire (CASA-Q) that evaluates clinical symptoms and their impact on patients with COPD or chronic bronchitis. In a three-country validation study (n=671), there was adequate internal consistency (Cronbach's alphas, 0.80-0.91) and test-retest reliability (correlation coefficients>0.70) for the CASA-Q. The cough impact and sputum impact domains correlated with the SGRQ impact domain and SGRQ total score, as did the cough impact domain with the SF-36 social functioning domain. The cough symptom and sputum symptom domains correlated with sputum wet weight (p<0.05; r=-0.56), but not with cough recordings. The mean CASA-Q cough symptom and sputum symptom domain scores indicated responsiveness towards both worse and improved symptoms, whereas the impact domains scored already in the upper third of the scale range, indicating the need for further improvement of its properties. Differences in the CASA-Q domain scores by smoking status (current vs. former smokers) were highest for cough symptoms and lowest for sputum impact. These data indicate that the CASA-Q may be a useful measure of cough and sputum production, and their impact in patients with COPD and/or chronic bronchitis. Further validation will need to assess the responsiveness of the CASA-Q to changes in symptoms.