Recommendations on the measurement and use of the alcohol consumption biomarker CDT. A position paper from the IFCC Working Group on CDT standardisation

Predicting Anabolic Androgenic Steroid Doping among Specialized Health Care Patients with Elastic Net Regression Reveals Potential Laboratory Variables for "Patient Biological Passport"

BACKGROUND

Recent years have brought significant development in athlete doping use detection with the implementation of the Athlete Biological Passport (ABP). The aim of this study was to explore if similar methods could also be used to detect non-medical use of anabolic androgenic steroids (AAS) among clinical patients. For this purpose, six elastic net regression models were trained in a sample of Finnish specialized health care male patients (N = 2918; no doping = 1911, AAS doping = 1007), using different approaches to longitudinal laboratory measurements as predictive variables. The laboratory data was retrieved from the Hospital District of Helsinki and Uusimaa (HUS) data lake, and doping use status was defined by patient disclosure, recorded in digital medical record free texts. Length of observation time (e.g., time between the first and last laboratory measurement) was used as weight. Model performance was tested with holdout cross-validation.

RESULTS

All the tested models showed promising discriminative ability. The best fit was achieved by using the existence of out-of-reference range measurements of 31 laboratory parameters as predictors of AAS doping, with test data area under the receiver operating characteristic curve (AUC) of 0.757 (95% CI 0.725-0.789).

CONCLUSIONS

The findings of this preliminary study suggest that AAS doping could be detected in clinical context using real-life longitudinal laboratory data. Further model development is encouraged, with added dimensions regarding the use of different AAS substances, length of doping use, and other background data that may further increase the diagnostic accuracy of these models.

Behind the scenes of EQA - characteristics, capabilities, benefits and assets of external quality assessment (EQA)

External quality assessment (EQA) enhances patient safety through the evaluation of the quality of laboratory-based and point of care testing. Regulatory agencies and accreditation organizations utilize the results and the laboratory's response to them as part of assessing the laboratory's fitness to practice. In addition, where EQA samples are commutable and the assigned value has been determined using reference measurement procedures (RMPs), EQA data contributes to the verification of metrological traceability of assays as part of the post-market surveillance of in vitro diagnostic (IVD) medical devices (IVD-MDs). More broadly, the scientific and medical communities use EQA data to demonstrate that medical laboratory examination procedures are fit for clinical purposes, to evaluate common reference intervals, and inclusion of data in clinical databases. Scientific groups, the IVD industry, reference laboratories and National Metrology Institutes can work with EQA providers to identify measurands, which should urgently be supported by the development of reference materials or methods. The ability of health systems to respond effectively to fast-evolving medical challenges, such as the Coronavirus Disease-19 (COVID-19) pandemic, is reliant on EQA to demonstrate confidence in the performance of new laboratory methods and testing services. EQA providers are uniquely positioned to assess the performance of IVD-MDs in addition to individual laboratories and testing sites. Although the primary focus of EQA providers remains the improvement of the performance of individual laboratories, there are many stakeholders who benefit from EQA performance data.

Phosphatidylethanol (B-PEth) and other direct and indirect biomarkers of alcohol consumption

When identifying, preventing and treating alcohol use disorder, a correct estimation of alcohol intake is essential. An objective marker is preferred as self-reported alcohol intake suffers from bias, and the use of alcohol biomarkers is increasing globally. An easy-to-use blood biomarker to correctly assess alcohol consumption is an invaluable asset in alcohol treatment strategies, as well as in alcohol research studies. The specific, cumulative, biomarker phosphatidylethanol, mirroring the past two weeks of consumption, has shown superiority over traditional biomarkers and is an attractive choice of proxy for alcohol intake.