Pre-processing stability of routine clinical chemistry analytes in a clotting tube; investigating the (un)suitability for at-home sample collection.

Background: There is a growing interest in self-collection of blood for clinical applications. Next to allowing patients to self-sample blood, adequate sample stability of the analyte is essential to provide an accurate and reliable test result. This is particularly important for self-collected blood, as the transport of the sample to the clinical laboratory will generally require significantly more time than routine blood samples collected by healthcare professionals, and under less controlled circumstances.

External quality assessment-based tumor marker harmonization simulation; insights in achievable harmonization for CA 15-3 and CEA.

Objectives: CA 15-3 and CEA are tumor markers used in routine clinical care for breast cancer and colorectal cancer, among others. Current measurement procedures (MP) for these tumor markers are considered to be insufficiently harmonized. This study investigated the achievable harmonization for CA 15-3 and CEA by using an simulation of external quality assessment (EQA) data from multiple EQA programs using patient-pool based samples.

Quality control in the Netherlands; todays practices and starting points for guidance and future research.

Objectives: Adequate analytical quality of reported results is primarily ensured by performing internal quality control (iQC). Currently, several different iQC practices are in use. As a prelude to the revision of a Dutch guidance document on analytical QC, a questionnaire was sent out to gain insights in the applied practices and the need for guidance.

An LC-MS/MS-based method for the simultaneous quantification of melatonin, cortisol and cortisone in saliva.

Disturbances in the diurnal pattern are associated with several clinical and psychological conditions, including depression and fatigue. Salivary sampling for melatonin, cortisol and cortisone provides a non-invasive method for frequent sampling and obtaining biochemical insight into the diurnal pattern of individuals. Therefore, a new liquid chromatography-tandem mass spectrometry-based method for the measurement of salivary melatonin, cortisol and cortisone was developed and validated.

Investigating the Current Harmonization Status of Tumor Markers Using Global External Quality Assessment Programs: A Feasibility Study.

Background: The harmonization status of most tumor markers (TMs) is unknown. We report a feasibility study performed to determine whether external quality assessment (EQA) programs can be used to obtain insights into the current harmonization status of the tumor markers α-fetoprotein (AFP), prostate specific antigen (PSA), carcinoembryonic antigen (CEA), cancer antigen (CA)125, CA15-3 and CA19-9.

Methods: EQA sample results provided by 6 EQA providers (INSTAND [Germany], Korean Association of External Quality Assessment Service [KEQAS, South Korea], National Center for Clinical Laboratories [NCCL, China], United Kingdom National External Quality Assessment Service [UK NEQAS, United Kingdom], Stichting Kwaliteitsbewaking Medische Laboratoriumdiagnostiek [SKML, the Netherlands], and the Royal College of Pathologists of Australasia Quality Assurance Programs [RCPAQAP, Australia]) between 2020 and 2021 were used.

Advances in clinical chemistry patient-based real-time quality control (PBRTQC).

Patient-Based Real-Time Quality Control involves monitoring an assay using patient samples rather than external material. If the patient population does not change, then a shift in the long-term assay population results represents the introduction of a change in the assay. The advantages of this approach are that the sample(s) are commutable, it is inexpensive, the rules are simple to interpret and there is virtually continuous monitoring of the assay.

Comparing modeling strategies combining changes in multiple serum tumor biomarkers for early prediction of immunotherapy non-response in non-small cell lung cancer.

Background: Patients treated with immune checkpoint inhibitors (ICI) are at risk of adverse events (AEs) even though not all patients will benefit. Serum tumor markers (STMs) are known to reflect tumor activity and might therefore be useful to predict response, guide treatment decisions and thereby prevent AEs.

Objective: This study aims to compare a range of prediction methods to predict non-response using multiple sequentially measured STMs.

Self-sampling of blood using a topper and pediatric tubes; a prospective feasibility study for PSA analysis using 120 prostate cancer patients.

Objectives: Self-collection of blood for diagnostic purposes by blood collection assist devices (BCAD) has gained a lot of momentum. Nonetheless, there are a lack of studies demonstrating the feasibility and reliability of self-collecting capillary blood for routine (immuno)chemistry testing. In this study we describe the topper technology together with pediatric tubes to enable self-collection of blood and investigated its feasibility for PSA testing by prostate cancer patients.

Pre-analytical stability of the CEA, CYFRA 21.1, NSE, CA125 and HE4 tumor markers.

Background: For lung cancer, circulating tumor markers (TM) are available to guide clinical treatment decisions. To ensure adequate accuracy, pre-analytical instabilities need to be known and addressed in the pre-analytical laboratory protocols.

Objective: This study investigates the pre-analytical stability of CA125, CEA, CYFRA 21.

Clinical value of preoperative serum tumor markers CEA, CA19-9, CA125, and CA15-3 in surgically treated urachal cancer.

Introduction: Urachal adenocarcinoma (UrAC) is a very rare malignancy with a poor prognosis. The role of preoperative serum tumor markers (STMs) in UrAC is unknown. The aim of this study was to assess the clinical value of elevated STMs including carcinoembryonic antigen (CEA), cancer antigen 19-9 (CA19-9), cancer antigen 125 (CA125), and cancer antigen 15-3 (CA15-3) in surgically treated UrAC, and to evaluate their prognostic significance.

Clinical perspectives on serum tumor marker use in predicting prognosis and treatment response in advanced non-small cell lung cancer.

The optimal positioning and usage of serum tumor markers (STMs) in advanced non-small cell lung cancer (NSCLC) care is still unclear. This review aimed to provide an overview of the potential use and value of STMs in routine advanced NSCLC care for the prediction of prognosis and treatment response. Radiological imaging and clinical symptoms have shown not to capture a patient's entire disease status in daily clinical practice.

Current Routine Testosterone Immunoassays Are Unsuitable for Lowering the General Castration Cutoff Recommendation to <0.7 nmol/l (20 ng/dl).

Unlabelled: Testosterone measurements are essential in the management of patients with prostate cancer undergoing castration and androgen deprivation therapy. There has been an ongoing discussion on the testosterone castration cutoff (TCC), with the primary focus on large cohort studies in which the testosterone measurement system was not specified or studies that used individual testosterone measurement systems. Here we present a post hoc analysis of a study comparing testosterone measurement systems in a cohort of 120 castrated patients with prostate cancer.

Serum testosterone measured by liquid chromatography-tandem mass spectrometry is an independent predictor of response to castration in metastatic hormone-sensitive prostate cancer.

Background: Although testosterone levels have been associated with progression-free survival (PFS) in metastatic hormone-sensitive prostate cancer (mHSPC) patients, this has primarily been investigated using inaccurate immunoassays (IA). Here, we investigated whether castrate testosterone levels determined by a liquid chromatography-tandem mass spectrometry (LC-MS/MS) assay is an independent risk factor for treatment response in mHSPC.

Methods: In total, 106 mHSPC patients treated with luteinizing-hormone releasing-hormone (LHRH) agonists were retrospectively analyzed between March 2018 and August 2021.

Predictive value of low testosterone concentrations during and prior to enzalutamide treatment in metastatic castration-resistant prostate cancer.

Background: Enzalutamide is an effective treatment for metastatic castration-resistant prostate cancer (mCRPC) patients. However, variances in responses are observed and there is a need for biomarkers predicting treatment outcome and selection. In this study, we aimed to explore the predictive value of testosterone for first-line enzalutamide treatment of mCRPC.

Modeling strategies to analyse longitudinal biomarker data: An illustration on predicting immunotherapy non-response in non-small cell lung cancer.

Serum tumor markers acquired through a blood draw are known to reflect tumor activity. Their non-invasive nature allows for more frequent testing compared to traditional imaging methods used for response evaluations. Our study aims to compare nine prediction methods to accurately, and with a low false positive rate, predict progressive disease despite treatment (i.

Moving average quality control of routine chemistry and hematology parameters - a toolbox for implementation.

Objectives: Moving average quality control (MA QC) is a patient-based real-time quality control system. Advantages compared to conventional periodic internal quality control (IQC) include absence of commutability problems and continuous monitoring of performance. We implemented MA QC for multiple routine hematology and chemistry parameters.

Testosterone analysis in castrated prostate cancer patients: suitability of the castration cut-off and analytical accuracy of the present-day clinical immunoassays.

Objectives: Testosterone testing is relevant for evaluating castration adequacy and diagnosis of castration-resistant prostate cancer (PCa). However, the recommended testosterone cut-off of 1.7 nmol/L (50 ng/dL) to define adequate castration is based on consensus and not validated for the automated immunoassays (AIA) used in today's medical laboratories.

Technical quality assurance and quality control for medical laboratories: a review and proposal of a new concept to obtain integrated and validated QA/QC plans.

Technical quality assurance (QA) and quality control (QA/QC) are important activities within medical laboratories to ensure the adequate quality of obtained test results. QA/QC tools available at medical laboratories include external QC and internal QC, patient-based real-time quality control (PBRTQC) tools such as moving average quality control (MAQC), limit checks, delta checks, and multivariate checks, and finally, analyzer flagging. Recently, for PBRTQC tools, new optimization and validation methods based on error detection simulation have been developed to obtain laboratory-specific insights into PBRTQC error detection.

Testosterone analysis in prostate cancer patients.

Testosterone is an essential steroid hormone associated with a wide variety of biological processes in humans. In prostate cancer, androgen signaling is an important driver of tumor cell growth. Depletion of gonadal testosterone, achieved by surgical or chemical castration, prevents androgenic signaling and temporally reduces, stops or reverses tumor growth before inevitable progression to castration-resistant prostate cancer occurs.