Comparison of three different protocols for obtaining hemolysis.

OBJECTIVES: Hemolysis is associated with erroneous or delayed results. Objectives of the study were to compare four different methods for obtaining hemolysis in vitro on three different analyzers. METHODS: Hemolysis was prepared with addition of pure hemoglobin into serum pool, osmotic shock, aspiration through blood collection needle, freezing/thawing of whole blood. Biochemistry parameters were measured in duplicate at Architect c8000 (Abbott, Abbott Park, USA), Beckman Coulter AU680 (Beckman Coulter, Brea, USA) and Cobas 6000 c501 (Roche, Mannheim, Germany), according to manufacturers' declarations. Cut-off value was defined as the highest value of H index with corresponding bias lower than acceptance criteria. RESULTS: We were not able to obtain results with freezing protocol. On all three platforms, lowest number of analytes were sensitive to hemolysis at H=0.5 using method of adding free hemoglobin. When osmotic shock was used, cut-off values for the most analytes were generally met at lower values. Hemolysis significantly interfered with measurement of potassium and lactate dehydrogenase (LD) at H=0.5 on all platforms. The most of the tested analytes had the lowest acceptable H index when aspiration method was used. At the low level of hemolysis (H=0.8) glucose, sodium, potassium, chloride, phosphate, and LD were affected on all analyzers, with some additional analytes depending on the manufacturer. CONCLUSIONS: Hemolysis interference differs on different analyzers and according to protocol for obtaining hemolysis. Aspiration method was generally the most sensitive to hemolysis interference, while addition of free Hb was the most resistant.

Circulating Tumor Cells in Colorectal Cancer: Detection Systems and Clinical Utility.

Colorectal cancer (CRC) is the third most common cancer worldwide. The high mortality from CRC is mainly related to metastasis affecting distant organs and their function. Dissemination of tumor cells from the primary tumor and hematogeneous spread are considered crucial in the formation of tumor metastases. The analysis of circulating tumor cells (CTCs) and CTC clusters in the blood can be used for the early detection of invasive cancer. Moreover, CTCs have a prognostic significance in the monitoring of a malignant disease or the response to chemotherapy. This work presents an overview of the research conducted on CTCs with the aim of finding suitable detection systems and assessing the possibility of clinical applications in patients with CRC.

Association of polymorphisms in promoter region of TNF-α -238 and -308 with clinical outcomes in patients with immune-mediated inflammatory diseases on anti-TNF therapy.

The hypothesis of the study was that polymorphisms in promoter regions -238 and -308 of TNF-α could be associated with different clinical outcomes in inflammatory bowel diseases (IBD) and immune-mediated rheumatic diseases (IMRD). The aim was to examine the possible association of both polymorphisms with concentration of C-reactive protein (CRP) and fecal calprotectin (fCAL), onset of the remission and development of the ADA in patients on therapy with anti-TNF inhibitors. The prospective study was done in patients with IBD and IMRD on infliximab (IFX) or adalimumab (ADM). Patients were genotyped for TNF-α -238 and -308 polymorphisms. The concentration of CRP, fCAL, IFX or ADM and antibodies to drugs were measured according to manufacturer's instructions and followed-up for 6 or 12 months. Out of all patients (N = 112), number of patients in remission did not differ according to genotypes (for IBD patients P = 0.509 vs 0.223; for IMRD patients P = 0.541 vs 0.132 for TNF-α -238 and -308, respectively). Initial CRP concentration was higher in IBD patients with TNF-α -308 GG than GA/AA genotypes in patients who failed to achieve remission [11.8 (4.4-39.6) vs 3.1 (1.5-6.5), P = 0.033]. In IBD patients with remission, fCAL concentration after at least 6 months of therapy was higher in TNF-α-308 GG than in GA genotype [52 (25-552) vs 20 (20-20) µg/g, P = 0.041]. Our results showed the association of TNF-α -308 GG genotype with a higher concentration of CRP and fecal calprotectin in patients with inflammatory bowel diseases on IFX or ADM therapy. Clinical remission and development of antibodies to anti-TNF drugs were not associated with TNF-α -238 and -308 polymorphisms.

Profiling Colorectal Cancer in the Landscape Personalized Testing-Advantages of Liquid Biopsy.

Drug-specific therapeutic approaches for colorectal cancer (CRC) have contributed to significant improvements in patient health. Nevertheless, there is still a great need to improve the personalization of treatments based on genetic and epigenetic tumor profiles to maximize the quality and efficacy while limiting cytotoxicity. Currently, CEA and CA 19-9 are the only validated blood biomarkers in clinical practice. For this reason, laboratories are trying to identify new specific prognostics and, more importantly, predictive biomarkers for CRC patient profiling. Thus, the unique landscape of personalized biomarker data should have a clinical impact on CRC treatment strategies and molecular genetic screening tests should become the standard method for diagnosing CRC. This review concentrates on recent molecular testing in CRC and discusses the potential modifications in CRC assay methodology with the upcoming clinical application of novel genomic approaches. While mechanisms for analyzing circulating tumor DNA have been proven too inaccurate, detecting and analyzing circulating tumor cells and protein analysis of exosomes represent more promising options. Blood liquid biopsy offers good prospects for the future if the results align with pathologists' tissue analyses. Overall, early detection, accurate diagnosis and treatment monitoring for CRC with specific markers and targeted molecular testing may benefit many patients.

Genetic and lifestyle predictors of ischemic stroke severity and outcome.

BACKGROUND: Different models that include clinical variables and blood markers have been investigated to predict acute ischemic stroke treatment course and recovery. AIM: The aim of the study was to investigate associations between lipid levels, lifestyle factors, hemostatic (F5, F2, SERPINE1, F13A1, and FGB), and atherogenic (APOA5 and ACE) gene variants and acute ischemic stroke (AIS) severity. MATERIALS AND METHODS: This study included 250 patients with AIS in which F5, F2, SERPINE1, F13A1, FGB, APOA5, and ACE genotypes were determined. Total cholesterol (TC), high-density cholesterol, low-density cholesterol, and triglycerides concentrations were measured within 24 h of the AIS onset. Examination of the neurological deficit was done using National Institutes of Health Stroke Scale/Score (NIHSS). RESULTS: APOA5 genotype [TC + CC] was more frequent (P = 0.026) in patients with the NIHSS score ≥ 21. Univariate regression analysis has shown that triglycerides (OR 0.55, 95% CI 0.34-0.91; P = 0.019), obesity (0.28, 95% CI 0.10-0.73; P = 0.010), age (OR 1.08, 95% CI 1.04-1.13; P < 0.001), and APOA5 genotype (TC + CC) (OR 2.40, 95% CI 1.10-5.25; P = 0.034) are significantly associated with a severe stroke. When all variables were included in model age (OR 1.06, 95% CI 1.01-1.11; P = 0.018), obesity (OR 0.25, 95% CI 0.08-0.77; P = 0.016) and APOA5 genotype (TC + CC) (OR 3.26, 95% CI 1.29-8.23; P = 0.012) remained significant for the risk of severe AIS. CONCLUSION: APOA5 genotype (TC + CC), age, and obesity could be used as prognostic risk factors for a very severe stroke (NIHSS ≥ 21).

Precision, accuracy, cross reactivity and comparability of serum indices measurement on Abbott Architect c8000, Beckman Coulter AU5800 and Roche Cobas 6000 c501 clinical chemistry analyzers.

BACKGROUND: The aim of our study was to perform verification of serum indices on three clinical chemistry platforms. METHODS: This study was done on three analyzers: Abbott Architect c8000, Beckman Coulter AU5800 (BC) and Roche Cobas 6000 c501. The following analytical specifications were verified: precision (two patient samples), accuracy (sample with the highest concentration of interferent was serially diluted and measured values compared to theoretical values), comparability (120 patients samples) and cross reactivity (samples with increasing concentrations of interferent were divided in two aliquots and remaining interferents were added in each aliquot. Measurements were done before and after adding interferents). RESULTS: Best results for precision were obtained for the H index (0.72%-2.08%). Accuracy for the H index was acceptable for Cobas and BC, while on Architect, deviations in the high concentration range were observed (y=0.02 [0.01-0.07]+1.07 [1.06-1.08]x). All three analyzers showed acceptable results in evaluating accuracy of L index and unacceptable results for I index. The H index was comparable between BC and both, Architect (Cohen's κ [95% CI]=0.795 [0.692-0.898]) and Roche (Cohen's κ [95% CI]=0.825 [0.729-0.922]), while Roche and Architect were not comparable. The I index was not comparable between all analyzer combinations, while the L index was only comparable between Abbott and BC. Cross reactivity analysis mostly showed that serum indices measurement is affected when a combination of interferences is present. CONCLUSIONS: There is heterogeneity between analyzers in the hemolysis, icteria, lipemia (HIL) quality performance. Verification of serum indices in routine work is necessary to establish analytical specifications.

Plasminogen activator inhibitor-1 activity and long-term outcome in patients with ST-elevation myocardial infarction treated with primary percutaneous coronary intervention: a prospective cohort study.

AIM: To determine the relationship between plasminogen activator inhibitor-1 (PAI-1) activity rise during the first 24 hours of ST-elevation myocardial infarction (STEMI) treatment and death after 5 years. METHODS: From May 1, 2009 to March 23, 2010, 87 STEMI patients treated with primary percutaneous coronary intervention (PCI) at the Sestre Milosrdnice University Hospital Center were consecutively enrolled in prospective single-center cohort study. PAI-1 activity was determined on admission and 24 hours later. The primary end-point was death after 5 years. The predictive value of PAI-1 activity variables as biomarkers of death was assessed using receiver operating characteristic (ROC) curve, independent predictors of death were assessed using multivariate Cox regression, and covariates independently related to higher PAI-1 activity rise were assessed using linear regression. RESULTS: Two patients died during the hospital treatment and 11 during the follow-up. PAI-1 activity rise had the largest area under curve (0.748) for predicting death rate (optimal cut-off point 3.7 U/mL, sensitivity 53.8%, specificity 90.5%). Patients with PAI-1 activity rise higher than 3.7 U/mL had significantly higher mortality (P<0.001). Kaplan-Meier survival curve diverged within the first year after STEMI. Independent predictors of death were PAI-1 rise and final Thrombolysis in Myocardial Infarction flow. PAI-1 activity rise was independently related to heart failure, thrombus aspiration, and body weight. CONCLUSION: PAI-1 activity rise higher than 3.7 U/mL is associated with higher 5-year death rate in STEMI patients treated with primary PCI.

Croatian laboratories have a good knowledge of the proper detection and management of hemolyzed, icteric and lipemic samples.

BACKGROUND: Endogenous interferences are an important source of biased laboratory results. Hemolysis, lipemia and icteria are the main source of endogenous interference in laboratory medicine. Accreditation according to ISO 15189 improves the overall quality of the laboratory procedures. The aim of our study was i) to assess the level of knowledge of Croatian medical biochemists about the proper detection and management of hemolysis, lipemia and icteria; and ii) to identify possible differences in the level of knowledge respective to the laboratory accreditation status. METHODS: An on-line self-report survey was carried out by the Working Group for Preanalytical Phase of the Croatian Society of Medical Biochemistry and Laboratory Medicine during April to May 2015. Survey included 14 statements (Q1-Q14) about procedures for samples with interferences and participants were asked to assess the degree of agreement with the statement using a 4-point Likert scale. RESULTS: The lowest level of knowledge was observed for statements Q10 (dealing with icteric sample; 40.9% participants agreed with the correct procedure), Q12 (allowable error for interference; 47.2%) and Q11 (dealing with lipemic sample; 60.1%). Almost all participants (97.4%) agreed that laboratories in Croatia should have a harmonized protocol for management of samples with interferences. Participants from accredited laboratories showed higher knowledge of hemolysis detection (p=0.031), rejection of hemolyzed sample (p<0.001), management of icteric samples (p=0.038) and allowable error for interferences (p=0.040). CONCLUSIONS: Croatian laboratories have a good knowledge of the proper detection and management of hemolyzed, icteric and lipemic samples. Accreditation is associated with higher knowledge about management of samples with interferences.

Genome-wide association study identifies genetic risk underlying primary rhegmatogenous retinal detachment.

Rhegmatogenous retinal detachment (RRD) is an important cause of vision loss and can potentially lead to blindness. The underlying pathogenesis is complex and incompletely understood. We applied a two-stage genetic association discovery phase followed by a replication phase in a combined total of 2833 RRD cases and 7871 controls. The discovery phase involved a genome-wide association scan of 867 affected individuals and 1953 controls from Scotland, followed by genotyping and testing 4347 highest ranking or candidate single nucleotide polymorphisms (SNPs) in independent sets of cases (1000) and controls (2912) of Dutch and British origin. None of the SNPs selected reached a Bonferroni-corrected threshold for significance (P < 1.27 × 10(-7)). The strongest association, for rs12960119 (P = 1.58 × 10(-7)) located within an intron of the SS18 gene. Further testing was carried out in independent case-control series from London (846 cases) and Croatia (120 cases). The combined meta-analysis identified one association reaching genome-wide significance for rs267738 (OR = 1.29, P = 2.11 × 10(-8)), a missense coding SNP and eQTL for CERS2 encoding the protein ceramide synthase 2. Several of the top signals showing suggestive significance in the combined meta-analysis encompassed genes with a documented role in cell adhesion or migration, including SS18, TIAM1, TSTA3 and LDB2, which warrant further investigation. This first genetic association study of RRD supports a polygenic component underlying RRD risk since 27.4% of the underlying RRD liability could be explained by the collective additive effects of the genotyped SNP from the discovery genome-wide scan.

Serotonin transporter polymorphism (5-HTTLPR) in Croatian population.

Serotonin transporter polymorphism (5-HTTLPR) is a well-studied polymorphism in psychiatric research. The function of serotonin transporter is to control neural stimulation and maintain homeostasis of serotonin in other cells like platelets and enterochromaffin cells. Considering serotonin function in human behavior, and the role of serotonin transporter, 5-HTTLPR has been associated with depression related disorders, anxiety related personality traits, and adverse response to psychotherapy. However, many studies failed to replicate the association of 5-HTTLPR polymorphism with mentioned disorders. The aim of our study was to assess genotype frequencies in Croatian physically and psychologically healthy population and compare our results with previously published data. Genotype distribution in our research was similar to previous studies on Caucasian population regardless of inclusion criteria. Genotype distribution was as follows: LL 38 %; LS 45 %; SS 17 % and allele frequencies for L and S allele were 61 and 39 %, respectively. Obtained results were in an agreement with the Hardy-Weinberg equilibrium. Comparing inclusion criteria from different studies, we noticed a difference in population selection from one study to another. Increased possibility for selection bias, population stratification and complexity of psychiatric disorders might present a source of possible errors in genetic association studies.

Paraoxonase and arylesterase activity of paraoxonase 1 and oxidative stress parameters in cervical intraepithelial neoplasia.

Introduction: Paraoxonase 1 (PON1) is the enzyme that removes carcinogenic radicals from lipids. The aim of the study was to investigate the differences in PON1 activity and oxidation stress parameters between patients with cervical intraepithelial neoplasia (CIN) and healthy controls. Materials and methods: The study included 65 women with CIN and 109 healthy women. Lipid parameters were determined on Cobas Integra 400 plus (Roche, Mannheim, Germany). Tiols and reduced glutathione (GSH) were determined spectrophotometric using Eliman reagent. Activity of PON1 was assessed with two substrates, paraoxon and phenylacetate by spectrophotometric method. Malondialdehyde (MDA) was determined by high performance liquid chromatography (Shimadzu Corporation, Kyoto, Japan). Mann-Whitney-test, t-test, χ2-test, correlation and logistic regression was used in statistical analysis. P < 0.05 was considered statistically significant. Results: The basal (P = 0.929) and NaCl-stimulated (P = 0.985) PON1 activity and activities standardised on the concentration of high-density lipoprotein (HDL; P = 0.076; P = 0.065, respectively) and apolipoprotein AI (apo AI; P = 0.444; P = 0.499, respectively) as well as PON1 phenotypes (P = 0.842) did not differ significantly between the groups. The PON1 arylesterase activity (53±19 kU/L vs. 77±17 kU/L; P < 0.001) and HDL-standardized activity (37 (28-44) kU/mmol vs. 43 (37-50) kU/mmol; P < 0.001) and apoAI (29±11 kU/g vs. 44±11 kU/g; P < 0.001) was significantly reduced in the CIN group. The concentration of the thiol groups was similar (P = 0.519), of MDA was lower (0.39 (0.27-0.55) µmol/L vs. 0.76 (0.57-1.15) µmol/L; P < 0.001) and of GSH was higher (112.0 (66.0-129.6) µg/mL vs. 53.4 (34.8-134.4) µg/mL; P < 0.001) in the CIN group. Conclusion: Reduced PON1 arylesterase activity, lower MDA and higher GSH concentration were observed in CIN patients.

Algorithm for Rapid Exclusion of Clinically Relevant Plasma Levels of Direct Oral Anticoagulants in Patients Using the DOAC Dipstick: An Expert Consensus Paper.

BACKGROUND: With the widespread use of direct oral anticoagulants (DOACs), there is an urgent need for a rapid assay to exclude clinically relevant plasma levels. Accurate and rapid determination of DOAC levels would guide medical decision-making to (1) determine the potential contribution of the DOAC to spontaneous or trauma-induced hemorrhage; (2) identify appropriate candidates for reversal, or (3) optimize the timing of urgent surgery or intervention. METHODS AND RESULTS: The DOAC Dipstick test uses a disposable strip to identify factor Xa- or thrombin inhibitors in a urine sample. Based on the results of a systematic literature search followed by an analysis of a simple pooling of five retrieved clinical studies, the test strip has a high sensitivity and an acceptably high negative predictive value when compared with levels measured with liquid chromatography tandem mass spectrometry or calibrated chromogenic assays to reliably exclude plasma DOAC concentrations ≥30 ng/mL. CONCLUSION: Based on these data, a simple algorithm is proposed to enhance medical decision-making in acute care indications useful primarily in hospitals not having readily available quantitative tests and 24/7. This algorithm not only determines DOAC exposure but also differentiates between factor Xa and thrombin inhibitors to better guide clinical management.

Angiotensin-converting enzyme insertion/deletion polymorphism genotyping error: the cause and a possible solution to the problem.

Rigat and colleagues were the first ones to develop a rapid PCR-based assay for identifying the angiotensin converting enzyme insertion/deletion (I/D) polymorphism. Due to a big difference between the length of the wild-type and mute alleles the PCR method is prone to mistyping because of preferential amplification of the D allele causing depicting I/D heterozygotes as D/D homozygotes. The aim of this study was to investigate whether this preferential amplification can be repressed by amplifying a longer DNA fragment in a so called Long PCR protocol. We also aimed to compare the results of genotyping using five different PCR protocols and to estimate the mistyping rate. The study included 200 samples which were genotyped using standard method used in our laboratory, a stepdown PCR, PCR protocol with the inclusion of 4 % DMSO, PCR with the use of insertion specific primers and new Long PCR method. The results of this study have shown that accurate ACE I/D polymorphism genotyping can be accomplished with the standard and the Long PCR method. Also, as of our results, accurate ACE I/D polymorphism genotyping can be accomplished regardless of the method used. Therefore, if the standard method is optimized more cautiously, accurate results can be obtained by this simple, inexpensive and rapid PCR protocol.

Visfatin is not associated with inflammatory markers in patients on hemodialysis.

BACKGROUND: Cardiovascular events are a major cause of death in patients with end-stage renal disease. Endothelial dysfunction represents a key event in atherosclerosis development and has been implicated in the pathophysiology of different forms of cardiovascular disease, including chronic kidney disease. In recent years, visfatin, a ubiquitous adipokine, has been described as a potent marker of endothelial inflammation and dysfunction. The aim of the study was to investigate the association of visfatin with well-known markers of inflammation and endothelial dysfunction. METHODS: Serum and plasma samples from 66 patients (40 males and 26 females) treated by hemodialysis were analysed for visfatin, fibrinogen, CRP, PAI-1 levels. Visfatin was determined by ELISA method while CRP, fibrinogen and PAL-1 were obtained by standard laboratory methods. RESULTS: We observed statistically significant correlation between visfatin level and fibrinogen (r = 0.51; p = 0.008) and the time on dialysis in female patients (r = 0.70; p < 0.001). PAI-1 and CRP did not correlate with visfatin in males nor in females. CONCLUSIONS: Visfatin is correlated with time on dialysis and with fibrinogen only in female dialysis patients. To confirm this, further studies are needed with a higher number of patients.

Impact of SGLT2 inhibitors on the mechanisms of myocardial dysfunction in type 2 diabetes: A prospective non-randomized observational study in patients with type 2 diabetes mellitus without overt heart disease.

AIMS: This prospective observational study evaluated the possible mechanisms of action of SGLT2 inhibitors (SGLT2i) in patients with type 2 diabetes mellitus (T2DM) without overt heart disease. METHODS: The study was designed to verify whether SGLT2i impact biomarkers of: myocardial stress-NT-proBNP, inflammation-high sensitivity C-reactive protein, oxidative stress -myeloperoxidase, functional and structural echocardiographic parameters, in patients with T2DM on metformin (heart failure stages A and B) who needed treatment intensification with a second antidiabetic agent. The patients were divided in two groups - the ones planned to receive SGLT2i or DPP-4 inhibitor (except saxagliptin). At baseline, and after six months of therapy, 64 patients underwent blood analysis, physical and echocardiography examination. RESULTS: There were no significant differences between the two groups in terms of biomarkers of myocyte and oxidative stress, inflammation and blood pressure. Body mass index, triglycerides, aspartate aminotransferase, uric acid, E/E', deceleration time and systolic pressure in the pulmonary artery significantly decreased, while stroke volume, indexed stroke volume, high-density lipoprotein, hematocrit and hemoglobin significantly increased in the group on SGLT2i. CONCLUSIONS: According to the results, SGLT2i mechanisms of action comprise rapid changes in body composition and metabolic parameters, reduced cardiac load and improvement in diastolic and systolic parameters.

Corrigendum to: Post-treatment neutrophil to lymphocyte ratio as a prognostic tool in patients treated with tocilizumab for severe COVID-19 pneumonia - a single center experience.

[This corrects the article DOI: 10.11613/BM.2023.020704.].

Direct oral anticoagulants (DOACs): From the laboratory point of view.

Direct oral anticoagulants (DOACs) represent a new generation of drugs that have been increasingly used in the prevention and treatment of thromboembolic states. According to the mechanism of anticoagulant action, DOACs are divided into two groups: direct inhibitors of thrombin (dabigatran) and direct inhibitors of activated factor X (FXa) (rivaroxaban, apixaban, edoxaban, betrixaban). Compared to the vitamin K antagonists, DOACs are superior in terms of onset of action, pharmacokinetic and pharmacodynamics properties and fixed daily dose without the need for routine coagulation monitoring. Despite these advantages, there are clinical conditions in which laboratory measurement of DOACs should be performed. Although DOACs have an impact on screening haemostasis assays (prothrombin time, PT; activated partial thromboplastin time, aPTT; and thrombin time, TT), these tests are not appropriate for quantifying drug levels. Therefore, specific quantitative methods (LC-MS/MS as a gold standard method for all DOACs, coagulometric and chromogenic assays for dabigatran, and chromogenic anti-Xa assays with drug-specific calibrators for inhibitors of FXa) should only be used for determination of DOACs concentration. The aim of this review is to present all aspects of laboratory assessment of DOACs, including pre-analytical, analytical and post-analytical factors in the overall testing process with a special accent on the available specific quantitative methods for measurement of DOACs in circulation.

Verification policies in Croatian medical biochemistry laboratories: a survey of the practice.

Introduction: The aim of this study was to screen practices used in verification procedures for methods/analysers among medical biochemistry laboratories (MBLs) in Croatia. We hypothesized that these procedures differ widely from laboratory to laboratory and wanted to gather specific data on steps used in the verification workflow. Materials and methods: In order to obtain data, an online survey was conducted. The survey, divided in two sections, contained 29 questions and statements addressing general characteristics and specific steps of the verification workflow of each individual MBL. The survey was disseminated among managers of all MBLs in Croatia. Results: A total of 108/196 (55%) laboratories participated in the survey. Forty nine MBLs were excluded from the second part of the survey: 14 have not implemented verification procedures, and 35 MBLs due to the absence of answers. The most relevant results of the second part of the survey showed that: 18/59 (0.31) of the responding MBLs have difficulties when defining acceptance criteria, 27/59 (0.46) used the Clinical and Laboratory Standards Institute protocol for precision estimation; the majority of MBLs used a median of 20 samples for method/analyser comparisons and estimated bias using internal quality control samples; reference intervals provided by external sources are mainly adopted; 60% of MBLs do not include linearity verification in their protocol and do not use the national document for the estimation of measurement uncertainty. Conclusions: Heterogeneous verification protocols are routinely utilized across Croatian MBLs which clearly confirms that a national document might help in the harmonization of verification procedures.

DOAC Dipstick Testing Can Reliably Exclude the Presence of Clinically Relevant DOAC Concentrations in Circulation.

In certain clinical situations, it is necessary to determine whether clinically relevant plasma levels of direct oral anticoagulants (DOACs) are present. We examined whether qualitative testing of DOACs in urine samples can exclude DOAC plasma concentrations of ≥30 ng/mL. This prospective single-center cohort study included consecutive patients treated with an oral direct factor Xa inhibitor (DXI) (apixaban, n = 31, rivaroxaban, n = 53) and direct thrombin inhibitor (DTI) (dabigatran, n = 44). We aimed to define the negative predictive value (NPV) and other statistical parameters of detecting DXIs and DTIs by DOAC Dipstick at plasma concentrations of ≥30 ng/mL. We also determined the best-fit threshold plasma levels using chromogenic substrate assays by logistic regression analysis. Between July 2020 and July 2021, 128 eligible patients (mean age 66 years, 55 females) were included into the study. The NPVs and sensitivities for DXI and DTI of DOAC Dipstick were 100% at ≥30 ng/mL plasma, for specificities 6 and 21% and for positive predictive values 62 and 72%, respectively. All diagnostic statistical tests improved to values between 86 and 100% at best-fitting plasma thresholds of ≥14 ng/mL for DXI and ≥19 ng/mL for DTI. Visual analysis using the DOAC Dipstick was 100% in agreement with that of the optoelectronic DOASENSE Reader for all the three DOACs.DOAC Dipstick testing can reliably exclude the presence of DOACs in urine samples at best-fitting thresholds of >14 and >19 ng/mL in plasma. The performance of the DOAC Dipstick at detecting lower DOAC concentrations in plasma requires confirmation.