Pre-analytical practices for routine coagulation tests in European laboratories. A collaborative study from the European Organisation for External Quality Assurance Providers in Laboratory Medicine (EQALM).

Background Correct handling and storage of blood samples for coagulation tests are important to assure correct diagnosis and monitoring. The aim of this study was to assess the pre-analytical practices for routine coagulation testing in European laboratories. Methods In 2013-2014, European laboratories were invited to fill in a questionnaire addressing pre-analytical requirements regarding tube fill volume, citrate concentration, sample stability, centrifugation and storage conditions for routine coagulation testing (activated partial thromboplastin time [APTT], prothrombin time in seconds [PT-sec] and as international normalised ratio [PT-INR] and fibrinogen). Results A total of 662 laboratories from 28 different countries responded. The recommended 3.2% (105-109 mmol/L) citrate tubes are used by 74% of the laboratories. Tube fill volumes ≥90% were required by 73%-76% of the laboratories, depending upon the coagulation test and tube size. The variation in centrifugation force and duration was large (median 2500 g [10- and 90-percentiles 1500 and 4000] and 10 min [5 and 15], respectively). Large variations were also seen in the accepted storage time for different tests and sample materials, for example, for citrated blood at room temperature the accepted storage time ranged from 0.5-72 h and 0.5-189 h for PT-INR and fibrinogen, respectively. If the storage time or the tube fill requirements are not fulfilled, 72% and 84% of the respondents, respectively, would reject the samples. Conclusions There was a large variation in pre-analytical practices for routine coagulation testing in European laboratories, especially for centrifugation conditions and storage time requirements.

Salt Disproportionation in the Solid State: Role of Solubility and Counterion Volatility.

Disproportionation propensity of salts (HCl, HBr, heminapadisylate) and adipic acid cocrystal of corticotropin releasing hormone receptor-1 antagonist was studied using model free kinetics. Using thermogravimetic weight loss profile or heat flow curves from differential scanning calorimetry, an activation energy plot for salts and cocrystal was generated based on model free kinetics. This activation energy of disproportionation provided qualitative information about the solid state salt stability. To ensure the stability throughout the shelf life, "prototype" formulations of salts and cocrystal in tablet form were stored at 40 °C and several water vapor pressures. Disproportionation kinetics were studied in these prototype tablet formulations using two-dimensional X-ray diffractometry. Formulations containing the adipic acid cocrystal or heminapadisylate salt did not show disproportionation of API when stored at 40 °C/75% RH for 300 days. On the other hand, formulations containing HCl or HBr salt disproportionated. Though isostructural, the disproportionation propensity of HBr and HCl salts was quite different. The HCl salt highlighted the important role that volatility of the counterion plays in the physical stability of the formulations. Solution state stability (i.e., in dissolution medium) of salts and cocrystal was also assessed and compared with solid state stability, by determining their solubility at different pH's, and intrinsic dissolution rate.

Bridging the gap between point-of-care testing and laboratory testing in hemostasis.

Point-of-care (POC) testing within hemostasis is an expanding field, with the most widely used test being POC international normalized ratio (INR). Many of these devices are being used in a nonlaboratory setting by staff with no laboratory training. In the United Kingdom, external quality assessment (EQA) is provided by the organization UK National External Quality Assessment Scheme for Blood Coagulation (UK NEQAS BC). Participants within the UK NEQAS BC POC INR program are largely based in primary care (77%), with the majority of EQA samples and patients tests being performed by nurses (70%). Many of these centers do not have support from the laboratory staff and may, therefore, not understand the requirement for a robust quality control (QC) system comprising both internal quality control (IQC) and EQA. From data acquired through a questionnaire of these UK NEQAS BC users, we observed that 2% of the centers never perform IQC tests, only 29% perform IQC tests when starting a new batch of test strips, and just 15% carry out IQC with each clinic as recommended by the UK guidelines. The imprecision of EQA tests was greater for POC users than in the UK NEQAS BC hospital laboratory program, with average coefficients of variation for a 2-year period of 11.0 and 7.3%, respectively. This may reflect the handling of EQA samples rather than the imprecision of the method, due to the lack of laboratory training amongst POC staff. POC INR in the UK could greatly benefit from more interaction and support from laboratories to these POC testers.

Examining Food Security, Choices and Barriers among Community Supported Agriculture participants during COVID- 19 in Kentucky.

The coronavirus disease (COVID-19) pandemic is challenging food security. Our study's purpose was to examine relationships among food security status, eating patterns and perceived barriers to food choices among shareholders (N= 209) in a Community Supported Agriculture (CSA) program during stay-at-home restrictions due to the pandemic. The food insecure group (n= 33) reported lower consumption of fruits/vegetables, whole grains and greater consumption of fast foods and more barriers to food choices compared to the food secure group (p<.05). A low food insecure proportion (16%) among the CSA participants suggests a potential role of a CSA program to prevent food insecurity.

Clotting and chromogenic factor VIII assay variability in post-infusion and spiked samples containing full-length recombinant FVIII or recombinant factor VIII Fc fusion protein (rFVIIIFc).

INTRODUCTION: Variability in FVIII measurement is a recognized problem. There are limited data for samples containing recombinant Factor VIII Fc fusion protein (rFVIIIFc). Many studies use samples for which factor concentrate has been spiked into FVIII deficient plasma in vitro. This approach requires validation. AIM/METHODS: Four samples were distributed in a UK National External Quality Assessment Scheme for Blood Coagulation (NEQAS BC) survey. One contained Advate (full-length recombinant FVIII) (rFVIII) added to FVIII deficient plasma, one was from a severe haemophilia A patient after infusion of Advate, one was prepared by addition of rFVIIIFc (marketed as Elocta/Eloctate) to FVIII deficient plasma and the fourth was collected from a severe haemophilia A patient following rFVIIIFc (Eloctate) infusion. Fifty-three haemophilia centres (UK and Scandinavia) performed one-stage FVIII assays and 27 performed chromogenic FVIII assays. RESULTS/CONCLUSIONS: One-stage assays gave significantly lower results than chromogenic assays by 7% (P < 0.01) and 13%(P < 0.001) for post-Advate and Advate spiked samples, and by 22% (P < 0.001) and 23% (P < 0.001) for post-rFVIIIFc and rFVIIIFc spiked samples. The interlaboratory variation was similar for all samples, with CVs of 12%-16% (chromogenic) and 10%-13% (one stage). The data indicate that either product can be safely monitored by one-stage or chromogenic assay. Spiked samples behaved in a similar way to post-infusion samples for both products and could be substituted for post-infusion samples for use in proficiency testing exercises (ie, samples were commutable).

Laboratory D-dimer measurement: improved agreement between methods through calibration.

Accurate and precise measurement of plasma D-dimer levels is important in the diagnosis and management of venous thromboembolism. Considerable variability in D-dimer results obtained using different methods has, however, been reported in multicentre studies. This study explored in two separate multicentre exercises the degree of precision amongst laboratory D-dimer measurements, and the degree by which inter-method agreement could be improved using a calibration curve model. The first exercise demonstrated generally good within-centre precision, with 82% of the centres reporting results for two identical but differently coded samples within 10% of each other. However, six centres reported results which would have excluded deep vein thrombosis (DVT) for one sample but failed to exclude DVT for the other, identical sample. In the second exercise, overall between-method precision of D-dimer results for two samples was shown to improve markedly when a calibration model was applied, using the consensus median values obtained by all participants for three "calibration plasmas" to recalculate D-dimer values. For centres reporting results in fibrinogen equivalent units (FEUs), between-centre coefficients of variation (CVs) fell from 25.9% to 11.6% and 22.4% to 7.7%, respectively, for the two samples. For centres reporting in ng/ml, CVs fell from 45.3-21.6% and 40.8-11.6%, respectively. In conclusion, improved harmonisation of D-dimer results by different methods may be achieved by a calibration model and common calibrant plasmas.

Discovery and Characterization of 2-Acylaminoimidazole Microsomal Prostaglandin E Synthase-1 Inhibitors.

As part of a program aimed at the discovery of antinociceptive therapy for inflammatory conditions, a screening hit was found to inhibit microsomal prostaglandin E synthase-1 (mPGES-1) with an IC50 of 17.4 µM. Structural information was used to improve enzyme potency by over 1000-fold. Addition of an appropriate substituent alleviated time-dependent cytochrome P450 3A4 (CYP3A4) inhibition. Further structure-activity relationship (SAR) studies led to 8, which had desirable potency (IC50 = 12 nM in an ex vivo human whole blood (HWB) assay) and absorption, distribution, metabolism, and excretion (ADME) properties. Studies on the formulation of 8 identified 8·H3PO4 as suitable for clinical development. Omission of a lipophilic portion of the compound led to 26, a readily orally bioavailable inhibitor with potency in HWB comparable to celecoxib. Furthermore, 26 was selective for mPGES-1 inhibition versus other mechanisms in the prostanoid pathway. These factors led to the selection of 26 as a second clinical candidate.

Point of Care INR testing devices: performance of the Roche CoaguChek XS and XS Plus in the UK NEQAS BC external quality assessment programme for healthcare professionals: four years' experience.

BACKGROUND: Vitamin K antagonists have been used for many decades and have been traditionally monitored by the measurement of the International Normalised Ratio (INR) in the laboratory. Introduction of Point of Care (POC) testing devices to measure INR has resulted in many tests being undertaken in primary care. External Quality Assessment (EQA) of these POC devices is recommended to ensure accuracy and reliability of INR results outside a laboratory setting. AIM: To assess the quality of INR results for users of two POC devices (CoaguChek XS and CoaguChek XS Plus) over a four-year period. METHODS: Four surveys (two samples) were sent in each 12-month period. The median INR value of each sample was calculated and the percentage deviation from this median determined. Any results greater than 15% from the median were considered to be outside consensus which indicated a possible problem within the testing system. RESULTS: Variability of INR results in this UK National External Quality Assessment Scheme (NEQAS) programme was comparable to that in the UK NEQAS EQA programme for laboratory INR testing. Occurrence of persistent problems was lower in the POC programme than the laboratory programme. CONCLUSIONS: Utilisation of an EQA programme for POC devices in primary care is feasible and necessary. Our data suggest for those health professionals using EQA, the reliability and accuracy of INR testing matches the quality of laboratory testing.

Physical stability of salts of weak bases in the solid-state.

When selecting the physical form of an active pharmaceutical substance, there is often a question of when a molecule's pKa renders it too low for salt formation and formulation into a product that will be sufficiently physically stable to provide adequate shelf life. In the paper, a graph is provided that tabulates pKa values of active pharmaceuticals versus the salt or free base form that was chosen to be developed as an orally administered drug product. Tabulation of the data provides insight into where, if any, practical cutoff exists, under which salt formation should not be considered. Specific examples of disproportionation reactions are reviewed and are described in light of the concepts of pH maximum, pH microenvironment, and Gibbs free energy to gain further insight into when such reactions become favorable. The driving force for disproportionation reactions is substantially greater than that for polymorphic form conversion, and as a consequence, its probability of occurring in the solid-state is much greater when formulated in favorable microenvironments. Factors that influence the reaction rate are examined. It is concluded that each salt should be evaluated on the merit of its physical properties and often the most soluble salt will not be one's best choice. Unfortunately, compounds that stand to benefit the most from salt formation due to their exceptionally low intrinsic solubility are the ones that will be most likely to disproportionate if their pKa is relatively low.

Emerging technologies and quality assurance: the United Kingdom National External Quality Assessment Scheme perspective.

The pattern of tests employed and technologies developed within hemostasis laboratories has changed considerably within the last 10 years. These changes have presented challenges to external quality assessment (EQA) providers, including the United Kingdom National External Quality Assessment Scheme (NEQAS). EQA for point-of-care devices used for monitoring oral anticoagulant therapy has focused on provision of suitable material to assess performance of devices designed for capillary blood testing, and on education of a user group not usually trained in laboratory quality control procedures. Development of novel therapeutic agents for hemophilia has presented challenges regarding standardization of assays for monitoring treatment, whereas advances related to laboratory testing and automation have not always been accompanied by improved accuracy and precision. EQA provision has also been shown to be of value in molecular genetic screening tests for thrombophilia, and in highlighting standardization issues related to D-dimer measurement in the exclusion of deep vein thrombosis. The increasing prevalence of screening tests of global hemostasis, such as thrombin generation tests and thromboelastography, presents additional challenges to EQA providers in the attempt to standardize these new and potentially beneficial technologies.

Multilaboratory testing in thrombophilia through the United Kingdom National External Quality Assessment Scheme (Blood Coagulation) Quality Assurance Program.

We describe here results from the United Kingdom National External Quality Assessment Scheme (UK NEQAS) Thrombophilia Screening Program, in which an average of 21% of 280 centers reported an incorrect diagnosis for a series of plasma samples. Three case studies are described, showing causes of error in individual laboratories, related to the source of reference plasma or reagents. Methodological bias is also described. For protein C (PC) assays 18% of centers reported PC deficiency in a patient homozygous for factor V Leiden. Studies in the NEQAS laboratory confirmed the effect of activated protein C resistance (APCR) on clot-based PC activity assays. Differences in results obtained for PS-deficient subjects with different protein S (PS) activity kits are reported; several subjects would be misdiagnosed as normal with one kit if the manufacturer's reported reference range was adopted instead of a locally determined reference range. Antithrombin (AT) assays were shown to vary in their sensitivity to different molecular defects in the antithrombin gene; 77% of centers employing human thrombin-based activity assays reported a normal AT level in a patient with antithrombin Cambridge II. Sensitivity of the APC resistance test in the absence of factor V-deficient plasma was shown to be improved through normalization of results, and errors in the genetic diagnosis of factor V Leiden and the P20210A prothrombin gene mutation are described. Errors in the diagnosis of thrombophilic defects can therefore be identified through participation in EQA programs, and following dissemination of information, improvements in diagnosis can be demonstrated.

Lupus anticoagulant testing: improvements in performance in a UK NEQAS proficiency testing exercise after dissemination of national guidelines on laboratory methods.

Laboratory screening for lupus anticoagulant (LA) has been shown to be suboptimal in several studies. Guidelines have recently been published by an expert group for the British Committee for Standards in Haematology, in an attempt to standardize and improve screening procedures. The value of using screening tests conforming with these guidelines was investigated in a United Kingdom National External Quality Assessment Scheme (UK NEQAS) proficiency testing exercise. The correct diagnosis was achieved by 97% of laboratories for a LA-negative sample. However, 18.3% of centres reported a false-negative result for a sample from a LA-positive subject. A significantly higher proportion of centres that used methods conforming with the published guidelines achieved the correct diagnosis for this sample (P < 0.002, chi-square test). A wide variety of screening tests were used by laboratories in this study. Within-method agreement could be improved by the use of a common normal pooled plasma to determine ratios. However, between-method agreement was not improved by this procedure. We conclude that adoption of methods compliant with national guidelines may improve the diagnosis of LA. There is a need, however, for reference and standardization materials to ensure further improvement in the accuracy of LA methods.