Contamination of lithium heparin blood by K2-ethylenediaminetetraacetic acid (EDTA): an experimental evaluation

Introduction:

The contamination of serum or lithium heparin blood with ethylenediaminetetraacetic acid (EDTA) salts may affect accuracy of some critical analytes and jeopardize patient safety. The aim of this study was to evaluate the effect of lithium heparin sample contamination with different amounts of K₂EDTA.

Materials and methods:

Fifteen volunteers were enrolled among the laboratory staff. Two lithium heparin tubes and one K₂EDTA tube were collected from each subject. The lithium-heparin tubes of each subject were pooled and divided in 5 aliquots. The whole blood of K₂EDTA tube was then added in scalar amount to autologous heparinised aliquots, to obtained different degrees of K₂EDTA blood volume contamination (0%; 5%; 13%; 29%; 43%). The following clinical chemistry parameters were then measured in centrifuged aliquots: alanine aminotranspherase (ALT), bilirubin (total), calcium, chloride, creatinine, iron, lactate dehydrogenase (LD), lipase, magnesium, phosphate, potassium, sodium.

Results:

A significant variation starting from 5% K₂EDTA contamination was observed for calcium, chloride, iron, LD, magnesium (all decreased) and potassium (increased). The variation of phosphate and sodium (both increased) was significant after 13% and 29% K₂EDTA contamination, respectively. The values of ALT, bilirubin, creatinine and lipase remained unchanged up to 43% K₂EDTA contamination. When variations were compared with desirable quality specifications, the bias was significant for calcium, chloride, LD, magnesium and potassium (from 5% K₂EDTA contamination), sodium, phosphate and iron (from 29% K₂EDTA contamination).

Conclusions:

The concentration of calcium, magnesium, potassium, chloride and LD appears to be dramatically biased by even modest K₂EDTA contamination (i.e., 5%). The values of iron, phosphate, and sodium are still reliable up to 29% K₂EDTA contamination, whereas ALT, bilirubin, creatinine and lipase appear overall less vulnerable towards K₂EDTA contamination.     

Avoidance to wipe alcohol before venipuncture is not a source of spurious hemolysis

Background

It is still uncertain whether or not avoidance to let disinfectant alcohol dry at the site of venipuncture is a source of spurious hemolysis when drawing venous blood.

Methods:

In a consecutive series of 52 outpatients referred for routine laboratory testing, venous blood was drawn by direct venipuncture with (odd group) or without (pair group) wiping 70% isopropyl alcohol at the site of venipuncture. A 3.5 mL evacuated tube with clot activator and gel separator was drawn from a vein of the upper limb, serum was immediately separated with standard centrifugation and tested for potassium, lactate dehydrogenase (LD), aspartate aminotransferase (AST) and hemolysis index (HI) on Roche Cobas.

Results:

No specimen was discarded for unsatisfactory venipuncture. No differences for age and gender were observed between groups. As regards the four parameters investigated, no significant differences could be observed between patients in whom blood was drawn with or without letting the alcohol dry. It is also noteworthy that no sample in both groups exceeded the conventional sample rejection threshold of cell-free hemoglobin.

Conclusions:

The results of our prospective, randomized study attest that failure to wipe alcohol at the site of venipuncture should not be considered as a potential source of spurious hemolysis when drawing blood.     

Another development training programme? Education for practical engagement in extension and development work

Current development education in the United Kingdom usually offers participants from developing countries studies of what development is or should be. These programmes are well suited to the needs of higher-level planners or policy researchers. They contrast markedly with the urgent need for the knowledge of and skills in how to undertake planned economic and social changes. This paper suggests a possible route towards a practical, professional training for middle-and lower-level personnel engaged in managing development and extension services. Briefly, the paper notes the lack of educational programmes aimed at practical training and middle-level staff in Britain; and the role of education in the process of development. Current difficulties for locating these programmes in the developing countries themselves are discussed, and the outline for a suitably practical programme, initially based in Britain, is proposed.     

Applying the technology acceptance model to a Spanish City Hall

This paper examines the relative importance and significance of the four technology enablers introduced by Davis (1989) in the technology acceptance model (TAM) (perceived ease of use, perceived usefulness, attitude towards using and behavioural intention) for use on four different levels of citizen engagement in e-government (null, publish, interact and transact). An extended technology acceptance model (TAM) is developed to test citizen engagement towards online e-government services from a sample of 307 citizens who used the benefits advisor tool within a Spanish City Hall. Although the proposed model follows TAM and explains the intention towards the actual use of e-government by postulating four direct determinants, “A, PU, PEOU and BI” have been considered as parallel processes, meaning that each can have separate influence in different levels of citizen engagement. To achieve this goal, a multinomial logistic regression is developed and tested to confirm the explanatory power of the four technology enablers on the four different levels of e-government. Our findings further suggest that in order to implement e-government, some of the enablers matter more than others to move from one level of citizen engagement to another. The main contribution of the paper is to question the use of existing models which seek to represent the relationship between technology enablers and the adoption of e-government services without considering their impacts on citizens’ engagement. The implications of the findings are discussed and useful insights are provided in relation to policy recommendations geared to create appropriate conditions to build citizens’ engagement intent of use of e-government services.     

IS THERE A TWO-STEP FLOW OF AGENDA-SETTING?

The present study integrates two concepts: the notion of opinionleadership, as conceptualized and measured by the Strength ofPersonality (SP) scale, and the agenda-setting process. Thus,we suggest and test a two-step flow model in which certain individuals,the influentials, identify emerging issues in the mass mediaand then diffuse these issues to others via their personal networks.Based on a series of six national surveys conducted in Germany(1990) measuring issue salience and various personal characteristics,this study highlights the role certain individuals play in theemergence of the public agenda. The degree to which individualscan be influenced, measured by the SP scale, is found to bea powerful predictor of the formation of personal agendas, withhigh SP individuals differing from others in their identificationof emerging public issues. However, the analysis reveals thecomplexity of these relationships: they depend on the obtrusivenessof the issue, and they vary over time and location (East orWest Germany). The findings encourage the empirical pursuitof the suggested ‘two-step flow model’ as appliedto the agenda-setting process.     

Resource interdependence,student interactions and performance in cooperative learning

Two studies were carried out during university workshops, and analyzed the effects of resource interdependence on student‐student interactions, and the impact of these interactions on performance. Students worked cooperatively, either on complementary information (positive resource interdependence) or on identical information (resource independence). In Study 1, analysis of videotaped interactions revealed that working on complementary information produced more positive interactions; however this was not sufficient to prevent students who had no direct access to the information from being disadvantaged, because of informational dependence. In Study 2, with simpler texts allowing better information transmission, performance was favored when students worked on complementary information. Moreover, working on identical information not only enhanced confrontations of point of views, it also elicited competence threat. Further analysis revealed that competence threat mediated resource interdependence effect on performance. Discussion provides insights into the conditions in which different cooperative methods can benefit learning.     

Fulfilling the Promise of Professional Development

It is ironical that developments in the field of education call for teachers to differentiate instruction as a pre-requisite for effective learning,while teacher education and continuing professional development adhere to a one-size-fits-all philos- ophy. In general,professional development initiatives are part of'reform packages'with decisions about what,when,and