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)

Abstract

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.

The stability of ‘add‐on’ coagulation assays in refrigerated citrated plasma stored on a packed cellular fraction

“…An estimated 27% of D‐Dimer requests in UHL are tested subsequently requested by a clinician following referral of the initial coagulation screen. In a recent survey, over half of laboratory centres (56%) used plasma from centrifuged primary coagulation containers for add‐on tests 10 . Previous studies have examined the effect of refrigeration on coagulation plasma aliquots 2,11 .…”

“…In a recent survey, over half of laboratory centres (56%) used plasma from centrifuged primary coagulation containers for add-on tests. 10 Previous studies have examined the effect of refrigeration on coagulation plasma aliquots. 2,11 However, the practice of aliquoting plasma from centrifuged primary coagulation containers for potential subsequent add-ons can be difficult to implement in some laboratories due to time, financial and space constraints.…”

Errors within the total laboratory testing process, from test selection to medical decision-making – A review of causes, consequences, surveillance and solutions

“…To ensure the right sample transportation, local requirements have to be defined and distributed to all clinicians, nursing staff and carriers (22,59). A survey among European laboratories on preanalytical practices for coagulation tests recently found that only 42% of participating laboratories are actually monitoring temperature during transportation (60). Reported proportions of unsuitable samples due to inappropriate time and temperature condi-tions can be as high as 3.4% and 1.2% of all samples received (Figure 5), respectively, and 1.9% in relation to the errors analysed (Figure 4) (7,44).…”

“…Since recommendations on centrifugation conditions from manufacturers of blood collection systems as well as other sources differ in time and speed, ranging from ≤ 1300xg to 4000xg, and from 3 to 15 minutes ), this preanalytical step may display large heterogeneity (58,(73)(74)(75). A survey carried out by the External Quality Assurance Providers in Laboratory Medicine (EQALM) recently confirmed that this practice is considerably variable across many European laboratories (60). Since blood tubes manufacturers cannot validate all available parameters on all analytical platforms, recommendations are mostly set to a longer centrifugation time at a lower speed to assure sample quality.…”

To disinfect or not to disinfect that is the question – Procedure when drawing blood for alcohol measurements in Denmark

“…In Denmark, individual laboratories may choose which combination of official guidelines and local protocols suit their local practices and quality assurance strategies. This autonomy may not be just a Danish phenomenon, as a study showed that only 63 % of European laboratories followed a national guideline regarding the handling and storage of blood samples for coagulation tests [ 3 ]. This autonomy may be a concern if locally developed protocols neither follow official guidelines nor the scientific evidence-based literature - as we previously observed for blood tube order of draw in Denmark [ 4 ].…”