Routine Coagulation.

The term 'routine coagulation' typically applies to hemostasis tests routinely performed in hematology laboratories, often available 24/7, and potentially ordered urgently. These tests would comprise of the prothrombin time (PT), the PT converted to an international normalized ratio, the activated partial thromboplastin time (often called partial thromboplastin time in North American laboratories) and potentially the thrombin time, the D-dimer assay, and fibrinogen assays. Although other tests could feasibly be offered (testing feasible), there are good reasons for not including all of these other tests in all routine coagulation laboratories.

Favaloro EJ ，Pasalic L 《-》

Pitfalls in the assessment of disseminated intravascular coagulation in patients on dabigatran.

Dabigatran is an orally administrated anticoagulant that directly inhibits thrombin. However, the drug can affect routine coagulation tests such as prothrombin time (PT), activated partial thromboplastin time (APTT) and thrombin time (TT), as well as haemostasis assays, (e.g., clot-based coagulation factor assays). There are limited data on the effect of dabigatran on some fibrinogen measurements and on D-dimer assays, both important components in the laboratory assessment of disseminated intravascular coagulation (DIC). The objectives of this study were: (1) to determine the effects of various concentrations of dabigatran on fibrinogen and D-Dimer assays; and (2) to compare the von Clauss method of fibrinogen measurement using two reagents with differing thrombin concentrations (35 UNIH/mL and 100 UNIH/mL) and PT-derived fibrinogen measurement in the presence of the drug. Aliquots of pooled normal plasma were spiked with different concentrations of dabigatran to reflect in vivo on-therapy levels as well as levels observed in cases of massive accumulation of the drug. Of the routine coagulation assays, in ascending order of sensitivity to dabigatran were PT, APTT and TT. The von Clauss method of measuring fibrinogen using a reagent with low thrombin concentration was affected even at drug levels corresponding to in vivo trough concentrations, whereas the reagent with higher thrombin concentration was only affected at drug levels that were above observed peak concentrations in patients taking 150 mg of the drug twice daily. PT-derived fibrinogen was affected at approximately in vivo peak drug concentrations. The D-dimer assay was affected only at drug concentrations well above peak drug levels. Attempts at in vitro neutralisation of the drug with DOAC-Stop resulted in 'correction' of some of these measurements depending on drug concentration. Like the routine coagulation assays, there is a dabigatran concentration dependent effect on the accuracy of fibrinogen and D-dimer assays. Falsely low fibrinogen results due to dabigatran may confound the assessment of DIC and diagnostic laboratories need to evaluate the performance of their own reagents.

Kanda GS ，Ho WK ，Rodrigues C ，Bousounis A ，Hogan C ... -  《-》

[Diagnostic of blood coagulation].

Barthels M 《Hamostaseologie》

Croatian Society of Medical Biochemistry and Laboratory Medicine: National recommendations for blood collection, processing, performance and reporting of results for coagulation screening assays prothrombin time, activated partial thromboplastin time, thr

Bronić A ，Coen Herak D ，Margetić S ，Milić M ... -  《-》

Is it acceptable to use coagulation plasma samples stored at room temperature and 4°C for 24 hours for additional prothrombin time, activated partial thromboplastin time, fibrinogen, antithrombin, and D-dimer testing?

Coagulation laboratories are faced on daily basis with requests for additional testing in already analyzed fresh plasma samples. This prompted us to examine whether plasma samples stored at room temperature (RT), and 4°C for 24 hours can be accepted for additional prothrombin time (PT), activated partial thromboplastin time (aPTT), fibrinogen (Fbg), antithrombin (AT), and D-dimer testing. We measured PT, aPTT, Fbg in 50 and AT in 30 plasma samples with normal and pathological values, within 4 hours of blood collection (baseline results) and after 24-hours storage at RT (primary tubes), and 4°C (aliquots). D-dimer stability was investigated in 20 samples stored in primary tubes at 4°C. No statistically significant difference between baseline results and results in samples stored at RT and 4°C was observed for PT (P=.938), aPTT (P=.186), Fbg (P=.962), AT (P=.713), and D-dimers (P=.169). The highest median percentage changes were found for aPTT, being more pronounced for samples stored at 4°C (13.0%) than at RT (8.7%). Plasma samples stored both at RT and 4°C for 24 hours are acceptable for additional PT, Fbg, and AT testing. Plasma samples stored 24 hours in primary tubes at 4°C are suitable for D-dimer testing.

Rimac V ，Coen Herak D 《-》