BACKGROUND In an effort to improve interlaboratory agreement in the monitoring of unfractionated heparin (UFH), the College of American Pathologists (CAP) recommends that the therapeutic range of the activated partial thromboplastin time (APTT) be defined in each laboratory through correlation with a direct measure of heparin activity such as the factor Xa inhibition assay. Whether and to what ...

Using the chromogenic substrate S-2222, we have optimized and automated an amidolytic assay for heparin. The assay is based on the detection of anti-Xa activity generated by heparin in plasma. The method is reproducible (intra- and interassay CVs of 2.4 and 3.3%, respectively) and reliable in antithrombin III-deficient plasma. Results of this assay, obtained for plasma samples from patients and...

Unfractionated heparin (UFH) is widely used in the treatment and prophylaxis of thrombosis. The anticoa‐ gulant effect of UFH is monitored according to activated partial thromboplastin time (APTT). However, there are reports of cases in which hemorrhagic complications develop despite APTT being maintained within the therapeutic range. This indicates there are problems with the monitoring method...

Here we report the first application of a fractal analysis of the viscoelastic properties of incipient blood clots. We sought to ascertain whether the incipient clot's fractal dimension, D(f,) could be used as a functional biomarker of hemostasis. The incipient clot is formed at the gel point (GP) of coagulating blood, the GP demarcating a functional change from viscoelastic liquid to a viscoel...

Essentials Activated partial thromboplastin time (APTT) or anti-Xa tests are used to monitor heparin. Prothrombinase-induced Clotting Time (PiCT) was compared to APTT in a clinical study. PiCT shows higher correlation to anti-Xa than APTT does and is more comparable between centers. PiCT demonstrates significantly higher accuracy and reliability than APTT in heparin monitoring. SUMMARY Backgr...

Three sulphated polysaccharides labelled at the reducing end with three different chemical treatments [2-aminopyridine (2-AP), 8-amino-1,3,6-trisulphonic acid (ANTS) and 6-(biotinyl)-aminocaproylhydrazide (BACH)] were compared. Molecular weight, chemical composition, nuclear magnetic resonance features and anticoagulant activity expressed as activated partial thromboplastin time were studied to...

In order to determine their value for estimating the heparin concentration in plasma, we established the relationship between test result and heparin concentration in plasma from various individuals, for five assays used with heparin treatment. Only assays which can be carried out routinely in clinical laboratories were considered. The thrombin time and the whole blood recalcification time give...

Laboratory monitoring is widely recommended to measure the anticoagulant effect of unfractionated heparin and to adjust the dose to maintain levels in the target therapeutic range. The most widely used laboratory assay for monitoring unfractionated heparin therapy is the activated partial thromboplastin time (aPTT). A fixed therapeutic range for the aPTT of 1.5 to 2.5 times the control value ha...