BACKGROUND In patients receiving heparin infusions, variations in specimen collection technique may contribute to inaccurate measurements of activated partial thromboplastin time (aPTT). OBJECTIVES To determine if there is a difference in aPTT results between specimens collected from a central venous access device (CVAD) compared with venipuncture in patients receiving heparin infusions. ME...

We have previously reported that plasma fibrin D-dimer (a marker of turnover of cross-linked fibrin) showed a strong and independent association with incident ischaemic heart disease (IHD) in the Caerphilly Study cohort of 1,998 men aged 49-65. To establish the specificity of this finding, we assayed plasma samples from this cohort with a more specific assay for fibrin D-dimer: this showed an a...

BACKGROUND The commonly recommended therapeutic range for patients receiving unfractionated heparin of 1.5 to 2.5 times the control activated partial thromboplastin time (aPTT) is not universally applicable. It has been suggested that the therapeutic range for each aPTT reagent should be based on plasma heparin levels. We sought to identify an aPTT ratio that corresponds to therapeutic anti--fa...

Weight-adjusted nomograms have been a significant advance in the use of unfractionated heparin (UFH). Clinical trials have demonstrated the ability of weight-adjusted nomograms to achieve a therapeutic activated partial thromboplastin time (aPTT) more rapidly than with standard UFH dosing. Despite this advantage, a significant number of patients have subtherapeutic and supratherapeutic aPTTs. R...

In this paper, a microcantilever-based system enabling multiple coagulation tests on the same disposable cartridge is demonstrated. The system consists of independent cartridge and reader unit. The actuation of the nickel cantilevers is conducted remotely with an external electro-coil and remote optical read-out is utilized for sensing. Both Prothrombin Time (PT) and activated Partial Thrombopl...

OBJECTIVES The purpose of this study was to determine the biological stability of heparin and to test for physical compatibility in heparin/antibiotic solutions in concentrations suitable for antibiotic lock therapy. METHODS Solutions were prepared with heparin 5000 U/mL or heparin 10 U/mL and cefazolin 10 mg/mL, ampicillin 10 mg/mL, or piperacillin 40 mg/mL. Solutions of vancomycin 2.5 mg/mL...

Thromb Haemost 2006; 96: 545–6 The current theme issue ofThrombosis and Haemostasis focuses on a panel of important topics regarding laboratory methods in the haemostatic laboratory. There is general agreement that tailoring laboratory assays to correlate with clinical phenotypes is essential for effective coagulation monitoring. Thus, it is not surprising that during the last decade concepts f...

We have studied factor VII activation by measuring the ratio of factor VII clotting to coupled amidolytic activity (VIIc/VIIam) and cleavage of 125I-factor VII. In purified systems, a low concentration of Xa or a higher concentration of IXa rapidly activated 125I-factor VII, yielding a VIIc/VIIam ratio of 25 and similar gel profiles of heavy and light chain peaks of VIIa. On further incubation,...

Transmittance waveform (TW) analysis has been proposed as a method of both prediction and monitoring of non-overt and overt disseminated intravascular coagulation. This study assessed the use of the rapidTW of the activated partial thromboplastin time in the detection of sepsis in 49 consecutive neutropenic haemato-oncology patients. A slope 1 cut-off value of -0.050 was found to be optimum giv...