Haematex HRRS (Heparin Resistant Recalcifying Solution) is a blue-coded M/40 (0.02M) calcium solution containing a heparin-neutralizer for activated partial thromboplastin time (APTT), Kaolin clotting time (KCT), SACT or non-activated partial thromboplastin Time (NAPTT) tests.
Heparins are widely used in hospitals as anticoagulants. Unfractionated heparin is usually monitored using APTT and thrombin time tests. Often plasma samples are not identified as containing heparin and may be present as an unexpected contaminant. Thus the reason for prolonged APTT or KCT tests may not be apparent and laboratory testing may not be simple. Laboratories may find it useful to have a simple method for confirming the presence of heparin before going on to other investigations as may be required. The HRRS can be substituted for the usual M/40 calcium chloride solution in APTT and KCT tests to virtually eliminate the effect of unfractionated heparin concentrations up to 1u/ml in normal plasma.
Several methods are available to remove heparin including heparinase enzyme (expensive), adsorbing agents such as ECTEOLA cellulose (not so simple) and specially treated filters. Some polymers have also been widely used to neutralize heparin, however, in excess, they can interfere with contact activators used in most APTT reagents. Thus it is more reliable to add the heparin neutralizing agent in the calcium chloride solution after the contact activation stage in APTTs or KCTs. The HRRS is a simple and unique product which can play a regular role in routine coagulation testing.