RT-7900 3-part Differential Hematology Analyzer

PRINCIPLE

The reagent is formed by a phospholipid obtained from a chloroform extract of rabbit brain, that performs as a platelet substitute and ellagic acid which is used as the activator of the coagulation mechanism. Once optimal activation is achieved by incubation of plasma with the reagent (at 37ºC/3min), the mixture was recalcifi ed and the coagulation time is determined.

DIAGNOSTIC USE

The determination of Activated Partial Thromboplastin Time (APTT) is mainly used to detect deficiencies in the fi rst stage of the coagulation mechanism, principally factors VIII, IX, XI, XII and Prekallikrein (Fletcher Factor). It is also sensitive to defi ciencies of the rest of factors except Factor VII. It is commonly used for monitoring heparin anticoagulant therapy. Levels approximately 40% of the normal value of Factors VIII, IX, XI and XII are sufficient to produce normal values of APTT. For levels lower than 40%, the APTT will be longer. Heparin, in the presence of adequate level of Antithrombin III, will also prolong the clotting time value. Single test result could not be used to make a clinical diagnosis. It should integrate clinical and laboratory data.