scope:

This Standard is applicable to the determination of the activated partial thromboplastin time (APTT) in plasma obtained from citrated venous blood.

The activated partial thromboplastin time is used:

a) as a global test for the endogenous coagulation cascade (factors VIII, IX, XI, XII, prekallikrein, HMWkininogen); as well as for fibrinogen and the factors II, V und X;

b) for monitoring the influence of pharmacotherapy, e.g. that of unfractionated heparin or argatroban therapy, on blood coagulation;

c) as a proof of acquired inhibitors of the factors of the endogenous coagulation system, especially factor VIII inhibitors as a result of haemophilia treatment and so-called lupus anticoagulants.

The APTT may not be used for the surveillance of the pharmacotherapeutic influence of blood coagulation by some direct thrombin inhibitors or factor Xa-inhibitors (e.g., dabigatran, rivaroxaban, apixaban, edoxaban).

When determining the activated partial thromboplastin time by the procedure described in this standard, the results are only comparable if qualitatively similar partial thromboplastins and activating agents are used.

NOTE "Qualitatively similar" means similar sensitivity to coagulation and anticoagulant factors.