Liquid compontent kits containing phospholipid extract and silica contact activator. Sensitive to heparin as well as factors and insensitive to lupus anticoagulant.

MediRox APTT liquid reagent is used for in vitro determination of the Activated Partial Thromboplastin Time (APTT). APTT is measured to obtain a global evaluation of the intrinsic pathway and for monitoring heparin anticoagulant therapy. The MediRox APTT reagent has been designed to provide an extra long reaction time in order to obtain a high resolution for clearest interpretation of results.

Liquid components, ready to use

Colloidal silicate contact activator

Insensitive to Lupus Anticoagulant

Highly sensitive to Heparin

Excellent factor sensitivity 


General Description

Activated partial thromboplastin time (APTT) is a commonly used screening test for haemostatic defects in the intrinsic and common pathway of the coagulation cascade, as well as the contact activation system. Thus, FV, FVIII, FIX, FX, FXI, FXII, prekallikrein and high‐molecular weight kininogen deficiencies can result in a prolonged APTT. Moreover, APTT is also suitable to monitor heparin treatment and, depending on the design of the reagent, for detection of lupus anticoagulant (LA). Since there is no international standard for APTT to correlate against, each APTT on the market has its own composition of phospholipids and activator, giving reagents different characteristics.

MRX APTT can be characterised as heparin, FVIII, FIX, FXI sensitive, while still being insensitive to presence of LA, since LA can cause a falsely pro-longed APTT. Thus it is suitable to monitor heparin treatment and for haemophilia screening, while less suitable to detect LA.

Performance Characteristics

MRX APTT reagent utilises a near colloidal contact activator to stimulate generation of FXIa by providing a surface for the interaction of high molecular weight kininogen, kallikrein and FXIIa. The contact activation is allowed to proceed at 37 °C for a period of time before calcium chloride is added to trigger further reactions and finally a formation of fibrin clot. 

MRX APTT reagent contains phospholipids and silicate to ensure a highly consistent and stable product. The product is designed to be insensitive to LA and to have high sensitivity to heparin.

Sensitivity & Specificity

Details & Typical Data

Product form: Liquid components
Normal Range: <35 sec
Abnormal Range: >35 sec

Heparin Sensitivity

Heparin APTT clotting time
0 IU/mL 30 sec
0,2 IU/mL 70 sec
0,4 IU/mL 174 sec

Factor Sensitivity

<1% 86 sec 71 sec 92 sec
10% 46 sec 44 sec 51 sec
40% 34 sec 34 sec 34 sec
100% 29 sec 29 sec 29 sec

Stability & Storage

Storage: 2-8 °C
Shelf life: 24 months at 2-8 °C
Open vial stability: 30 days at 2-8 °C

Ordering Information

Reference Number Product Description Pack Size
MRX930 Small APTT Kit 5x5 mL APTT + 5x5 mL CaCl₂
MRX931 Large APTT Kit 5x10 mL APTT + 5x10 mL CaCl₂
MRX171/172/173 Eximius Control Basic L1/L2/L3 10x1 mL pack per level
MRX181/182/183 Eximius Control PLUS L1/L2/L3 10x1 mL pack per level
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