Impedance Aggregometry

ROTEM® platelet

Impedance Aggregometry

The impedance aggregometry is a diagnostic procedure which measures the platelet function in whole blood. With the influence of von Willebrand factor (vWF) at the place of the injury, the platelet stick to the exposed collagen (= adhesion). This leads to activation of further platelets. Fibrinogen plays a key role in platelet aggregation.

The ROTEM® platelet module runs in conjuction with the ROTEM® delta system. Measurements can be performed on both systems simultaneously.


Kolde, Haemostasis, 2nd edition 2004

Detection method

A whole blood sample is placed into a cuvette with two electrodes. The result is represented via three parameters A6 (Amplitude at 6 minutes), AUC (area under the curve) and MS (maximum slope).

150µl Diluent + 150µl whole blood

20µl Diluent for reconstition of the lyophilized reagent

12µl reagent for the assay

  • The impedance between both electrodes will be measured.
  • After adding the reagent, the platelets will be activated.
  • Within the next minutes the platelets will aggregate to the electrodes.
  • The measured impedance between the electrodes will increase and will be graphically displayed as a curve.

With the ROTEM® platelet differential diagnosis and the tests ADPTEM, TRAPTEM and ARATEM the reason for a decreased platelet aggregation can be determined. Rapid test results can help clinicians identify between surgical bleeding and platelet dysfunction, and make the monitoring of platelet therapy possible.

platelet measuring principle_EN
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