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Partial thromboplastin time (PTT)

Screening test of the intrinsic plasmatic coagulation cascade, in particular factor I, II, V, VIII-XII. In addition, therapy with unfractionated heparin can be monitored with PTT. The effect of low molecular weight heparins is not detected by PTT.

Standard value:

Depending on reagent and laboratory 20–40 s.

Laboratory test method:

Ball coagulometer.

Indications:

Screening test for coagulation disorders, treatment with heparin.

Differential Diagnosis of Prolonged PTT

Congenital coagulation factor deficiency (factor I, II, V, hemophilia A, hemophilia B, X, XI), von Willebrand disease (vWD).
Acquired factor deficiencies due to severe hepatic dysfunction, inhibitors of coagulation factors (circulating anticoagulants), antiphospholipid antibodies.
Therapy with heparin or direct oral anticoagulants (DOAK), overdose of warfarin or phenprocoumon.

Differential Diagnosis of shortened PT

Activation of the coagulation system due to traumatic venipuncture or acute-phase-response.

CRP in serum

Index

Prothrombin time

Index: 1–9 A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

References

Guder, W. G. & Nolte, J. Das Laborbuch für Klinik und Praxis
Urban + Fischer, 2009

Siegenthaler 1988 SIEGENTHALER, W. ; SIEGENTHALER, W. (Hrsg.): Differentialdiagnose innerer Krankheiten.
Georg Thieme Verlag, Stuttgart, New York., 1988

Deutsche Version: Gerinnungstest PTT

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