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Thrombosis Topics, Prediction Indicators

https://www.mayocliniclabs.com/test-catalog/Clinical+and+Interpretive/602172

https://www.webmd.com/a-to-z-guides/partial-thromboplastin-time-test#1

webmd.com/a-to-z-guides/partial-thromboplastin-time-test#1(opens in a new tab)

Partial Thromboplastin Time, Activated 

Updated: Jul 30, 2019 

  • Author: Muhammad Bader Hammami, MD; Chief Editor: Eric B Staros, MD

Reference Range

Partial thromboplastin time (PTT) and activated partial thromboplastin time (aPTT) are used to test for the same functions; however, in aPTT, an activator is added that speeds up the clotting time and results in a narrower reference range. The aPTT is considered a more sensitive version of the PTT and is used to monitor the patient’s response to heparin therapy.

The reference range of the aPTT is 30-40 seconds. [123]

The reference range of the PTT is 60-70 seconds.

In patients receiving anticoagulant therapy, the reference range is 1.5-2.5 times the control value in seconds.

Critical values that should prompt a clinical alert are as follows:

  • aPTT: More than 70 seconds (signifies spontaneous bleeding)

  • PTT: More than 100 seconds (signifies spontaneous bleeding)

https://www.mayocliniclabs.com/test-catalog/Clinical+and+Interpretive/602172

https://www.webmd.com/a-to-z-guides/partial-thromboplastin-time-test#1

webmd.com/a-to-z-guides/partial-thromboplastin-time-test#1(opens in a new tab)

Partial Thromboplastin Time, Activated 

Updated: Jul 30, 2019 

  • Author: Muhammad Bader Hammami, MD; Chief Editor: Eric B Staros, MD

Reference Range

Partial thromboplastin time (PTT) and activated partial thromboplastin time (aPTT) are used to test for the same functions; however, in aPTT, an activator is added that speeds up the clotting time and results in a narrower reference range. The aPTT is considered a more sensitive version of the PTT and is used to monitor the patient’s response to heparin therapy.

The reference range of the aPTT is 30-40 seconds. [123]

The reference range of the PTT is 60-70 seconds.

In patients receiving anticoagulant therapy, the reference range is 1.5-2.5 times the control value in seconds.

Critical values that should prompt a clinical alert are as follows:

  • aPTT: More than 70 seconds (signifies spontaneous bleeding)

  • PTT: More than 100 seconds (signifies spontaneous bleeding)

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