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Prothrombin Time and International Normalized Ratio

Prothrombin Time and International Normalized Ratio is a topic covered in the Davis's Lab & Diagnostic Tests.

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Protime, PT, and INR.

Common Use:
To assess and monitor coagulation status related to therapeutic interventions and disorders such as vitamin K deficiency.

Plasma collected in a completely filled blue-top (sodium citrate) tube. If the patient’s hematocrit exceeds 55%, the volume of citrate in the collection tube must be adjusted.

Normal Findings:
(Method: Clot detection) 10 to 13 sec.

  • International normalized ratio (INR) = 0.9 to 1.1 for patients not receiving anticoagulation therapy; 2 to 3 for patients receiving treatment for venous thrombosis, pulmonary embolism, and valvular heart disease.
  • INR = 2.5 to 3.5 for patients with mechanical heart valves and/or receiving treatment for recurrent systemic embolism.
  • For patients receiving anticoagulants, therapeutic levels of warfarin are achieved by adjusting the dosage so the prothrombin time (PT) value is 1.5 to 2.5 times longer than normal or so the INR is between 2 and 3.

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Bladh, Mickey Lynn., and Anne M. Van Leeuwen. "Prothrombin Time and International Normalized Ratio." Davis's Lab & Diagnostic Tests, 7th ed., F.A. Davis Company, 2017. Nursing Central, nursing.unboundmedicine.com/nursingcentral/view/Davis-Lab-and-Diagnostic-Tests/425259/all/Prothrombin_Time_and_International_Normalized_Ratio.
Bladh ML, Van Leeuwen AM. Prothrombin Time and International Normalized Ratio. Davis's Lab & Diagnostic Tests. 7th ed. F.A. Davis Company; 2017. https://nursing.unboundmedicine.com/nursingcentral/view/Davis-Lab-and-Diagnostic-Tests/425259/all/Prothrombin_Time_and_International_Normalized_Ratio. Accessed April 23, 2019.
Bladh, M. L., & Van Leeuwen, A. M. (2017). Prothrombin Time and International Normalized Ratio. In Davis's Lab & Diagnostic Tests. Available from https://nursing.unboundmedicine.com/nursingcentral/view/Davis-Lab-and-Diagnostic-Tests/425259/all/Prothrombin_Time_and_International_Normalized_Ratio
Bladh ML, Van Leeuwen AM. Prothrombin Time and International Normalized Ratio [Internet]. In: Davis's Lab & Diagnostic Tests. F.A. Davis Company; 2017. [cited 2019 April 23]. Available from: https://nursing.unboundmedicine.com/nursingcentral/view/Davis-Lab-and-Diagnostic-Tests/425259/all/Prothrombin_Time_and_International_Normalized_Ratio.
* Article titles in AMA citation format should be in sentence-case
TY - ELEC T1 - Prothrombin Time and International Normalized Ratio ID - 425259 A1 - Bladh,Mickey Lynn, AU - Van Leeuwen,Anne M, BT - Davis's Laboratory & Diagnostic Tests UR - https://nursing.unboundmedicine.com/nursingcentral/view/Davis-Lab-and-Diagnostic-Tests/425259/all/Prothrombin_Time_and_International_Normalized_Ratio PB - F.A. Davis Company ET - 7 DB - Nursing Central DP - Unbound Medicine ER -