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. 2022 Feb;44(1):209-215.
doi: 10.1111/ijlh.13727. Epub 2021 Oct 5.

A single-institution retrospective study of causes of prolonged prothrombin time and activated partial thromboplastin time in the outpatient setting

Antonious Z Hazim  1 , Gordon J Ruan  2 , Ryan B Khodadadi  3 , Joshua P Slusser  4 , Ariela L Marshall  2   5 , Rajiv K Pruthi  2   5
Affiliations

A single-institution retrospective study of causes of prolonged prothrombin time and activated partial thromboplastin time in the outpatient setting

Antonious Z Hazim et al. Int J Lab Hematol. 2022 Feb.

Abstract

Introduction: An algorithmic approach, termed the prolonged clot time profile (PROCT), consisting of initial screening with prothrombin time (PT) and activated partial thromboplastin time (aPTT), reflexive mixing studies if indicated, and follow-up assays depending on initial testing results, offers an efficient approach to delineate the etiology of a prolonged PT/aPTT. Herein, we present the outcomes of the PROCT in the outpatient setting.

Methods: In this retrospective study, we reviewed medical records of consecutive outpatients who had prolonged PT and/or aPTT noted in the routine coagulation laboratory and who had PROCT ordered in our institutional Special Coagulation Laboratory between 2010 and 2017.

Results: One hundred and six patients, median age 55 years (IQR 30-67), met our study criteria. Twenty-nine patients had normal PT/aPTT, while 77 had persistent abnormalities and underwent reflexive testing. A prolonged PT, aPTT, or PT and aPTT was noted in 27 (35%), 27 (35%), and 23 (30%) respectively. Forty-nine (64%) had an acquired condition, 17 (22%) had a congenital condition, 7 (9%) had unclear etiology, and 4 (5%) were the result of laboratory artifact. The most common known cause of an isolated prolonged PT in our study was vitamin K deficiency in 8 (10%), the most common cause of an isolated prolonged aPTT was lupus anticoagulant in 4 (5%), and the most common cause of prolonged PT and aPTT was liver disease in 11 (14%).

Conclusion: Prolonged PT/aPTT have a wide range of causes, including artifactual prolongation or abnormalities in secondary hemostasis due to both inherited and acquired conditions.

Keywords: Congenital factor deficiency; acquired factor deficiency; anticoagulation; liver disease; vitamin K deficiency.

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References

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