PB0103 - A retrospective study of causes of prolonged PT in outpatient setting from a single tertiary care centre in southern India

Background: Prothrombin time(PT)serves as crucial screening test for hemostasis,commonly ordered to assess bleeding,screen for coagulation factor deficiencies,monitor anticoagulant therapy.Despite its importance,there's scarcity of data regarding frequency of conditions leading to PT abnormalities.

Aims: Our aim was to examine our institutional experience with PT testing,explore reasons behind abnormal PT tests in outpatient practice and correlate these with clinical findings.

Methods: In this retrospective study,we analyzed records of patients who underwent PT testing at Hematology Laboratory,Amrita Hospital,Kochi from 2018 to 2022.Out patients with prolonged PT>17 secs by Mechanical clot detection method in TcoagDT100 were included in our study criteria.Patient demographics,indications for testing,use of anticoagulants,relevant medical diagnoses impacting coagulation,test results were retrieved.Data were presented using median/range and percentage.Missing data were not imputed,MS excel 2016 used for analysis.

Results: Over the study period,398647 patients performed PT testing,of which 4112 patients had prolonged PT,3439 were inpatients,thus excluded from study.Total of 673 patients met our study criteria.Among them,416(62 %) were male,with median age 56 years(range 1-94) and 257(38 %) were female,with median age 55 years (range 1-94).PT ranged from 18-92 secs in both males and females.We analysed established conditions known to influence coagulation,such as solid tumours,hematologic malignancies,liver and renal diseases, autoimmune/rheumatologic conditions and pregnancy that would potentially prolong PT.Table1 list summary of baseline patient characteristics.Subsequent clinical correlation unveiled that abnormal PT testing were due to underlying congenital conditions notably factor VII deficiency36(5.3%),7(1%)patients such as Factors X,Vdeficiency.Acquired causes of prolonged PT were liver disease195(29%),Haematological malignancy7(1%),RenalDisease13(2 %) and unknown etiology90(13.4 %)cases.

Conclusion(s): Despite being commonly ordered,little evidence exists on epidemiology and clinical correlation of PT testing.Our study underscores that abnormalities in hemostatic testing stem from various causes,including pre-test variables affecting results or marked abnormalities in secondary hemostasis due to inherited and acquired conditions.The study's strength lies in the algorithmic approach adopted for testing,though limitations exist due to its single-institution experience,potentially indicating referral bias.