Test Name: Prothrombin Time (PT)
Specimen Type: Sodium Citrated Plasma
Specimen required: 2-3 Cc Light-blue top (1.8% or 3.2% sodium citrate) vial
Day Performed: Daily
Reporting Time: 8 Hours STAT Reporting Time: 70 MINUTES
Methodology: Diagon CoagM
CLINICAL SIGNIFICANCE:
In the absence of blood thinning medicines, a high PT result and an INR above 1.1 may be due to Bleeding disorders, Disseminated Intravascular Coagulation (DIC, Liver disease or Low level of vitamin K
- INR from 2.0 to 3.0 indicates bleeding problems.
- INR higher than 3.0 indicates higher risk for bleeding.
- INR results lower than 2.0 indicates risk for developing a blood clot.
A PT result that is too high or too low in the presence of blood thinning medicines may be due to the wrong dose of medicine, alcohol intake, taking certain over-the-counter (OTC) medicines, vitamins, supplements, cold medicines, or antibiotics.
References:
- Lee GM, Ortel TL. Antithrombotic therapy. In: McPherson RA, Pincus MR, eds. Henry’s Clinical Diagnosis and Management by Laboratory Methods. 24th ed. Philadelphia, PA: Elsevier; 2022: chap 43.
- Schafer AI. Approach to the patient with bleeding and thrombosis. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 26th ed. Philadelphia, PA: Elsevier; 2020: chap 162.