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HelpTest Code PTINR Prothrombin Time (PT) with INR, Plasma
Methodology
Photometric, Sensitive Synthetic Reagents (Recombiplastin
2G))
Useful for evaluation of extrinsic coagulation system; as a screen
for congenital deficiencies of Factors II, V, VII, and X; for
quantitating deficiencies of prothrombin; evaluation of
dysfibrinogenemia, afibrinogenemia (complete), coumarin or warfarin
effect, liver failure, disseminated intravascular coagulation; and
as a screen for vitamin K deficiency.
Performing Laboratory
St. Clair Hospital Laboratory
Specimen Requirements
1 light blue-top (3.2% sodium citrate) tube (0.3 mL of sodium citrate plasma). Centrifuge blood as soon as possible, or send unspun blood to laboratory within 4 hours of draw.
Note: If multiple tubes are being drawn, see “Order of Draw Instructions” in “Specimen Collection, Preparation, and Transport” in “General Information.”
Reference Values
PROTHROMBIN TIME
9.6-12.8 seconds
INR
Therapeutic range: 0.9-1.1
Critical value (automatic call-back): >5.0
Day(s) Test Set Up
Monday through Sunday