International Normalized Ratio (INR)

Orderable EAP code:

LAB00689

Billable EAP Codes:

80001820 x 1

CPT Codes:

85610 x 1

Lab Section:

Core Lab

Turnaround Time:

Routine: 2 Hours
Urgent: 1 Hour

Test Schedule:

24 hours, 7 days a week.

Units:

INR

Critical Values:

Greater than or equal to 5.10

Specimen Requirements:

3.2% sodium citrate tubes are acceptable provided they are filed to the line on the manufacturers label. Tubes must be full (see comments below). Whole blood specimens are stable for 12 hours at room temperature. Citrate plasma separated from cells is stable for up to 14 days at -20 degrees C.

Pediatric Specimen Requirements:

Add blood to the 1.3 mL mark of Pediatric BLUE top tube, 3.2% sodium citrate.

Reference Range:

INR: 0.86 to 1.20 INR
PT: 9.6 – 13.5 seconds

PT INR therapeutic ranges for full anticoagulation
INR for venous thromboembolism: 2.0 to 3.0
INR for most patients with mech. valves: 2.5 to 3.5

Comments:

Draw volume is critical due to the liquid anticoagulant. Allow tubes to fill by vacuum.

  • Tubes with rubber stopper: fill to line on label.
  • Tubes with plastic (Hemogard) cap: the fill level is above the top of the label.
  • Syringe: do not remove the vacutainer stopper. Insert the needle through the stopper and allow the tube to fill by vacuum. Do not overfill the vacutainer.
  • Pediatric tubes have no vacuum. Remove the cap and add blood to the 1.3 mL mark. Do not overfill.

Synonyms:

Coags
INR
Prothrombin Time
Protime
PT