| A B C D E F G H I J K L M N O P Q R S T U V W X Y Z # |
PROTIME-INR
Test CodeLAB320
Quest Code
8847
CPT Codes
85610
Preferred Specimen
One full unopened 3.2% sodium citrate (light blue-top) tube
Minimum Volume
Ratio of blood to citrate is critical. Submit difficult draws in pediatric (light blue-top) tube
0.5 mL frozen plasma
0.5 mL frozen plasma
Other Acceptable Specimens
1 mL frozen plasma: If the specimen will be delayed longer than 48 hours, centrifuge specimen for 15 minutes at 2500-3500 rpm. Using a plastic pipette, remove plasma, taking care to avoid the WBC/platelet (buffy) layer and place into a transport tube and freeze at -20° C. Ship on dry ice.
Instructions
A completely filled tube is necessary because the correct ratio of blood to citrate is critical (9:1).
Mix by gentle inversion 3-4 times. Do not uncap.
Mix by gentle inversion 3-4 times. Do not uncap.
Transport Container
3.2% sodium citrate (light blue-top) tube
Transport Temperature
Room temperature
Specimen Stability
Unopened light blue-top tube
Room temperature: 48 hours
Refrigerated: Unacceptable
Frozen: Unacceptable
Separated platelet-poor plasma
Room temperature: Unacceptable
Refrigerated: Unacceptable
Frozen: 14 days
Room temperature: 48 hours
Refrigerated: Unacceptable
Frozen: Unacceptable
Separated platelet-poor plasma
Room temperature: Unacceptable
Refrigerated: Unacceptable
Frozen: 14 days
Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Gross hemolysis • Grossly lipemic • Improper blood to citrate ratio • High hematocrit • Improper blood collection
Methodology
Photo-Optical Clot Detection
Setup Schedule
Mon-Sat
Report Available
2 days
Limitations
Expected impact by therapeutic levels (potential interference depends upon drug concentration): Warfarin: prolonged; Heparin (UFH or LMWH): little to no effect (reagent contains a heparin neutralizer); Dabigatran or Argatroban (Thrombin Inhibitors): normal to prolonged; Rivaroxaban or Apixaban (Factor Xa Inhibitors): prolonged.
Reference Range
INR
PT
Flagging not provided. Pediatric reference intervals have not been established. Based on published literature, the adult reference interval (9.0-11.5 seconds) is generally applicable down to approximately 3 months of age with younger patients having a slightly higher upper limit by several seconds. Warfarin Therapeutic INR Range: 2.0 - 3.0
| ≤3 months | Not established |
| >3 months | |
| Reference range | 0.9-1.1 |
| Moderate-intensity Warfarin therapy | 2.0-3.0 |
| Higher-intensity Warfarin therapy | 3.0-4.0 |
PT
| ≤3 months | Not established |
| >3 months | 9.0-11.5 sec |
Flagging not provided. Pediatric reference intervals have not been established. Based on published literature, the adult reference interval (9.0-11.5 seconds) is generally applicable down to approximately 3 months of age with younger patients having a slightly higher upper limit by several seconds. Warfarin Therapeutic INR Range: 2.0 - 3.0
Clinical Significance
Screening test for abnormalities of coagulation factors that are involved in the extrinsic pathway. Also used to monitor effects of Warfarin therapy and to study patients with hereditary and acquired clotting disorders.
Performing Laboratory
| Quest Diagnostics-Lenexa |
| 10101 Renner Blvd |
| Lenexa , KS 66219-9752 |
Last Updated: August 13, 2021
