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- Ordering Info
To view specimen requirements and codes please select your laboratory:
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Prothrombin with INR and Partial Thromboplastin Times
One full unopened 3.2% sodium citrate (light blue-top) tube
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 plastic screw-cap vial and freeze at -20° C. Ship on dry ice.
Correct ratio of blood to citrate is critical. Do not overfill or underfill collection tube. Mix by inversion 4 times. For non-heparinized patients, maintain specimen at room temperature. Do not uncap. Stable 24 hours at room temperature.
3.2% sodium citrate (light blue-top) tube
Unopened light blue-top tube
Room temperature: 24 hours
Separated platelet-poor plasma
Room temperature: 2 hours
Refrigerated: 4 hours
Frozen -20° C: 14 days
Frozen -70° C: 6 months
Gross hemolysis • Gross lipemia • Improper blood to citrate ratio • Clotted • High hematocrit • Improper blood collection
Photo-optical Clot Detection
Set up: Daily; Report available: 1 day
PT/INR: 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.
aPTT: Expected impact by therapeutic levels (potential interference depends upon drug concentration): Warfarin: prolonged; Heparin (UFH or LMWH): prolonged; Dabigatran or Argatroban (Thrombin Inhibitors): prolonged; Rivaroxaban or Apixaban (Factor Xa Inhibitors): prolonged.
|Moderate - intensity Warfarin therapy||2.0-3.0|
|Higher - intensity Warfarin therapy||3.0-4.0|
PT/INR: 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.
aPTT: The aPTT is a screening test that will detect deficiencies or inhibitors to the intrinsic (Factors VIII, IX, XI and XII) and common (Factors II, V, X and Fibrinogen) pathway coagulation factors.
The Result and LOINC information listed below should not be used for electronic interface maintenance with Quest Diagnostics. Please contact the Quest Diagnostics Connectivity Help Desk for more information at 800-697-9302.NOTE: The codes listed in the table below are not orderable Test Codes.
|Result Name||LOINC Code||Component Name|
|INR||INR||6301-6||Coagulation tissue factor induced.INR|
|PT||PT||5902-2||Coagulation tissue factor induced|
|PTT||PTT||14979-9||Coagulation surface induced|
Reference ranges are provided as general guidance only. To interpret test results use the reference range in the laboratory report.
The CPT codes provided are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payer being billed.
LOINC assignment is based on a combination of test attributes, including the method used by the performing laboratory. For tests not performed by Quest Diagnostics, codes are assigned by the performing laboratory.
* The tests listed by specialist are a select group of tests offered. For a complete list of Quest Diagnostics tests, please refer to our Directory of Services.