| 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 # |
Partial Thromboplastin Time, Activated : 763
MessageThe plasma aliquot must remain frozen. Freeze thaw cycle will adversely affect specimen integrity. CRITICAL FROZEN: Separate specimens must be submitted when multiple tests are ordered.
Test Code
PTT or 763
Alias/See Also
APTT; Partial Thromboplastin Time, Activated; PTT
CPT Codes
85730
Transport Container
Whole blood: Collect specimen in light blue-top 3.2% sodium citrate tube. Tube should be filled at 100% +/- 10%. Correct ratio of blood to citrate is critical. Mix by inversion 4 times. Maintain specimen at room temperature. Do not uncap. Observe room temperature stability parameters.
Platelet-poor plasma: Centrifuge light blue-top tube for 15 minutes at approximately 1500g within 60 minutes of collection. Using a plastic pipette, remove plasma, taking care to avoid the WBC/platelet buffy layer, and place into a plastic vial. Centrifuge a second time and transfer platelet-poor plasma into a new plastic vial. Plasma must be free of platelets (<10,000/mcL). Freeze immediately and ship on dry ice.
NOTE: Patients who have hematocrit values above 55 percent should have the anticoagulant adjusted to maintain the 9:1 ratio. Use the following formula to determine the amount of anticoagulant to use: [(100 – Hct) / (595 – Hct) ]* total volume = amount of anticoagulant required.
Platelet-poor plasma: Centrifuge light blue-top tube for 15 minutes at approximately 1500g within 60 minutes of collection. Using a plastic pipette, remove plasma, taking care to avoid the WBC/platelet buffy layer, and place into a plastic vial. Centrifuge a second time and transfer platelet-poor plasma into a new plastic vial. Plasma must be free of platelets (<10,000/mcL). Freeze immediately and ship on dry ice.
NOTE: Patients who have hematocrit values above 55 percent should have the anticoagulant adjusted to maintain the 9:1 ratio. Use the following formula to determine the amount of anticoagulant to use: [(100 – Hct) / (595 – Hct) ]* total volume = amount of anticoagulant required.
Transport Temperature
Whole blood: Room temperature.
Separated platelet-poor plasma: Frozen.
Separated platelet-poor plasma: Frozen.
Specimen Stability
Unopened light blue-top tube: Room temperature: 24 hours
Separated platelet-poor plasma: Room temperature: Unacceptable; Refrigerated: Unacceptable; Frozen: 14 days
Separated platelet-poor plasma: Room temperature: Unacceptable; Refrigerated: Unacceptable; Frozen: 14 days
Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Tubes not filled within 90% of the fill line will be rejected by the lab.
Methodology
Clotting
Setup Schedule
Sunday - Saturday
Report Available
1 day
Limitations
This test has not been validated for monitoring unfractionated heparin therapy. For testing that is validated for this type of therapy, please refer to Heparin, Anti-Xa, Unfractionated Assay (test code XAUNF or 1001022).
Reference Range
PTT
≤6 months Not established
>6 months 23-32 sec
Flagging not provided. Pediatric reference intervals have not been established. Based on published literature, the adult reference interval (23-32 seconds) is generally applicable down to approximately 6 months of age with younger patients having a slightly higher upper limit by several seconds.
≤6 months Not established
>6 months 23-32 sec
Flagging not provided. Pediatric reference intervals have not been established. Based on published literature, the adult reference interval (23-32 seconds) is generally applicable down to approximately 6 months of age with younger patients having a slightly higher upper limit by several seconds.
Clinical Significance
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.
Performing Laboratory
med fusion
