Activated Partial Thromboplastin Time (aPTT)
Label Mnemonic: | PTT |
Epic code: | LAB1117 |
Order form: | Laboratory Requisition |
Supply order: | Supply Order Form |
Billing: | Billing Policies |
CPT code: | 85730 |
Specimen(s):
Plasma More information
Collection Medium:
Light Blue top tube 1.8 mL (Na Citrate) |
Minimum:
Full draw; 1.8 mL light blue top (mix well) must be at least 90% full.
Rejection Criteria:
Short drawn tube, clot, traumatic tap (excessive hemolysis).
Testing
Schedule:
24 hrs/day, 7 days a week, including holidays.
Turn Around
Time:
1 hour (upon receipt in laboratory)
Reference Range:
22-31 seconds
Critical value: >50 seconds (on outpatients only)
Results called for inpatients only: >79 seconds
Critical value: >50 seconds (on outpatients only)
Results called for inpatients only: >79 seconds
Comments:
Blood from this test cannot be drawn through the IV line in which the
heparin is being administered to the patient. A separate venipuncture
is required at a different site.
Must be drawn swiftly with a clean venipuncture (no hematoma). Time drawn must be indicated on requisition. Obtain special tube from lab if patient's hematocrit is over 55%. If patient is on heparin therapy, samples must be in the lab within one hour after draw. All other samples must be tested within four hours.
Activated Partial Thromboplastin time (aPTT) may be performed on the same collection tube as Prothrombin Time and Fibrinogen.
Please print, complete and submit the Advance Beneficiary Notice (ABN) along with the Laboratory Requisition before shipping the specimen.
The current lot of aPTT reagent is consistent with previous lots. The mean of the reference range with this reagent is 27 seconds; the reference range is 22-31 seconds. The mean of the published therapeutic range for heparinization of 1.5-2.5 times the mean of the reference range (27) yields values of 40-67 seconds with this reagent. Based on our studies of heparin responsiveness, this is a reasonable target range to use with this reagent when treating uncomplicated venous thromboembolism.
Core Lab instrumentation changed from BCS-XP to CS-5100 on 12/16/2019.
Must be drawn swiftly with a clean venipuncture (no hematoma). Time drawn must be indicated on requisition. Obtain special tube from lab if patient's hematocrit is over 55%. If patient is on heparin therapy, samples must be in the lab within one hour after draw. All other samples must be tested within four hours.
Activated Partial Thromboplastin time (aPTT) may be performed on the same collection tube as Prothrombin Time and Fibrinogen.
Please print, complete and submit the Advance Beneficiary Notice (ABN) along with the Laboratory Requisition before shipping the specimen.
The current lot of aPTT reagent is consistent with previous lots. The mean of the reference range with this reagent is 27 seconds; the reference range is 22-31 seconds. The mean of the published therapeutic range for heparinization of 1.5-2.5 times the mean of the reference range (27) yields values of 40-67 seconds with this reagent. Based on our studies of heparin responsiveness, this is a reasonable target range to use with this reagent when treating uncomplicated venous thromboembolism.
Core Lab instrumentation changed from BCS-XP to CS-5100 on 12/16/2019.
Methodology:
Optical clot detection.
Sample
Processing:
Centrifuge within four hours of draw time.
Separate plasma into plastic container and cap (glass is not acceptable).
Centrifuge a second time to ensure platelet poor plasma and separate plasma into a new, labeled plastic tube, cap.
Separate plasma into plastic container and cap (glass is not acceptable).
Centrifuge a second time to ensure platelet poor plasma and separate plasma into a new, labeled plastic tube, cap.
Sample
Storage:
Freeze plasma immediately.
Transport
Instructions:
Place labeled specimen into zip-lock type biohazard bag; seal bag.
Place requisition into outside pocket of bag.
Place dry ice on top of specimen in Styrofoam container.
Place requisition into outside pocket of bag.
Place dry ice on top of specimen in Styrofoam container.
CPT Code:
85730
See also:
Prothrombin Time, Plasma
Prothrombin Time, Plasma