Activated Partial Thromboplastin Time (aPTT)
| Order Code: | PTT |
| Order Form: | Laboratory Requisition |
Specimen:
Plasma
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.
Testing
Schedule:
24 hrs/day, 7 days a week, including holidays.
Turn Around
Time:
2 hours (upon receipt in laboratory)
Reference Range:
23-31 seconds
Critical value: >50 seconds (on outpatients only)
Results called for inpatients only: >87 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 23-31 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.
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 23-31 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.
Methodology:
Optical clot detection.
Sample
Processing:
Centrifuge within two hours of draw time.
Aliquot serum/plasma into plastic container and cap (glass is not acceptable).
Centrifuge a second time at 3500 RPM for 10 minutes and aliquot into a new, labeled plastic tube.
Aliquot serum/plasma into plastic container and cap (glass is not acceptable).
Centrifuge a second time at 3500 RPM for 10 minutes and aliquot into a new, labeled plastic tube.
Sample
Storage:
Freeze specimen immediately.
Transport
Instructions:
Place specimen into zip-lock type 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
See Additional Information:
Hematology Critical Lab Values
Heparin Therapy
Phlebotomy Tubes and Order of Draw
Hematology Critical Lab Values
Heparin Therapy
Phlebotomy Tubes and Order of Draw