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Partial Thromboplastin Time - APTT/PTT
Test Code: APTT
Synonyms/Keywords
PTT, APTT, Activated Partial Thromboplastin Time​
Specimen Requirements
Fasting Required Specimen Type Preferred Container/Tube Acceptable Container/Tube Specimen Volume Specimen Minimum Volume
(allows for 1 repeat)
Pediatric Minimum Volume
(no repeat)
No​ Whole Blood, Plasma​ Citrated Blue Top Tube (BTT)​ 1.0 mL Plasma​ 0.6 mL Plasma​
Collection Processing Instructions

Citrated Blue Top Tube (BTT) must be drawn to the fill line. Completely invert tube three or four times to mix. Do Not Shake. Centrifuge tube at 3000 rpm for 10 minutes or Stat Spin for 3 minutes at 8500 rpm with the brake OFF as soon as possible after collection.  Perform testing within 4 hours of sample collection or transfer plasma (avoiding platelet contamination) to polypropylene tube with plastic pipette for storage within two hours of collection.

If sending to another testing location: Send one frozen aliquot (1 mL) labeled with both APTT and Protime-INR labels if both APTT and Protime-INR ordered.​

Specimen Stability Information
Specimen Type Temperature Time
Whole Blood​ or Plasma Ambient or Refrigerated​ 4 Hours​
Plasma​ Frozen (-18°C)​ 2 Weeks​
Plasma​ Frozen (-70°C)​ 6 Months​
Plasma​ Frozen thawed​ 2 Hours​
Rejection Criteria
Specimens filled below the fill line
Clotted​
Frozen whole blood​
Known IV fluid or Hickman line fluid contamination​
Specimens with abnormal results that have  a Hct >55% that have not had the citrate anticoagulant adjusted​
Performing Laboratory Information
Performing Location Day(s) Test Performed Analytical Time Methodology/Instrumentation
Diagnostic Treatment Center​ Monday through Sunday​ Less than 2 hours​ Optical Clot Detection/Sysmex CA-1500​
Eau Claire​ ​Monday through Sunday​ ​Less than 2 hours​ ​Optical Clot Detection/Sysmex CA-1500​
Flambeau Hosp ​Monday through Sunday​ ​Less than 2 hours​ ​Optical Clot Detection/Sysmex CA-1500​
​Lakeview Medical Center ​Monday through Sunday​ ​Less than 2 hours​ ​Optical Clot Detection/Sysmex CA-1500​
Marshfield​ ​Monday through Sunday​ ​Less than 2 hours​ ​Optical Clot Detection/Sysmex CA-1500​
​Minocqua ​Monday through Sunday​ ​Less than 2 hours​ ​Optical Clot Detection/Sysmex CA-1500​
​Wausau ​Monday through Sunday​ ​Less than 2 hours​ ​Optical Clot Detection/Sysmex CA-1500​
Reference Range Information
Performing Location Reference Range
All Performing Sites 22.4 - 30.7 seconds​
​ See Critical Value List for list of current critical values​
Outreach CPTs
CPT Modifier
(if needed)
Quantity Description Comments
85730​
Synonyms/Keywords
PTT, APTT, Activated Partial Thromboplastin Time​
Ordering Applications
Ordering Application Description
​Centricity

​a. APTT

b. PTT (APPT)

​Cerner ​PTT
If the ordering application you are looking for is not listed, contact your local laboratory for assistance.
Specimen Requirements
Fasting Required Specimen Type Preferred Container/Tube Acceptable Container/Tube Specimen Volume Specimen Minimum Volume
(allows for 1 repeat)
Pediatric Minimum Volume
(no repeat)
No​ Whole Blood, Plasma​ Citrated Blue Top Tube (BTT)​ 1.0 mL Plasma​ 0.6 mL Plasma​
Collection Processing Instructions

Citrated Blue Top Tube (BTT) must be drawn to the fill line. Completely invert tube three or four times to mix. Do Not Shake. Centrifuge tube at 3000 rpm for 10 minutes or Stat Spin for 3 minutes at 8500 rpm with the brake OFF as soon as possible after collection.  Perform testing within 4 hours of sample collection or transfer plasma (avoiding platelet contamination) to polypropylene tube with plastic pipette for storage within two hours of collection.

If sending to another testing location: Send one frozen aliquot (1 mL) labeled with both APTT and Protime-INR labels if both APTT and Protime-INR ordered.​

Specimen Stability Information
Specimen Type Temperature Time
Whole Blood​ or Plasma Ambient or Refrigerated​ 4 Hours​
Plasma​ Frozen (-18°C)​ 2 Weeks​
Plasma​ Frozen (-70°C)​ 6 Months​
Plasma​ Frozen thawed​ 2 Hours​
Rejection Criteria
Specimens filled below the fill line
Clotted​
Frozen whole blood​
Known IV fluid or Hickman line fluid contamination​
Specimens with abnormal results that have  a Hct >55% that have not had the citrate anticoagulant adjusted​
Reference Range Information
Performing Location Reference Range
All Performing Sites 22.4 - 30.7 seconds​
​ See Critical Value List for list of current critical values​
For more information visit:
Performing Laboratory Information
Performing Location Day(s) Test Performed Analytical Time Methodology/Instrumentation
Diagnostic Treatment Center​ Monday through Sunday​ Less than 2 hours​ Optical Clot Detection/Sysmex CA-1500​
Eau Claire​ ​Monday through Sunday​ ​Less than 2 hours​ ​Optical Clot Detection/Sysmex CA-1500​
Flambeau Hosp ​Monday through Sunday​ ​Less than 2 hours​ ​Optical Clot Detection/Sysmex CA-1500​
​Lakeview Medical Center ​Monday through Sunday​ ​Less than 2 hours​ ​Optical Clot Detection/Sysmex CA-1500​
Marshfield​ ​Monday through Sunday​ ​Less than 2 hours​ ​Optical Clot Detection/Sysmex CA-1500​
​Minocqua ​Monday through Sunday​ ​Less than 2 hours​ ​Optical Clot Detection/Sysmex CA-1500​
​Wausau ​Monday through Sunday​ ​Less than 2 hours​ ​Optical Clot Detection/Sysmex CA-1500​
For billing questions, see Contacts
Outreach CPTs
CPT Modifier
(if needed)
Quantity Description Comments
85730​
For most current information refer to the Marshfield Laboratory online reference manual.