Skip Ribbon Commands
Skip to main content
Navigate Up
Search
Test Code
Search
Laboratory Section
Test Category
Browse By Test Name
# 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 - 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​
Frozen (-70°C)​ 6 Months​
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​
Frozen (-70°C)​ 6 Months​
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.