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 #

PT and APTT

Test Code
PTAPT


Alias/See Also
Epic: LAB2400


Includes
Activated Partial Thromboplastin Time (aPTT)
Prothrombin Time


Preferred Specimen

Specimen Type: Whole blood

Collection Container: Light-blue top (3.2% sodium citrate)

Specimen Volume: 3 mL




Other Acceptable Specimens
Specimen Type: Platelet-poor plasma

Collection Container: Light-blue top (3.2% sodium citrate)


Instructions
Whole blood
  1. Collect sample, ensuring tube is completely filled to obtain a 9:1 (blood to anticoagulant) ratio.
  2. Submit sealed, unopened sample to laboratory.

Plasma
  1. Draw blood into a light blue (sodium citrate) tube.  Be sure to fill tubes completely.
  2. Mix gently 5 to 6 times (do not over mix).
  3. Centrifuge the sample for 10 minutes.
  4. Using a pipette, aliquot plasma into a plastic vial being careful not disturb the buffy coat.
  5. Centrifuge the plasma sample a second time for 10 minutes
  6. Using a pipette, aliquot the top portion of plasma into a plastic vial.  Be careful not to disturb the sediment at the bottom (leave approx. 0.25 mL of plasma at the bottom).
  7. Label each tube as "Plasma."
  8. Immediately freeze samples
For complete instructions, see Platelet Poor Plasma Instructions.


Specimen Stability

Platelet-poor plasma
Room temperature

   Outpatient: 12 hours
   Inpatient: 4 hours

Refrigerated: Unacceptable

Frozen (-20ºC): 2 weeks

Frozen (-70ºC): 6 months



Whole Blood

Room temperature
   Outpatient: 12 hours
   Inpatient (not on heparin): 4 hours
   Inpatient (on heparin): 1 hour

Refrigerated: Unacceptable

Frozen: Unacceptable




Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)

Samples that are short (QNS), over draws, clotted,     
  hemolyzed, or beyond stablility requirements may yield incorrect results.
 




Methodology

Coagulometric (Turbidimetric)



Setup Schedule

Daily




Report Available

Same day / 1 day




Reference Range
Prothrombin Time: 12.6 - 15.0 seconds
International Normalized Ratio (INR): 0.9 - 1.1
Activated Partial Thromboplastin Time (aPTT): 23 - 37 seconds


Clinical Significance

Inova Laboratories



2832 Juniper Street



Fairfax, VA 22031




Performing Laboratory
Inova Central Laboratory 2832 Juniper Street Fairfax, VA 22031


Last Updated: June 30, 2023
Last Review: N. Wolford, June 30, 2023


The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.